rename libdde_linux26 into libdde-linux26 to make dpkg-source happy

2 files changed, 0 insertions, 4671 deletions

diff --git a/libdde_linux26/lib/src/mm/memory.c b/libdde_linux26/lib/src/mm/memory.c
deleted file mode 100644
index a4d66f50..00000000
--- a/libdde_linux26/lib/src/mm/memory.c
+++ /dev/null
@@ -1,3203 +0,0 @@
-/*
- *  linux/mm/memory.c
- *
- *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
- */
-
-/*
- * demand-loading started 01.12.91 - seems it is high on the list of
- * things wanted, and it should be easy to implement. - Linus
- */
-
-/*
- * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
- * pages started 02.12.91, seems to work. - Linus.
- *
- * Tested sharing by executing about 30 /bin/sh: under the old kernel it
- * would have taken more than the 6M I have free, but it worked well as
- * far as I could see.
- *
- * Also corrected some "invalidate()"s - I wasn't doing enough of them.
- */
-
-/*
- * Real VM (paging to/from disk) started 18.12.91. Much more work and
- * thought has to go into this. Oh, well..
- * 19.12.91  -  works, somewhat. Sometimes I get faults, don't know why.
- *		Found it. Everything seems to work now.
- * 20.12.91  -  Ok, making the swap-device changeable like the root.
- */
-
-/*
- * 05.04.94  -  Multi-page memory management added for v1.1.
- * 		Idea by Alex Bligh (alex@cconcepts.co.uk)
- *
- * 16.07.99  -  Support of BIGMEM added by Gerhard Wichert, Siemens AG
- *		(Gerhard.Wichert@pdb.siemens.de)
- *
- * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
- */
-
-#include <linux/kernel_stat.h>
-#include <linux/mm.h>
-#include <linux/hugetlb.h>
-#include <linux/mman.h>
-#include <linux/swap.h>
-#include <linux/highmem.h>
-#include <linux/pagemap.h>
-#ifndef DDE_LINUX
-#include <linux/rmap.h>
-#endif
-#include <linux/module.h>
-#include <linux/delayacct.h>
-#include <linux/init.h>
-#include <linux/writeback.h>
-#include <linux/memcontrol.h>
-#include <linux/mmu_notifier.h>
-#include <linux/kallsyms.h>
-#include <linux/swapops.h>
-#include <linux/elf.h>
-
-#include <asm/pgalloc.h>
-#include <asm/uaccess.h>
-#include <asm/tlb.h>
-#include <asm/tlbflush.h>
-#include <asm/pgtable.h>
-
-#include "internal.h"
-
-#ifndef CONFIG_NEED_MULTIPLE_NODES
-/* use the per-pgdat data instead for discontigmem - mbligh */
-unsigned long max_mapnr;
-#ifndef DDE_LINUX
-struct page *mem_map;
-#endif
-
-EXPORT_SYMBOL(max_mapnr);
-#ifndef DDE_LINUX
-EXPORT_SYMBOL(mem_map);
-#endif
-#endif
-
-unsigned long num_physpages;
-/*
- * A number of key systems in x86 including ioremap() rely on the assumption
- * that high_memory defines the upper bound on direct map memory, then end
- * of ZONE_NORMAL.  Under CONFIG_DISCONTIG this means that max_low_pfn and
- * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
- * and ZONE_HIGHMEM.
- */
-void * high_memory;
-
-EXPORT_SYMBOL(num_physpages);
-EXPORT_SYMBOL(high_memory);
-
-/*
- * Randomize the address space (stacks, mmaps, brk, etc.).
- *
- * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
- *   as ancient (libc5 based) binaries can segfault. )
- */
-int randomize_va_space __read_mostly =
-#ifdef CONFIG_COMPAT_BRK
-					1;
-#else
-					2;
-#endif
-
-#ifndef DDE_LINUX
-static int __init disable_randmaps(char *s)
-{
-	randomize_va_space = 0;
-	return 1;
-}
-__setup("norandmaps", disable_randmaps);
-
-
-/*
- * If a p?d_bad entry is found while walking page tables, report
- * the error, before resetting entry to p?d_none.  Usually (but
- * very seldom) called out from the p?d_none_or_clear_bad macros.
- */
-
-void pgd_clear_bad(pgd_t *pgd)
-{
-	pgd_ERROR(*pgd);
-	pgd_clear(pgd);
-}
-
-void pud_clear_bad(pud_t *pud)
-{
-	pud_ERROR(*pud);
-	pud_clear(pud);
-}
-
-void pmd_clear_bad(pmd_t *pmd)
-{
-	pmd_ERROR(*pmd);
-	pmd_clear(pmd);
-}
-
-/*
- * Note: this doesn't free the actual pages themselves. That
- * has been handled earlier when unmapping all the memory regions.
- */
-static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
-{
-	pgtable_t token = pmd_pgtable(*pmd);
-	pmd_clear(pmd);
-	pte_free_tlb(tlb, token);
-	tlb->mm->nr_ptes--;
-}
-
-static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
-				unsigned long addr, unsigned long end,
-				unsigned long floor, unsigned long ceiling)
-{
-	pmd_t *pmd;
-	unsigned long next;
-	unsigned long start;
-
-	start = addr;
-	pmd = pmd_offset(pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (pmd_none_or_clear_bad(pmd))
-			continue;
-		free_pte_range(tlb, pmd);
-	} while (pmd++, addr = next, addr != end);
-
-	start &= PUD_MASK;
-	if (start < floor)
-		return;
-	if (ceiling) {
-		ceiling &= PUD_MASK;
-		if (!ceiling)
-			return;
-	}
-	if (end - 1 > ceiling - 1)
-		return;
-
-	pmd = pmd_offset(pud, start);
-	pud_clear(pud);
-	pmd_free_tlb(tlb, pmd);
-}
-
-static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
-				unsigned long addr, unsigned long end,
-				unsigned long floor, unsigned long ceiling)
-{
-	pud_t *pud;
-	unsigned long next;
-	unsigned long start;
-
-	start = addr;
-	pud = pud_offset(pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_none_or_clear_bad(pud))
-			continue;
-		free_pmd_range(tlb, pud, addr, next, floor, ceiling);
-	} while (pud++, addr = next, addr != end);
-
-	start &= PGDIR_MASK;
-	if (start < floor)
-		return;
-	if (ceiling) {
-		ceiling &= PGDIR_MASK;
-		if (!ceiling)
-			return;
-	}
-	if (end - 1 > ceiling - 1)
-		return;
-
-	pud = pud_offset(pgd, start);
-	pgd_clear(pgd);
-	pud_free_tlb(tlb, pud);
-}
-
-/*
- * This function frees user-level page tables of a process.
- *
- * Must be called with pagetable lock held.
- */
-void free_pgd_range(struct mmu_gather *tlb,
-			unsigned long addr, unsigned long end,
-			unsigned long floor, unsigned long ceiling)
-{
-	pgd_t *pgd;
-	unsigned long next;
-	unsigned long start;
-
-	/*
-	 * The next few lines have given us lots of grief...
-	 *
-	 * Why are we testing PMD* at this top level?  Because often
-	 * there will be no work to do at all, and we'd prefer not to
-	 * go all the way down to the bottom just to discover that.
-	 *
-	 * Why all these "- 1"s?  Because 0 represents both the bottom
-	 * of the address space and the top of it (using -1 for the
-	 * top wouldn't help much: the masks would do the wrong thing).
-	 * The rule is that addr 0 and floor 0 refer to the bottom of
-	 * the address space, but end 0 and ceiling 0 refer to the top
-	 * Comparisons need to use "end - 1" and "ceiling - 1" (though
-	 * that end 0 case should be mythical).
-	 *
-	 * Wherever addr is brought up or ceiling brought down, we must
-	 * be careful to reject "the opposite 0" before it confuses the
-	 * subsequent tests.  But what about where end is brought down
-	 * by PMD_SIZE below? no, end can't go down to 0 there.
-	 *
-	 * Whereas we round start (addr) and ceiling down, by different
-	 * masks at different levels, in order to test whether a table
-	 * now has no other vmas using it, so can be freed, we don't
-	 * bother to round floor or end up - the tests don't need that.
-	 */
-
-	addr &= PMD_MASK;
-	if (addr < floor) {
-		addr += PMD_SIZE;
-		if (!addr)
-			return;
-	}
-	if (ceiling) {
-		ceiling &= PMD_MASK;
-		if (!ceiling)
-			return;
-	}
-	if (end - 1 > ceiling - 1)
-		end -= PMD_SIZE;
-	if (addr > end - 1)
-		return;
-
-	start = addr;
-	pgd = pgd_offset(tlb->mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd))
-			continue;
-		free_pud_range(tlb, pgd, addr, next, floor, ceiling);
-	} while (pgd++, addr = next, addr != end);
-}
-
-void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
-		unsigned long floor, unsigned long ceiling)
-{
-	while (vma) {
-		struct vm_area_struct *next = vma->vm_next;
-		unsigned long addr = vma->vm_start;
-
-		/*
-		 * Hide vma from rmap and vmtruncate before freeing pgtables
-		 */
-		anon_vma_unlink(vma);
-		unlink_file_vma(vma);
-
-		if (is_vm_hugetlb_page(vma)) {
-			hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
-				floor, next? next->vm_start: ceiling);
-		} else {
-			/*
-			 * Optimization: gather nearby vmas into one call down
-			 */
-			while (next && next->vm_start <= vma->vm_end + PMD_SIZE
-			       && !is_vm_hugetlb_page(next)) {
-				vma = next;
-				next = vma->vm_next;
-				anon_vma_unlink(vma);
-				unlink_file_vma(vma);
-			}
-			free_pgd_range(tlb, addr, vma->vm_end,
-				floor, next? next->vm_start: ceiling);
-		}
-		vma = next;
-	}
-}
-
-int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
-{
-	pgtable_t new = pte_alloc_one(mm, address);
-	if (!new)
-		return -ENOMEM;
-
-	/*
-	 * Ensure all pte setup (eg. pte page lock and page clearing) are
-	 * visible before the pte is made visible to other CPUs by being
-	 * put into page tables.
-	 *
-	 * The other side of the story is the pointer chasing in the page
-	 * table walking code (when walking the page table without locking;
-	 * ie. most of the time). Fortunately, these data accesses consist
-	 * of a chain of data-dependent loads, meaning most CPUs (alpha
-	 * being the notable exception) will already guarantee loads are
-	 * seen in-order. See the alpha page table accessors for the
-	 * smp_read_barrier_depends() barriers in page table walking code.
-	 */
-	smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
-
-	spin_lock(&mm->page_table_lock);
-	if (!pmd_present(*pmd)) {	/* Has another populated it ? */
-		mm->nr_ptes++;
-		pmd_populate(mm, pmd, new);
-		new = NULL;
-	}
-	spin_unlock(&mm->page_table_lock);
-	if (new)
-		pte_free(mm, new);
-	return 0;
-}
-
-int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
-{
-	pte_t *new = pte_alloc_one_kernel(&init_mm, address);
-	if (!new)
-		return -ENOMEM;
-
-	smp_wmb(); /* See comment in __pte_alloc */
-
-	spin_lock(&init_mm.page_table_lock);
-	if (!pmd_present(*pmd)) {	/* Has another populated it ? */
-		pmd_populate_kernel(&init_mm, pmd, new);
-		new = NULL;
-	}
-	spin_unlock(&init_mm.page_table_lock);
-	if (new)
-		pte_free_kernel(&init_mm, new);
-	return 0;
-}
-
-static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
-{
-	if (file_rss)
-		add_mm_counter(mm, file_rss, file_rss);
-	if (anon_rss)
-		add_mm_counter(mm, anon_rss, anon_rss);
-}
-
-/*
- * This function is called to print an error when a bad pte
- * is found. For example, we might have a PFN-mapped pte in
- * a region that doesn't allow it.
- *
- * The calling function must still handle the error.
- */
-static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
-			  pte_t pte, struct page *page)
-{
-	pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
-	pud_t *pud = pud_offset(pgd, addr);
-	pmd_t *pmd = pmd_offset(pud, addr);
-	struct address_space *mapping;
-	pgoff_t index;
-	static unsigned long resume;
-	static unsigned long nr_shown;
-	static unsigned long nr_unshown;
-
-	/*
-	 * Allow a burst of 60 reports, then keep quiet for that minute;
-	 * or allow a steady drip of one report per second.
-	 */
-	if (nr_shown == 60) {
-		if (time_before(jiffies, resume)) {
-			nr_unshown++;
-			return;
-		}
-		if (nr_unshown) {
-			printk(KERN_ALERT
-				"BUG: Bad page map: %lu messages suppressed\n",
-				nr_unshown);
-			nr_unshown = 0;
-		}
-		nr_shown = 0;
-	}
-	if (nr_shown++ == 0)
-		resume = jiffies + 60 * HZ;
-
-	mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
-	index = linear_page_index(vma, addr);
-
-	printk(KERN_ALERT
-		"BUG: Bad page map in process %s  pte:%08llx pmd:%08llx\n",
-		current->comm,
-		(long long)pte_val(pte), (long long)pmd_val(*pmd));
-	if (page) {
-		printk(KERN_ALERT
-		"page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
-		page, (void *)page->flags, page_count(page),
-		page_mapcount(page), page->mapping, page->index);
-	}
-	printk(KERN_ALERT
-		"addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
-		(void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
-	/*
-	 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
-	 */
-	if (vma->vm_ops)
-		print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
-				(unsigned long)vma->vm_ops->fault);
-	if (vma->vm_file && vma->vm_file->f_op)
-		print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
-				(unsigned long)vma->vm_file->f_op->mmap);
-	dump_stack();
-	add_taint(TAINT_BAD_PAGE);
-}
-
-static inline int is_cow_mapping(unsigned int flags)
-{
-	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
-}
-
-/*
- * vm_normal_page -- This function gets the "struct page" associated with a pte.
- *
- * "Special" mappings do not wish to be associated with a "struct page" (either
- * it doesn't exist, or it exists but they don't want to touch it). In this
- * case, NULL is returned here. "Normal" mappings do have a struct page.
- *
- * There are 2 broad cases. Firstly, an architecture may define a pte_special()
- * pte bit, in which case this function is trivial. Secondly, an architecture
- * may not have a spare pte bit, which requires a more complicated scheme,
- * described below.
- *
- * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
- * special mapping (even if there are underlying and valid "struct pages").
- * COWed pages of a VM_PFNMAP are always normal.
- *
- * The way we recognize COWed pages within VM_PFNMAP mappings is through the
- * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
- * set, and the vm_pgoff will point to the first PFN mapped: thus every special
- * mapping will always honor the rule
- *
- *	pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
- *
- * And for normal mappings this is false.
- *
- * This restricts such mappings to be a linear translation from virtual address
- * to pfn. To get around this restriction, we allow arbitrary mappings so long
- * as the vma is not a COW mapping; in that case, we know that all ptes are
- * special (because none can have been COWed).
- *
- *
- * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
- *
- * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
- * page" backing, however the difference is that _all_ pages with a struct
- * page (that is, those where pfn_valid is true) are refcounted and considered
- * normal pages by the VM. The disadvantage is that pages are refcounted
- * (which can be slower and simply not an option for some PFNMAP users). The
- * advantage is that we don't have to follow the strict linearity rule of
- * PFNMAP mappings in order to support COWable mappings.
- *
- */
-#ifdef __HAVE_ARCH_PTE_SPECIAL
-# define HAVE_PTE_SPECIAL 1
-#else
-# define HAVE_PTE_SPECIAL 0
-#endif
-struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
-				pte_t pte)
-{
-	unsigned long pfn = pte_pfn(pte);
-
-	if (HAVE_PTE_SPECIAL) {
-		if (likely(!pte_special(pte)))
-			goto check_pfn;
-		if (!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)))
-			print_bad_pte(vma, addr, pte, NULL);
-		return NULL;
-	}
-
-	/* !HAVE_PTE_SPECIAL case follows: */
-
-	if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
-		if (vma->vm_flags & VM_MIXEDMAP) {
-			if (!pfn_valid(pfn))
-				return NULL;
-			goto out;
-		} else {
-			unsigned long off;
-			off = (addr - vma->vm_start) >> PAGE_SHIFT;
-			if (pfn == vma->vm_pgoff + off)
-				return NULL;
-			if (!is_cow_mapping(vma->vm_flags))
-				return NULL;
-		}
-	}
-
-check_pfn:
-	if (unlikely(pfn > highest_memmap_pfn)) {
-		print_bad_pte(vma, addr, pte, NULL);
-		return NULL;
-	}
-#endif
-
-	/*
-	 * NOTE! We still have PageReserved() pages in the page tables.
-	 * eg. VDSO mappings can cause them to exist.
-	 */
-out:
-	return pfn_to_page(pfn);
-}
-
-/*
- * copy one vm_area from one task to the other. Assumes the page tables
- * already present in the new task to be cleared in the whole range
- * covered by this vma.
- */
-
-static inline void
-copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
-		pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
-		unsigned long addr, int *rss)
-{
-	unsigned long vm_flags = vma->vm_flags;
-	pte_t pte = *src_pte;
-	struct page *page;
-
-	/* pte contains position in swap or file, so copy. */
-	if (unlikely(!pte_present(pte))) {
-		if (!pte_file(pte)) {
-			swp_entry_t entry = pte_to_swp_entry(pte);
-
-			swap_duplicate(entry);
-			/* make sure dst_mm is on swapoff's mmlist. */
-			if (unlikely(list_empty(&dst_mm->mmlist))) {
-				spin_lock(&mmlist_lock);
-				if (list_empty(&dst_mm->mmlist))
-					list_add(&dst_mm->mmlist,
-						 &src_mm->mmlist);
-				spin_unlock(&mmlist_lock);
-			}
-			if (is_write_migration_entry(entry) &&
-					is_cow_mapping(vm_flags)) {
-				/*
-				 * COW mappings require pages in both parent
-				 * and child to be set to read.
-				 */
-				make_migration_entry_read(&entry);
-				pte = swp_entry_to_pte(entry);
-				set_pte_at(src_mm, addr, src_pte, pte);
-			}
-		}
-		goto out_set_pte;
-	}
-
-	/*
-	 * If it's a COW mapping, write protect it both
-	 * in the parent and the child
-	 */
-	if (is_cow_mapping(vm_flags)) {
-		ptep_set_wrprotect(src_mm, addr, src_pte);
-		pte = pte_wrprotect(pte);
-	}
-
-	/*
-	 * If it's a shared mapping, mark it clean in
-	 * the child
-	 */
-	if (vm_flags & VM_SHARED)
-		pte = pte_mkclean(pte);
-	pte = pte_mkold(pte);
-
-	page = vm_normal_page(vma, addr, pte);
-	if (page) {
-		get_page(page);
-		page_dup_rmap(page, vma, addr);
-		rss[!!PageAnon(page)]++;
-	}
-
-out_set_pte:
-	set_pte_at(dst_mm, addr, dst_pte, pte);
-}
-
-static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
-		pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end)
-{
-	pte_t *src_pte, *dst_pte;
-	spinlock_t *src_ptl, *dst_ptl;
-	int progress = 0;
-	int rss[2];
-
-again:
-	rss[1] = rss[0] = 0;
-	dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
-	if (!dst_pte)
-		return -ENOMEM;
-	src_pte = pte_offset_map_nested(src_pmd, addr);
-	src_ptl = pte_lockptr(src_mm, src_pmd);
-	spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
-	arch_enter_lazy_mmu_mode();
-
-	do {
-		/*
-		 * We are holding two locks at this point - either of them
-		 * could generate latencies in another task on another CPU.
-		 */
-		if (progress >= 32) {
-			progress = 0;
-			if (need_resched() ||
-			    spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
-				break;
-		}
-		if (pte_none(*src_pte)) {
-			progress++;
-			continue;
-		}
-		copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
-		progress += 8;
-	} while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
-
-	arch_leave_lazy_mmu_mode();
-	spin_unlock(src_ptl);
-	pte_unmap_nested(src_pte - 1);
-	add_mm_rss(dst_mm, rss[0], rss[1]);
-	pte_unmap_unlock(dst_pte - 1, dst_ptl);
-	cond_resched();
-	if (addr != end)
-		goto again;
-	return 0;
-}
-
-static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
-		pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end)
-{
-	pmd_t *src_pmd, *dst_pmd;
-	unsigned long next;
-
-	dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
-	if (!dst_pmd)
-		return -ENOMEM;
-	src_pmd = pmd_offset(src_pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (pmd_none_or_clear_bad(src_pmd))
-			continue;
-		if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
-						vma, addr, next))
-			return -ENOMEM;
-	} while (dst_pmd++, src_pmd++, addr = next, addr != end);
-	return 0;
-}
-
-static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
-		pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end)
-{
-	pud_t *src_pud, *dst_pud;
-	unsigned long next;
-
-	dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
-	if (!dst_pud)
-		return -ENOMEM;
-	src_pud = pud_offset(src_pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_none_or_clear_bad(src_pud))
-			continue;
-		if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
-						vma, addr, next))
-			return -ENOMEM;
-	} while (dst_pud++, src_pud++, addr = next, addr != end);
-	return 0;
-}
-
-int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
-		struct vm_area_struct *vma)
-{
-	pgd_t *src_pgd, *dst_pgd;
-	unsigned long next;
-	unsigned long addr = vma->vm_start;
-	unsigned long end = vma->vm_end;
-	int ret;
-
-	/*
-	 * Don't copy ptes where a page fault will fill them correctly.
-	 * Fork becomes much lighter when there are big shared or private
-	 * readonly mappings. The tradeoff is that copy_page_range is more
-	 * efficient than faulting.
-	 */
-	if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
-		if (!vma->anon_vma)
-			return 0;
-	}
-
-	if (is_vm_hugetlb_page(vma))
-		return copy_hugetlb_page_range(dst_mm, src_mm, vma);
-
-	if (unlikely(is_pfn_mapping(vma))) {
-		/*
-		 * We do not free on error cases below as remove_vma
-		 * gets called on error from higher level routine
-		 */
-		ret = track_pfn_vma_copy(vma);
-		if (ret)
-			return ret;
-	}
-
-	/*
-	 * We need to invalidate the secondary MMU mappings only when
-	 * there could be a permission downgrade on the ptes of the
-	 * parent mm. And a permission downgrade will only happen if
-	 * is_cow_mapping() returns true.
-	 */
-	if (is_cow_mapping(vma->vm_flags))
-		mmu_notifier_invalidate_range_start(src_mm, addr, end);
-
-	ret = 0;
-	dst_pgd = pgd_offset(dst_mm, addr);
-	src_pgd = pgd_offset(src_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(src_pgd))
-			continue;
-		if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
-					    vma, addr, next))) {
-			ret = -ENOMEM;
-			break;
-		}
-	} while (dst_pgd++, src_pgd++, addr = next, addr != end);
-
-	if (is_cow_mapping(vma->vm_flags))
-		mmu_notifier_invalidate_range_end(src_mm,
-						  vma->vm_start, end);
-	return ret;
-}
-
-static unsigned long zap_pte_range(struct mmu_gather *tlb,
-				struct vm_area_struct *vma, pmd_t *pmd,
-				unsigned long addr, unsigned long end,
-				long *zap_work, struct zap_details *details)
-{
-	struct mm_struct *mm = tlb->mm;
-	pte_t *pte;
-	spinlock_t *ptl;
-	int file_rss = 0;
-	int anon_rss = 0;
-
-	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
-	arch_enter_lazy_mmu_mode();
-	do {
-		pte_t ptent = *pte;
-		if (pte_none(ptent)) {
-			(*zap_work)--;
-			continue;
-		}
-
-		(*zap_work) -= PAGE_SIZE;
-
-		if (pte_present(ptent)) {
-			struct page *page;
-
-			page = vm_normal_page(vma, addr, ptent);
-			if (unlikely(details) && page) {
-				/*
-				 * unmap_shared_mapping_pages() wants to
-				 * invalidate cache without truncating:
-				 * unmap shared but keep private pages.
-				 */
-				if (details->check_mapping &&
-				    details->check_mapping != page->mapping)
-					continue;
-				/*
-				 * Each page->index must be checked when
-				 * invalidating or truncating nonlinear.
-				 */
-				if (details->nonlinear_vma &&
-				    (page->index < details->first_index ||
-				     page->index > details->last_index))
-					continue;
-			}
-			ptent = ptep_get_and_clear_full(mm, addr, pte,
-							tlb->fullmm);
-			tlb_remove_tlb_entry(tlb, pte, addr);
-			if (unlikely(!page))
-				continue;
-			if (unlikely(details) && details->nonlinear_vma
-			    && linear_page_index(details->nonlinear_vma,
-						addr) != page->index)
-				set_pte_at(mm, addr, pte,
-					   pgoff_to_pte(page->index));
-			if (PageAnon(page))
-				anon_rss--;
-			else {
-				if (pte_dirty(ptent))
-					set_page_dirty(page);
-				if (pte_young(ptent) &&
-				    likely(!VM_SequentialReadHint(vma)))
-					mark_page_accessed(page);
-				file_rss--;
-			}
-			page_remove_rmap(page);
-			if (unlikely(page_mapcount(page) < 0))
-				print_bad_pte(vma, addr, ptent, page);
-			tlb_remove_page(tlb, page);
-			continue;
-		}
-		/*
-		 * If details->check_mapping, we leave swap entries;
-		 * if details->nonlinear_vma, we leave file entries.
-		 */
-		if (unlikely(details))
-			continue;
-		if (pte_file(ptent)) {
-			if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
-				print_bad_pte(vma, addr, ptent, NULL);
-		} else if
-		  (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent))))
-			print_bad_pte(vma, addr, ptent, NULL);
-		pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
-	} while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
-
-	add_mm_rss(mm, file_rss, anon_rss);
-	arch_leave_lazy_mmu_mode();
-	pte_unmap_unlock(pte - 1, ptl);
-
-	return addr;
-}
-
-static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
-				struct vm_area_struct *vma, pud_t *pud,
-				unsigned long addr, unsigned long end,
-				long *zap_work, struct zap_details *details)
-{
-	pmd_t *pmd;
-	unsigned long next;
-
-	pmd = pmd_offset(pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (pmd_none_or_clear_bad(pmd)) {
-			(*zap_work)--;
-			continue;
-		}
-		next = zap_pte_range(tlb, vma, pmd, addr, next,
-						zap_work, details);
-	} while (pmd++, addr = next, (addr != end && *zap_work > 0));
-
-	return addr;
-}
-
-static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
-				struct vm_area_struct *vma, pgd_t *pgd,
-				unsigned long addr, unsigned long end,
-				long *zap_work, struct zap_details *details)
-{
-	pud_t *pud;
-	unsigned long next;
-
-	pud = pud_offset(pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_none_or_clear_bad(pud)) {
-			(*zap_work)--;
-			continue;
-		}
-		next = zap_pmd_range(tlb, vma, pud, addr, next,
-						zap_work, details);
-	} while (pud++, addr = next, (addr != end && *zap_work > 0));
-
-	return addr;
-}
-
-static unsigned long unmap_page_range(struct mmu_gather *tlb,
-				struct vm_area_struct *vma,
-				unsigned long addr, unsigned long end,
-				long *zap_work, struct zap_details *details)
-{
-	pgd_t *pgd;
-	unsigned long next;
-
-	if (details && !details->check_mapping && !details->nonlinear_vma)
-		details = NULL;
-
-	BUG_ON(addr >= end);
-	tlb_start_vma(tlb, vma);
-	pgd = pgd_offset(vma->vm_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd)) {
-			(*zap_work)--;
-			continue;
-		}
-		next = zap_pud_range(tlb, vma, pgd, addr, next,
-						zap_work, details);
-	} while (pgd++, addr = next, (addr != end && *zap_work > 0));
-	tlb_end_vma(tlb, vma);
-
-	return addr;
-}
-
-#ifdef CONFIG_PREEMPT
-# define ZAP_BLOCK_SIZE	(8 * PAGE_SIZE)
-#else
-/* No preempt: go for improved straight-line efficiency */
-# define ZAP_BLOCK_SIZE	(1024 * PAGE_SIZE)
-#endif
-
-/**
- * unmap_vmas - unmap a range of memory covered by a list of vma's
- * @tlbp: address of the caller's struct mmu_gather
- * @vma: the starting vma
- * @start_addr: virtual address at which to start unmapping
- * @end_addr: virtual address at which to end unmapping
- * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
- * @details: details of nonlinear truncation or shared cache invalidation
- *
- * Returns the end address of the unmapping (restart addr if interrupted).
- *
- * Unmap all pages in the vma list.
- *
- * We aim to not hold locks for too long (for scheduling latency reasons).
- * So zap pages in ZAP_BLOCK_SIZE bytecounts.  This means we need to
- * return the ending mmu_gather to the caller.
- *
- * Only addresses between `start' and `end' will be unmapped.
- *
- * The VMA list must be sorted in ascending virtual address order.
- *
- * unmap_vmas() assumes that the caller will flush the whole unmapped address
- * range after unmap_vmas() returns.  So the only responsibility here is to
- * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
- * drops the lock and schedules.
- */
-unsigned long unmap_vmas(struct mmu_gather **tlbp,
-		struct vm_area_struct *vma, unsigned long start_addr,
-		unsigned long end_addr, unsigned long *nr_accounted,
-		struct zap_details *details)
-{
-	long zap_work = ZAP_BLOCK_SIZE;
-	unsigned long tlb_start = 0;	/* For tlb_finish_mmu */
-	int tlb_start_valid = 0;
-	unsigned long start = start_addr;
-	spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
-	int fullmm = (*tlbp)->fullmm;
-	struct mm_struct *mm = vma->vm_mm;
-
-	mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
-	for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
-		unsigned long end;
-
-		start = max(vma->vm_start, start_addr);
-		if (start >= vma->vm_end)
-			continue;
-		end = min(vma->vm_end, end_addr);
-		if (end <= vma->vm_start)
-			continue;
-
-		if (vma->vm_flags & VM_ACCOUNT)
-			*nr_accounted += (end - start) >> PAGE_SHIFT;
-
-		if (unlikely(is_pfn_mapping(vma)))
-			untrack_pfn_vma(vma, 0, 0);
-
-		while (start != end) {
-			if (!tlb_start_valid) {
-				tlb_start = start;
-				tlb_start_valid = 1;
-			}
-
-			if (unlikely(is_vm_hugetlb_page(vma))) {
-				/*
-				 * It is undesirable to test vma->vm_file as it
-				 * should be non-null for valid hugetlb area.
-				 * However, vm_file will be NULL in the error
-				 * cleanup path of do_mmap_pgoff. When
-				 * hugetlbfs ->mmap method fails,
-				 * do_mmap_pgoff() nullifies vma->vm_file
-				 * before calling this function to clean up.
-				 * Since no pte has actually been setup, it is
-				 * safe to do nothing in this case.
-				 */
-				if (vma->vm_file) {
-					unmap_hugepage_range(vma, start, end, NULL);
-					zap_work -= (end - start) /
-					pages_per_huge_page(hstate_vma(vma));
-				}
-
-				start = end;
-			} else
-				start = unmap_page_range(*tlbp, vma,
-						start, end, &zap_work, details);
-
-			if (zap_work > 0) {
-				BUG_ON(start != end);
-				break;
-			}
-
-			tlb_finish_mmu(*tlbp, tlb_start, start);
-
-			if (need_resched() ||
-				(i_mmap_lock && spin_needbreak(i_mmap_lock))) {
-				if (i_mmap_lock) {
-					*tlbp = NULL;
-					goto out;
-				}
-				cond_resched();
-			}
-
-			*tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
-			tlb_start_valid = 0;
-			zap_work = ZAP_BLOCK_SIZE;
-		}
-	}
-out:
-	mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
-	return start;	/* which is now the end (or restart) address */
-}
-
-/**
- * zap_page_range - remove user pages in a given range
- * @vma: vm_area_struct holding the applicable pages
- * @address: starting address of pages to zap
- * @size: number of bytes to zap
- * @details: details of nonlinear truncation or shared cache invalidation
- */
-unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
-		unsigned long size, struct zap_details *details)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	struct mmu_gather *tlb;
-	unsigned long end = address + size;
-	unsigned long nr_accounted = 0;
-
-	lru_add_drain();
-	tlb = tlb_gather_mmu(mm, 0);
-	update_hiwater_rss(mm);
-	end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
-	if (tlb)
-		tlb_finish_mmu(tlb, address, end);
-	return end;
-}
-
-/**
- * zap_vma_ptes - remove ptes mapping the vma
- * @vma: vm_area_struct holding ptes to be zapped
- * @address: starting address of pages to zap
- * @size: number of bytes to zap
- *
- * This function only unmaps ptes assigned to VM_PFNMAP vmas.
- *
- * The entire address range must be fully contained within the vma.
- *
- * Returns 0 if successful.
- */
-int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
-		unsigned long size)
-{
-	if (address < vma->vm_start || address + size > vma->vm_end ||
-	    		!(vma->vm_flags & VM_PFNMAP))
-		return -1;
-	zap_page_range(vma, address, size, NULL);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(zap_vma_ptes);
-
-/*
- * Do a quick page-table lookup for a single page.
- */
-struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
-			unsigned int flags)
-{
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *ptep, pte;
-	spinlock_t *ptl;
-	struct page *page;
-	struct mm_struct *mm = vma->vm_mm;
-
-	page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
-	if (!IS_ERR(page)) {
-		BUG_ON(flags & FOLL_GET);
-		goto out;
-	}
-
-	page = NULL;
-	pgd = pgd_offset(mm, address);
-	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
-		goto no_page_table;
-
-	pud = pud_offset(pgd, address);
-	if (pud_none(*pud))
-		goto no_page_table;
-	if (pud_huge(*pud)) {
-		BUG_ON(flags & FOLL_GET);
-		page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
-		goto out;
-	}
-	if (unlikely(pud_bad(*pud)))
-		goto no_page_table;
-
-	pmd = pmd_offset(pud, address);
-	if (pmd_none(*pmd))
-		goto no_page_table;
-	if (pmd_huge(*pmd)) {
-		BUG_ON(flags & FOLL_GET);
-		page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
-		goto out;
-	}
-	if (unlikely(pmd_bad(*pmd)))
-		goto no_page_table;
-
-	ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
-
-	pte = *ptep;
-	if (!pte_present(pte))
-		goto no_page;
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
-		goto unlock;
-	page = vm_normal_page(vma, address, pte);
-	if (unlikely(!page))
-		goto bad_page;
-
-	if (flags & FOLL_GET)
-		get_page(page);
-	if (flags & FOLL_TOUCH) {
-		if ((flags & FOLL_WRITE) &&
-		    !pte_dirty(pte) && !PageDirty(page))
-			set_page_dirty(page);
-		mark_page_accessed(page);
-	}
-unlock:
-	pte_unmap_unlock(ptep, ptl);
-out:
-	return page;
-
-bad_page:
-	pte_unmap_unlock(ptep, ptl);
-	return ERR_PTR(-EFAULT);
-
-no_page:
-	pte_unmap_unlock(ptep, ptl);
-	if (!pte_none(pte))
-		return page;
-	/* Fall through to ZERO_PAGE handling */
-no_page_table:
-	/*
-	 * When core dumping an enormous anonymous area that nobody
-	 * has touched so far, we don't want to allocate page tables.
-	 */
-	if (flags & FOLL_ANON) {
-		page = ZERO_PAGE(0);
-		if (flags & FOLL_GET)
-			get_page(page);
-		BUG_ON(flags & FOLL_WRITE);
-	}
-	return page;
-}
-
-/* Can we do the FOLL_ANON optimization? */
-static inline int use_zero_page(struct vm_area_struct *vma)
-{
-	/*
-	 * We don't want to optimize FOLL_ANON for make_pages_present()
-	 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
-	 * we want to get the page from the page tables to make sure
-	 * that we serialize and update with any other user of that
-	 * mapping.
-	 */
-	if (vma->vm_flags & (VM_LOCKED | VM_SHARED))
-		return 0;
-	/*
-	 * And if we have a fault routine, it's not an anonymous region.
-	 */
-	return !vma->vm_ops || !vma->vm_ops->fault;
-}
-
-
-
-int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-		     unsigned long start, int len, int flags,
-		struct page **pages, struct vm_area_struct **vmas)
-{
-	int i;
-	unsigned int vm_flags = 0;
-	int write = !!(flags & GUP_FLAGS_WRITE);
-	int force = !!(flags & GUP_FLAGS_FORCE);
-	int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
-	int ignore_sigkill = !!(flags & GUP_FLAGS_IGNORE_SIGKILL);
-
-	if (len <= 0)
-		return 0;
-	/* 
-	 * Require read or write permissions.
-	 * If 'force' is set, we only require the "MAY" flags.
-	 */
-	vm_flags  = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
-	vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
-	i = 0;
-
-	do {
-		struct vm_area_struct *vma;
-		unsigned int foll_flags;
-
-		vma = find_extend_vma(mm, start);
-		if (!vma && in_gate_area(tsk, start)) {
-			unsigned long pg = start & PAGE_MASK;
-			struct vm_area_struct *gate_vma = get_gate_vma(tsk);
-			pgd_t *pgd;
-			pud_t *pud;
-			pmd_t *pmd;
-			pte_t *pte;
-
-			/* user gate pages are read-only */
-			if (!ignore && write)
-				return i ? : -EFAULT;
-			if (pg > TASK_SIZE)
-				pgd = pgd_offset_k(pg);
-			else
-				pgd = pgd_offset_gate(mm, pg);
-			BUG_ON(pgd_none(*pgd));
-			pud = pud_offset(pgd, pg);
-			BUG_ON(pud_none(*pud));
-			pmd = pmd_offset(pud, pg);
-			if (pmd_none(*pmd))
-				return i ? : -EFAULT;
-			pte = pte_offset_map(pmd, pg);
-			if (pte_none(*pte)) {
-				pte_unmap(pte);
-				return i ? : -EFAULT;
-			}
-			if (pages) {
-				struct page *page = vm_normal_page(gate_vma, start, *pte);
-				pages[i] = page;
-				if (page)
-					get_page(page);
-			}
-			pte_unmap(pte);
-			if (vmas)
-				vmas[i] = gate_vma;
-			i++;
-			start += PAGE_SIZE;
-			len--;
-			continue;
-		}
-
-		if (!vma ||
-		    (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
-		    (!ignore && !(vm_flags & vma->vm_flags)))
-			return i ? : -EFAULT;
-
-		if (is_vm_hugetlb_page(vma)) {
-			i = follow_hugetlb_page(mm, vma, pages, vmas,
-						&start, &len, i, write);
-			continue;
-		}
-
-		foll_flags = FOLL_TOUCH;
-		if (pages)
-			foll_flags |= FOLL_GET;
-		if (!write && use_zero_page(vma))
-			foll_flags |= FOLL_ANON;
-
-		do {
-			struct page *page;
-
-			/*
-			 * If we have a pending SIGKILL, don't keep faulting
-			 * pages and potentially allocating memory, unless
-			 * current is handling munlock--e.g., on exit. In
-			 * that case, we are not allocating memory.  Rather,
-			 * we're only unlocking already resident/mapped pages.
-			 */
-			if (unlikely(!ignore_sigkill &&
-					fatal_signal_pending(current)))
-				return i ? i : -ERESTARTSYS;
-
-			if (write)
-				foll_flags |= FOLL_WRITE;
-
-			cond_resched();
-			while (!(page = follow_page(vma, start, foll_flags))) {
-				int ret;
-				ret = handle_mm_fault(mm, vma, start,
-						foll_flags & FOLL_WRITE);
-				if (ret & VM_FAULT_ERROR) {
-					if (ret & VM_FAULT_OOM)
-						return i ? i : -ENOMEM;
-					else if (ret & VM_FAULT_SIGBUS)
-						return i ? i : -EFAULT;
-					BUG();
-				}
-				if (ret & VM_FAULT_MAJOR)
-					tsk->maj_flt++;
-				else
-					tsk->min_flt++;
-
-				/*
-				 * The VM_FAULT_WRITE bit tells us that
-				 * do_wp_page has broken COW when necessary,
-				 * even if maybe_mkwrite decided not to set
-				 * pte_write. We can thus safely do subsequent
-				 * page lookups as if they were reads. But only
-				 * do so when looping for pte_write is futile:
-				 * in some cases userspace may also be wanting
-				 * to write to the gotten user page, which a
-				 * read fault here might prevent (a readonly
-				 * page might get reCOWed by userspace write).
-				 */
-				if ((ret & VM_FAULT_WRITE) &&
-				    !(vma->vm_flags & VM_WRITE))
-					foll_flags &= ~FOLL_WRITE;
-
-				cond_resched();
-			}
-			if (IS_ERR(page))
-				return i ? i : PTR_ERR(page);
-			if (pages) {
-				pages[i] = page;
-
-				flush_anon_page(vma, page, start);
-				flush_dcache_page(page);
-			}
-			if (vmas)
-				vmas[i] = vma;
-			i++;
-			start += PAGE_SIZE;
-			len--;
-		} while (len && start < vma->vm_end);
-	} while (len);
-	return i;
-}
-
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-		unsigned long start, int len, int write, int force,
-		struct page **pages, struct vm_area_struct **vmas)
-{
-	int flags = 0;
-
-	if (write)
-		flags |= GUP_FLAGS_WRITE;
-	if (force)
-		flags |= GUP_FLAGS_FORCE;
-
-	return __get_user_pages(tsk, mm,
-				start, len, flags,
-				pages, vmas);
-}
-
-EXPORT_SYMBOL(get_user_pages);
-
-pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
-			spinlock_t **ptl)
-{
-	pgd_t * pgd = pgd_offset(mm, addr);
-	pud_t * pud = pud_alloc(mm, pgd, addr);
-	if (pud) {
-		pmd_t * pmd = pmd_alloc(mm, pud, addr);
-		if (pmd)
-			return pte_alloc_map_lock(mm, pmd, addr, ptl);
-	}
-	return NULL;
-}
-
-/*
- * This is the old fallback for page remapping.
- *
- * For historical reasons, it only allows reserved pages. Only
- * old drivers should use this, and they needed to mark their
- * pages reserved for the old functions anyway.
- */
-static int insert_page(struct vm_area_struct *vma, unsigned long addr,
-			struct page *page, pgprot_t prot)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	int retval;
-	pte_t *pte;
-	spinlock_t *ptl;
-
-	retval = -EINVAL;
-	if (PageAnon(page))
-		goto out;
-	retval = -ENOMEM;
-	flush_dcache_page(page);
-	pte = get_locked_pte(mm, addr, &ptl);
-	if (!pte)
-		goto out;
-	retval = -EBUSY;
-	if (!pte_none(*pte))
-		goto out_unlock;
-
-	/* Ok, finally just insert the thing.. */
-	get_page(page);
-	inc_mm_counter(mm, file_rss);
-	page_add_file_rmap(page);
-	set_pte_at(mm, addr, pte, mk_pte(page, prot));
-
-	retval = 0;
-	pte_unmap_unlock(pte, ptl);
-	return retval;
-out_unlock:
-	pte_unmap_unlock(pte, ptl);
-out:
-	return retval;
-}
-
-/**
- * vm_insert_page - insert single page into user vma
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @page: source kernel page
- *
- * This allows drivers to insert individual pages they've allocated
- * into a user vma.
- *
- * The page has to be a nice clean _individual_ kernel allocation.
- * If you allocate a compound page, you need to have marked it as
- * such (__GFP_COMP), or manually just split the page up yourself
- * (see split_page()).
- *
- * NOTE! Traditionally this was done with "remap_pfn_range()" which
- * took an arbitrary page protection parameter. This doesn't allow
- * that. Your vma protection will have to be set up correctly, which
- * means that if you want a shared writable mapping, you'd better
- * ask for a shared writable mapping!
- *
- * The page does not need to be reserved.
- */
-int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
-			struct page *page)
-{
-	if (addr < vma->vm_start || addr >= vma->vm_end)
-		return -EFAULT;
-	if (!page_count(page))
-		return -EINVAL;
-	vma->vm_flags |= VM_INSERTPAGE;
-	return insert_page(vma, addr, page, vma->vm_page_prot);
-}
-EXPORT_SYMBOL(vm_insert_page);
-
-static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
-			unsigned long pfn, pgprot_t prot)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	int retval;
-	pte_t *pte, entry;
-	spinlock_t *ptl;
-
-	retval = -ENOMEM;
-	pte = get_locked_pte(mm, addr, &ptl);
-	if (!pte)
-		goto out;
-	retval = -EBUSY;
-	if (!pte_none(*pte))
-		goto out_unlock;
-
-	/* Ok, finally just insert the thing.. */
-	entry = pte_mkspecial(pfn_pte(pfn, prot));
-	set_pte_at(mm, addr, pte, entry);
-	update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
-
-	retval = 0;
-out_unlock:
-	pte_unmap_unlock(pte, ptl);
-out:
-	return retval;
-}
-
-/**
- * vm_insert_pfn - insert single pfn into user vma
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @pfn: source kernel pfn
- *
- * Similar to vm_inert_page, this allows drivers to insert individual pages
- * they've allocated into a user vma. Same comments apply.
- *
- * This function should only be called from a vm_ops->fault handler, and
- * in that case the handler should return NULL.
- *
- * vma cannot be a COW mapping.
- *
- * As this is called only for pages that do not currently exist, we
- * do not need to flush old virtual caches or the TLB.
- */
-int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
-			unsigned long pfn)
-{
-	int ret;
-	pgprot_t pgprot = vma->vm_page_prot;
-	/*
-	 * Technically, architectures with pte_special can avoid all these
-	 * restrictions (same for remap_pfn_range).  However we would like
-	 * consistency in testing and feature parity among all, so we should
-	 * try to keep these invariants in place for everybody.
-	 */
-	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
-	BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
-						(VM_PFNMAP|VM_MIXEDMAP));
-	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
-	BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
-
-	if (addr < vma->vm_start || addr >= vma->vm_end)
-		return -EFAULT;
-	if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
-		return -EINVAL;
-
-	ret = insert_pfn(vma, addr, pfn, pgprot);
-
-	if (ret)
-		untrack_pfn_vma(vma, pfn, PAGE_SIZE);
-
-	return ret;
-}
-EXPORT_SYMBOL(vm_insert_pfn);
-
-int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
-			unsigned long pfn)
-{
-	BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
-
-	if (addr < vma->vm_start || addr >= vma->vm_end)
-		return -EFAULT;
-
-	/*
-	 * If we don't have pte special, then we have to use the pfn_valid()
-	 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
-	 * refcount the page if pfn_valid is true (hence insert_page rather
-	 * than insert_pfn).
-	 */
-	if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
-		struct page *page;
-
-		page = pfn_to_page(pfn);
-		return insert_page(vma, addr, page, vma->vm_page_prot);
-	}
-	return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
-}
-EXPORT_SYMBOL(vm_insert_mixed);
-
-/*
- * maps a range of physical memory into the requested pages. the old
- * mappings are removed. any references to nonexistent pages results
- * in null mappings (currently treated as "copy-on-access")
- */
-static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
-			unsigned long addr, unsigned long end,
-			unsigned long pfn, pgprot_t prot)
-{
-	pte_t *pte;
-	spinlock_t *ptl;
-
-	pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
-	if (!pte)
-		return -ENOMEM;
-	arch_enter_lazy_mmu_mode();
-	do {
-		BUG_ON(!pte_none(*pte));
-		set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
-		pfn++;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
-	arch_leave_lazy_mmu_mode();
-	pte_unmap_unlock(pte - 1, ptl);
-	return 0;
-}
-
-static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
-			unsigned long addr, unsigned long end,
-			unsigned long pfn, pgprot_t prot)
-{
-	pmd_t *pmd;
-	unsigned long next;
-
-	pfn -= addr >> PAGE_SHIFT;
-	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd)
-		return -ENOMEM;
-	do {
-		next = pmd_addr_end(addr, end);
-		if (remap_pte_range(mm, pmd, addr, next,
-				pfn + (addr >> PAGE_SHIFT), prot))
-			return -ENOMEM;
-	} while (pmd++, addr = next, addr != end);
-	return 0;
-}
-
-static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
-			unsigned long addr, unsigned long end,
-			unsigned long pfn, pgprot_t prot)
-{
-	pud_t *pud;
-	unsigned long next;
-
-	pfn -= addr >> PAGE_SHIFT;
-	pud = pud_alloc(mm, pgd, addr);
-	if (!pud)
-		return -ENOMEM;
-	do {
-		next = pud_addr_end(addr, end);
-		if (remap_pmd_range(mm, pud, addr, next,
-				pfn + (addr >> PAGE_SHIFT), prot))
-			return -ENOMEM;
-	} while (pud++, addr = next, addr != end);
-	return 0;
-}
-
-/**
- * remap_pfn_range - remap kernel memory to userspace
- * @vma: user vma to map to
- * @addr: target user address to start at
- * @pfn: physical address of kernel memory
- * @size: size of map area
- * @prot: page protection flags for this mapping
- *
- *  Note: this is only safe if the mm semaphore is held when called.
- */
-int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
-		    unsigned long pfn, unsigned long size, pgprot_t prot)
-{
-	pgd_t *pgd;
-	unsigned long next;
-	unsigned long end = addr + PAGE_ALIGN(size);
-	struct mm_struct *mm = vma->vm_mm;
-	int err;
-
-	/*
-	 * Physically remapped pages are special. Tell the
-	 * rest of the world about it:
-	 *   VM_IO tells people not to look at these pages
-	 *	(accesses can have side effects).
-	 *   VM_RESERVED is specified all over the place, because
-	 *	in 2.4 it kept swapout's vma scan off this vma; but
-	 *	in 2.6 the LRU scan won't even find its pages, so this
-	 *	flag means no more than count its pages in reserved_vm,
-	 * 	and omit it from core dump, even when VM_IO turned off.
-	 *   VM_PFNMAP tells the core MM that the base pages are just
-	 *	raw PFN mappings, and do not have a "struct page" associated
-	 *	with them.
-	 *
-	 * There's a horrible special case to handle copy-on-write
-	 * behaviour that some programs depend on. We mark the "original"
-	 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
-	 */
-	if (addr == vma->vm_start && end == vma->vm_end)
-		vma->vm_pgoff = pfn;
-	else if (is_cow_mapping(vma->vm_flags))
-		return -EINVAL;
-
-	vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
-
-	err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
-	if (err) {
-		/*
-		 * To indicate that track_pfn related cleanup is not
-		 * needed from higher level routine calling unmap_vmas
-		 */
-		vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
-		return -EINVAL;
-	}
-
-	BUG_ON(addr >= end);
-	pfn -= addr >> PAGE_SHIFT;
-	pgd = pgd_offset(mm, addr);
-	flush_cache_range(vma, addr, end);
-	do {
-		next = pgd_addr_end(addr, end);
-		err = remap_pud_range(mm, pgd, addr, next,
-				pfn + (addr >> PAGE_SHIFT), prot);
-		if (err)
-			break;
-	} while (pgd++, addr = next, addr != end);
-
-	if (err)
-		untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
-
-	return err;
-}
-EXPORT_SYMBOL(remap_pfn_range);
-
-static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
-				     unsigned long addr, unsigned long end,
-				     pte_fn_t fn, void *data)
-{
-	pte_t *pte;
-	int err;
-	pgtable_t token;
-	spinlock_t *uninitialized_var(ptl);
-
-	pte = (mm == &init_mm) ?
-		pte_alloc_kernel(pmd, addr) :
-		pte_alloc_map_lock(mm, pmd, addr, &ptl);
-	if (!pte)
-		return -ENOMEM;
-
-	BUG_ON(pmd_huge(*pmd));
-
-	arch_enter_lazy_mmu_mode();
-
-	token = pmd_pgtable(*pmd);
-
-	do {
-		err = fn(pte, token, addr, data);
-		if (err)
-			break;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
-
-	arch_leave_lazy_mmu_mode();
-
-	if (mm != &init_mm)
-		pte_unmap_unlock(pte-1, ptl);
-	return err;
-}
-
-static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
-				     unsigned long addr, unsigned long end,
-				     pte_fn_t fn, void *data)
-{
-	pmd_t *pmd;
-	unsigned long next;
-	int err;
-
-	BUG_ON(pud_huge(*pud));
-
-	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd)
-		return -ENOMEM;
-	do {
-		next = pmd_addr_end(addr, end);
-		err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
-		if (err)
-			break;
-	} while (pmd++, addr = next, addr != end);
-	return err;
-}
-
-static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
-				     unsigned long addr, unsigned long end,
-				     pte_fn_t fn, void *data)
-{
-	pud_t *pud;
-	unsigned long next;
-	int err;
-
-	pud = pud_alloc(mm, pgd, addr);
-	if (!pud)
-		return -ENOMEM;
-	do {
-		next = pud_addr_end(addr, end);
-		err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
-		if (err)
-			break;
-	} while (pud++, addr = next, addr != end);
-	return err;
-}
-
-/*
- * Scan a region of virtual memory, filling in page tables as necessary
- * and calling a provided function on each leaf page table.
- */
-int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
-			unsigned long size, pte_fn_t fn, void *data)
-{
-	pgd_t *pgd;
-	unsigned long next;
-	unsigned long start = addr, end = addr + size;
-	int err;
-
-	BUG_ON(addr >= end);
-	mmu_notifier_invalidate_range_start(mm, start, end);
-	pgd = pgd_offset(mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
-		if (err)
-			break;
-	} while (pgd++, addr = next, addr != end);
-	mmu_notifier_invalidate_range_end(mm, start, end);
-	return err;
-}
-EXPORT_SYMBOL_GPL(apply_to_page_range);
-
-/*
- * handle_pte_fault chooses page fault handler according to an entry
- * which was read non-atomically.  Before making any commitment, on
- * those architectures or configurations (e.g. i386 with PAE) which
- * might give a mix of unmatched parts, do_swap_page and do_file_page
- * must check under lock before unmapping the pte and proceeding
- * (but do_wp_page is only called after already making such a check;
- * and do_anonymous_page and do_no_page can safely check later on).
- */
-static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
-				pte_t *page_table, pte_t orig_pte)
-{
-	int same = 1;
-#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
-	if (sizeof(pte_t) > sizeof(unsigned long)) {
-		spinlock_t *ptl = pte_lockptr(mm, pmd);
-		spin_lock(ptl);
-		same = pte_same(*page_table, orig_pte);
-		spin_unlock(ptl);
-	}
-#endif
-	pte_unmap(page_table);
-	return same;
-}
-
-/*
- * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
- * servicing faults for write access.  In the normal case, do always want
- * pte_mkwrite.  But get_user_pages can cause write faults for mappings
- * that do not have writing enabled, when used by access_process_vm.
- */
-static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
-{
-	if (likely(vma->vm_flags & VM_WRITE))
-		pte = pte_mkwrite(pte);
-	return pte;
-}
-
-static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
-{
-	/*
-	 * If the source page was a PFN mapping, we don't have
-	 * a "struct page" for it. We do a best-effort copy by
-	 * just copying from the original user address. If that
-	 * fails, we just zero-fill it. Live with it.
-	 */
-	if (unlikely(!src)) {
-		void *kaddr = kmap_atomic(dst, KM_USER0);
-		void __user *uaddr = (void __user *)(va & PAGE_MASK);
-
-		/*
-		 * This really shouldn't fail, because the page is there
-		 * in the page tables. But it might just be unreadable,
-		 * in which case we just give up and fill the result with
-		 * zeroes.
-		 */
-		if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
-			memset(kaddr, 0, PAGE_SIZE);
-		kunmap_atomic(kaddr, KM_USER0);
-		flush_dcache_page(dst);
-	} else
-		copy_user_highpage(dst, src, va, vma);
-}
-
-/*
- * This routine handles present pages, when users try to write
- * to a shared page. It is done by copying the page to a new address
- * and decrementing the shared-page counter for the old page.
- *
- * Note that this routine assumes that the protection checks have been
- * done by the caller (the low-level page fault routine in most cases).
- * Thus we can safely just mark it writable once we've done any necessary
- * COW.
- *
- * We also mark the page dirty at this point even though the page will
- * change only once the write actually happens. This avoids a few races,
- * and potentially makes it more efficient.
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), with pte both mapped and locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- */
-static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		spinlock_t *ptl, pte_t orig_pte)
-{
-	struct page *old_page, *new_page;
-	pte_t entry;
-	int reuse = 0, ret = 0;
-	int page_mkwrite = 0;
-	struct page *dirty_page = NULL;
-
-	old_page = vm_normal_page(vma, address, orig_pte);
-	if (!old_page) {
-		/*
-		 * VM_MIXEDMAP !pfn_valid() case
-		 *
-		 * We should not cow pages in a shared writeable mapping.
-		 * Just mark the pages writable as we can't do any dirty
-		 * accounting on raw pfn maps.
-		 */
-		if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
-				     (VM_WRITE|VM_SHARED))
-			goto reuse;
-		goto gotten;
-	}
-
-	/*
-	 * Take out anonymous pages first, anonymous shared vmas are
-	 * not dirty accountable.
-	 */
-	if (PageAnon(old_page)) {
-		if (!trylock_page(old_page)) {
-			page_cache_get(old_page);
-			pte_unmap_unlock(page_table, ptl);
-			lock_page(old_page);
-			page_table = pte_offset_map_lock(mm, pmd, address,
-							 &ptl);
-			if (!pte_same(*page_table, orig_pte)) {
-				unlock_page(old_page);
-				page_cache_release(old_page);
-				goto unlock;
-			}
-			page_cache_release(old_page);
-		}
-		reuse = reuse_swap_page(old_page);
-		unlock_page(old_page);
-	} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
-					(VM_WRITE|VM_SHARED))) {
-		/*
-		 * Only catch write-faults on shared writable pages,
-		 * read-only shared pages can get COWed by
-		 * get_user_pages(.write=1, .force=1).
-		 */
-		if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
-			/*
-			 * Notify the address space that the page is about to
-			 * become writable so that it can prohibit this or wait
-			 * for the page to get into an appropriate state.
-			 *
-			 * We do this without the lock held, so that it can
-			 * sleep if it needs to.
-			 */
-			page_cache_get(old_page);
-			pte_unmap_unlock(page_table, ptl);
-
-			if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
-				goto unwritable_page;
-
-			/*
-			 * Since we dropped the lock we need to revalidate
-			 * the PTE as someone else may have changed it.  If
-			 * they did, we just return, as we can count on the
-			 * MMU to tell us if they didn't also make it writable.
-			 */
-			page_table = pte_offset_map_lock(mm, pmd, address,
-							 &ptl);
-			page_cache_release(old_page);
-			if (!pte_same(*page_table, orig_pte))
-				goto unlock;
-
-			page_mkwrite = 1;
-		}
-		dirty_page = old_page;
-		get_page(dirty_page);
-		reuse = 1;
-	}
-
-	if (reuse) {
-reuse:
-		flush_cache_page(vma, address, pte_pfn(orig_pte));
-		entry = pte_mkyoung(orig_pte);
-		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-		if (ptep_set_access_flags(vma, address, page_table, entry,1))
-			update_mmu_cache(vma, address, entry);
-		ret |= VM_FAULT_WRITE;
-		goto unlock;
-	}
-
-	/*
-	 * Ok, we need to copy. Oh, well..
-	 */
-	page_cache_get(old_page);
-gotten:
-	pte_unmap_unlock(page_table, ptl);
-
-	if (unlikely(anon_vma_prepare(vma)))
-		goto oom;
-	VM_BUG_ON(old_page == ZERO_PAGE(0));
-	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
-	if (!new_page)
-		goto oom;
-	/*
-	 * Don't let another task, with possibly unlocked vma,
-	 * keep the mlocked page.
-	 */
-	if ((vma->vm_flags & VM_LOCKED) && old_page) {
-		lock_page(old_page);	/* for LRU manipulation */
-		clear_page_mlock(old_page);
-		unlock_page(old_page);
-	}
-	cow_user_page(new_page, old_page, address, vma);
-	__SetPageUptodate(new_page);
-
-	if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
-		goto oom_free_new;
-
-	/*
-	 * Re-check the pte - we dropped the lock
-	 */
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (likely(pte_same(*page_table, orig_pte))) {
-		if (old_page) {
-			if (!PageAnon(old_page)) {
-				dec_mm_counter(mm, file_rss);
-				inc_mm_counter(mm, anon_rss);
-			}
-		} else
-			inc_mm_counter(mm, anon_rss);
-		flush_cache_page(vma, address, pte_pfn(orig_pte));
-		entry = mk_pte(new_page, vma->vm_page_prot);
-		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-		/*
-		 * Clear the pte entry and flush it first, before updating the
-		 * pte with the new entry. This will avoid a race condition
-		 * seen in the presence of one thread doing SMC and another
-		 * thread doing COW.
-		 */
-		ptep_clear_flush_notify(vma, address, page_table);
-		page_add_new_anon_rmap(new_page, vma, address);
-		set_pte_at(mm, address, page_table, entry);
-		update_mmu_cache(vma, address, entry);
-		if (old_page) {
-			/*
-			 * Only after switching the pte to the new page may
-			 * we remove the mapcount here. Otherwise another
-			 * process may come and find the rmap count decremented
-			 * before the pte is switched to the new page, and
-			 * "reuse" the old page writing into it while our pte
-			 * here still points into it and can be read by other
-			 * threads.
-			 *
-			 * The critical issue is to order this
-			 * page_remove_rmap with the ptp_clear_flush above.
-			 * Those stores are ordered by (if nothing else,)
-			 * the barrier present in the atomic_add_negative
-			 * in page_remove_rmap.
-			 *
-			 * Then the TLB flush in ptep_clear_flush ensures that
-			 * no process can access the old page before the
-			 * decremented mapcount is visible. And the old page
-			 * cannot be reused until after the decremented
-			 * mapcount is visible. So transitively, TLBs to
-			 * old page will be flushed before it can be reused.
-			 */
-			page_remove_rmap(old_page);
-		}
-
-		/* Free the old page.. */
-		new_page = old_page;
-		ret |= VM_FAULT_WRITE;
-	} else
-		mem_cgroup_uncharge_page(new_page);
-
-	if (new_page)
-		page_cache_release(new_page);
-	if (old_page)
-		page_cache_release(old_page);
-unlock:
-	pte_unmap_unlock(page_table, ptl);
-	if (dirty_page) {
-		if (vma->vm_file)
-			file_update_time(vma->vm_file);
-
-		/*
-		 * Yes, Virginia, this is actually required to prevent a race
-		 * with clear_page_dirty_for_io() from clearing the page dirty
-		 * bit after it clear all dirty ptes, but before a racing
-		 * do_wp_page installs a dirty pte.
-		 *
-		 * do_no_page is protected similarly.
-		 */
-		wait_on_page_locked(dirty_page);
-		set_page_dirty_balance(dirty_page, page_mkwrite);
-		put_page(dirty_page);
-	}
-	return ret;
-oom_free_new:
-	page_cache_release(new_page);
-oom:
-	if (old_page)
-		page_cache_release(old_page);
-	return VM_FAULT_OOM;
-
-unwritable_page:
-	page_cache_release(old_page);
-	return VM_FAULT_SIGBUS;
-}
-
-/*
- * Helper functions for unmap_mapping_range().
- *
- * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
- *
- * We have to restart searching the prio_tree whenever we drop the lock,
- * since the iterator is only valid while the lock is held, and anyway
- * a later vma might be split and reinserted earlier while lock dropped.
- *
- * The list of nonlinear vmas could be handled more efficiently, using
- * a placeholder, but handle it in the same way until a need is shown.
- * It is important to search the prio_tree before nonlinear list: a vma
- * may become nonlinear and be shifted from prio_tree to nonlinear list
- * while the lock is dropped; but never shifted from list to prio_tree.
- *
- * In order to make forward progress despite restarting the search,
- * vm_truncate_count is used to mark a vma as now dealt with, so we can
- * quickly skip it next time around.  Since the prio_tree search only
- * shows us those vmas affected by unmapping the range in question, we
- * can't efficiently keep all vmas in step with mapping->truncate_count:
- * so instead reset them all whenever it wraps back to 0 (then go to 1).
- * mapping->truncate_count and vma->vm_truncate_count are protected by
- * i_mmap_lock.
- *
- * In order to make forward progress despite repeatedly restarting some
- * large vma, note the restart_addr from unmap_vmas when it breaks out:
- * and restart from that address when we reach that vma again.  It might
- * have been split or merged, shrunk or extended, but never shifted: so
- * restart_addr remains valid so long as it remains in the vma's range.
- * unmap_mapping_range forces truncate_count to leap over page-aligned
- * values so we can save vma's restart_addr in its truncate_count field.
- */
-#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
-
-static void reset_vma_truncate_counts(struct address_space *mapping)
-{
-	struct vm_area_struct *vma;
-	struct prio_tree_iter iter;
-
-	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
-		vma->vm_truncate_count = 0;
-	list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
-		vma->vm_truncate_count = 0;
-}
-
-static int unmap_mapping_range_vma(struct vm_area_struct *vma,
-		unsigned long start_addr, unsigned long end_addr,
-		struct zap_details *details)
-{
-	unsigned long restart_addr;
-	int need_break;
-
-	/*
-	 * files that support invalidating or truncating portions of the
-	 * file from under mmaped areas must have their ->fault function
-	 * return a locked page (and set VM_FAULT_LOCKED in the return).
-	 * This provides synchronisation against concurrent unmapping here.
-	 */
-
-again:
-	restart_addr = vma->vm_truncate_count;
-	if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
-		start_addr = restart_addr;
-		if (start_addr >= end_addr) {
-			/* Top of vma has been split off since last time */
-			vma->vm_truncate_count = details->truncate_count;
-			return 0;
-		}
-	}
-
-	restart_addr = zap_page_range(vma, start_addr,
-					end_addr - start_addr, details);
-	need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
-
-	if (restart_addr >= end_addr) {
-		/* We have now completed this vma: mark it so */
-		vma->vm_truncate_count = details->truncate_count;
-		if (!need_break)
-			return 0;
-	} else {
-		/* Note restart_addr in vma's truncate_count field */
-		vma->vm_truncate_count = restart_addr;
-		if (!need_break)
-			goto again;
-	}
-
-	spin_unlock(details->i_mmap_lock);
-	cond_resched();
-	spin_lock(details->i_mmap_lock);
-	return -EINTR;
-}
-
-static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
-					    struct zap_details *details)
-{
-	struct vm_area_struct *vma;
-	struct prio_tree_iter iter;
-	pgoff_t vba, vea, zba, zea;
-
-restart:
-	vma_prio_tree_foreach(vma, &iter, root,
-			details->first_index, details->last_index) {
-		/* Skip quickly over those we have already dealt with */
-		if (vma->vm_truncate_count == details->truncate_count)
-			continue;
-
-		vba = vma->vm_pgoff;
-		vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
-		/* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
-		zba = details->first_index;
-		if (zba < vba)
-			zba = vba;
-		zea = details->last_index;
-		if (zea > vea)
-			zea = vea;
-
-		if (unmap_mapping_range_vma(vma,
-			((zba - vba) << PAGE_SHIFT) + vma->vm_start,
-			((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
-				details) < 0)
-			goto restart;
-	}
-}
-
-static inline void unmap_mapping_range_list(struct list_head *head,
-					    struct zap_details *details)
-{
-	struct vm_area_struct *vma;
-
-	/*
-	 * In nonlinear VMAs there is no correspondence between virtual address
-	 * offset and file offset.  So we must perform an exhaustive search
-	 * across *all* the pages in each nonlinear VMA, not just the pages
-	 * whose virtual address lies outside the file truncation point.
-	 */
-restart:
-	list_for_each_entry(vma, head, shared.vm_set.list) {
-		/* Skip quickly over those we have already dealt with */
-		if (vma->vm_truncate_count == details->truncate_count)
-			continue;
-		details->nonlinear_vma = vma;
-		if (unmap_mapping_range_vma(vma, vma->vm_start,
-					vma->vm_end, details) < 0)
-			goto restart;
-	}
-}
-
-/**
- * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
- * @mapping: the address space containing mmaps to be unmapped.
- * @holebegin: byte in first page to unmap, relative to the start of
- * the underlying file.  This will be rounded down to a PAGE_SIZE
- * boundary.  Note that this is different from vmtruncate(), which
- * must keep the partial page.  In contrast, we must get rid of
- * partial pages.
- * @holelen: size of prospective hole in bytes.  This will be rounded
- * up to a PAGE_SIZE boundary.  A holelen of zero truncates to the
- * end of the file.
- * @even_cows: 1 when truncating a file, unmap even private COWed pages;
- * but 0 when invalidating pagecache, don't throw away private data.
- */
-void unmap_mapping_range(struct address_space *mapping,
-		loff_t const holebegin, loff_t const holelen, int even_cows)
-{
-	struct zap_details details;
-	pgoff_t hba = holebegin >> PAGE_SHIFT;
-	pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
-
-	/* Check for overflow. */
-	if (sizeof(holelen) > sizeof(hlen)) {
-		long long holeend =
-			(holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
-		if (holeend & ~(long long)ULONG_MAX)
-			hlen = ULONG_MAX - hba + 1;
-	}
-
-	details.check_mapping = even_cows? NULL: mapping;
-	details.nonlinear_vma = NULL;
-	details.first_index = hba;
-	details.last_index = hba + hlen - 1;
-	if (details.last_index < details.first_index)
-		details.last_index = ULONG_MAX;
-	details.i_mmap_lock = &mapping->i_mmap_lock;
-
-	spin_lock(&mapping->i_mmap_lock);
-
-	/* Protect against endless unmapping loops */
-	mapping->truncate_count++;
-	if (unlikely(is_restart_addr(mapping->truncate_count))) {
-		if (mapping->truncate_count == 0)
-			reset_vma_truncate_counts(mapping);
-		mapping->truncate_count++;
-	}
-	details.truncate_count = mapping->truncate_count;
-
-	if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
-		unmap_mapping_range_tree(&mapping->i_mmap, &details);
-	if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
-		unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
-	spin_unlock(&mapping->i_mmap_lock);
-}
-EXPORT_SYMBOL(unmap_mapping_range);
-
-/**
- * vmtruncate - unmap mappings "freed" by truncate() syscall
- * @inode: inode of the file used
- * @offset: file offset to start truncating
- *
- * NOTE! We have to be ready to update the memory sharing
- * between the file and the memory map for a potential last
- * incomplete page.  Ugly, but necessary.
- */
-int vmtruncate(struct inode * inode, loff_t offset)
-{
-	if (inode->i_size < offset) {
-		unsigned long limit;
-
-		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-		if (limit != RLIM_INFINITY && offset > limit)
-			goto out_sig;
-		if (offset > inode->i_sb->s_maxbytes)
-			goto out_big;
-		i_size_write(inode, offset);
-	} else {
-		struct address_space *mapping = inode->i_mapping;
-
-		/*
-		 * truncation of in-use swapfiles is disallowed - it would
-		 * cause subsequent swapout to scribble on the now-freed
-		 * blocks.
-		 */
-		if (IS_SWAPFILE(inode))
-			return -ETXTBSY;
-		i_size_write(inode, offset);
-
-		/*
-		 * unmap_mapping_range is called twice, first simply for
-		 * efficiency so that truncate_inode_pages does fewer
-		 * single-page unmaps.  However after this first call, and
-		 * before truncate_inode_pages finishes, it is possible for
-		 * private pages to be COWed, which remain after
-		 * truncate_inode_pages finishes, hence the second
-		 * unmap_mapping_range call must be made for correctness.
-		 */
-		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-		truncate_inode_pages(mapping, offset);
-		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-	}
-
-	if (inode->i_op->truncate)
-		inode->i_op->truncate(inode);
-	return 0;
-
-out_sig:
-	send_sig(SIGXFSZ, current, 0);
-out_big:
-	return -EFBIG;
-}
-EXPORT_SYMBOL(vmtruncate);
-
-int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
-{
-	struct address_space *mapping = inode->i_mapping;
-
-	/*
-	 * If the underlying filesystem is not going to provide
-	 * a way to truncate a range of blocks (punch a hole) -
-	 * we should return failure right now.
-	 */
-	if (!inode->i_op->truncate_range)
-		return -ENOSYS;
-
-	mutex_lock(&inode->i_mutex);
-	down_write(&inode->i_alloc_sem);
-	unmap_mapping_range(mapping, offset, (end - offset), 1);
-	truncate_inode_pages_range(mapping, offset, end);
-	unmap_mapping_range(mapping, offset, (end - offset), 1);
-	inode->i_op->truncate_range(inode, offset, end);
-	up_write(&inode->i_alloc_sem);
-	mutex_unlock(&inode->i_mutex);
-
-	return 0;
-}
-
-/*
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- */
-static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		int write_access, pte_t orig_pte)
-{
-	spinlock_t *ptl;
-	struct page *page;
-	swp_entry_t entry;
-	pte_t pte;
-	struct mem_cgroup *ptr = NULL;
-	int ret = 0;
-
-	if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
-		goto out;
-
-	entry = pte_to_swp_entry(orig_pte);
-	if (is_migration_entry(entry)) {
-		migration_entry_wait(mm, pmd, address);
-		goto out;
-	}
-	delayacct_set_flag(DELAYACCT_PF_SWAPIN);
-	page = lookup_swap_cache(entry);
-	if (!page) {
-		grab_swap_token(); /* Contend for token _before_ read-in */
-		page = swapin_readahead(entry,
-					GFP_HIGHUSER_MOVABLE, vma, address);
-		if (!page) {
-			/*
-			 * Back out if somebody else faulted in this pte
-			 * while we released the pte lock.
-			 */
-			page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-			if (likely(pte_same(*page_table, orig_pte)))
-				ret = VM_FAULT_OOM;
-			delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
-			goto unlock;
-		}
-
-		/* Had to read the page from swap area: Major fault */
-		ret = VM_FAULT_MAJOR;
-		count_vm_event(PGMAJFAULT);
-	}
-
-	mark_page_accessed(page);
-
-	lock_page(page);
-	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
-
-	if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
-		ret = VM_FAULT_OOM;
-		unlock_page(page);
-		goto out;
-	}
-
-	/*
-	 * Back out if somebody else already faulted in this pte.
-	 */
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (unlikely(!pte_same(*page_table, orig_pte)))
-		goto out_nomap;
-
-	if (unlikely(!PageUptodate(page))) {
-		ret = VM_FAULT_SIGBUS;
-		goto out_nomap;
-	}
-
-	/*
-	 * The page isn't present yet, go ahead with the fault.
-	 *
-	 * Be careful about the sequence of operations here.
-	 * To get its accounting right, reuse_swap_page() must be called
-	 * while the page is counted on swap but not yet in mapcount i.e.
-	 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
-	 * must be called after the swap_free(), or it will never succeed.
-	 * Because delete_from_swap_page() may be called by reuse_swap_page(),
-	 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
-	 * in page->private. In this case, a record in swap_cgroup  is silently
-	 * discarded at swap_free().
-	 */
-
-	inc_mm_counter(mm, anon_rss);
-	pte = mk_pte(page, vma->vm_page_prot);
-	if (write_access && reuse_swap_page(page)) {
-		pte = maybe_mkwrite(pte_mkdirty(pte), vma);
-		write_access = 0;
-	}
-	flush_icache_page(vma, page);
-	set_pte_at(mm, address, page_table, pte);
-	page_add_anon_rmap(page, vma, address);
-	/* It's better to call commit-charge after rmap is established */
-	mem_cgroup_commit_charge_swapin(page, ptr);
-
-	swap_free(entry);
-	if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
-		try_to_free_swap(page);
-	unlock_page(page);
-
-	if (write_access) {
-		ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
-		if (ret & VM_FAULT_ERROR)
-			ret &= VM_FAULT_ERROR;
-		goto out;
-	}
-
-	/* No need to invalidate - it was non-present before */
-	update_mmu_cache(vma, address, pte);
-unlock:
-	pte_unmap_unlock(page_table, ptl);
-out:
-	return ret;
-out_nomap:
-	mem_cgroup_cancel_charge_swapin(ptr);
-	pte_unmap_unlock(page_table, ptl);
-	unlock_page(page);
-	page_cache_release(page);
-	return ret;
-}
-
-/*
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- */
-static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		int write_access)
-{
-	struct page *page;
-	spinlock_t *ptl;
-	pte_t entry;
-
-	/* Allocate our own private page. */
-	pte_unmap(page_table);
-
-	if (unlikely(anon_vma_prepare(vma)))
-		goto oom;
-	page = alloc_zeroed_user_highpage_movable(vma, address);
-	if (!page)
-		goto oom;
-	__SetPageUptodate(page);
-
-	if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
-		goto oom_free_page;
-
-	entry = mk_pte(page, vma->vm_page_prot);
-	entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (!pte_none(*page_table))
-		goto release;
-	inc_mm_counter(mm, anon_rss);
-	page_add_new_anon_rmap(page, vma, address);
-	set_pte_at(mm, address, page_table, entry);
-
-	/* No need to invalidate - it was non-present before */
-	update_mmu_cache(vma, address, entry);
-unlock:
-	pte_unmap_unlock(page_table, ptl);
-	return 0;
-release:
-	mem_cgroup_uncharge_page(page);
-	page_cache_release(page);
-	goto unlock;
-oom_free_page:
-	page_cache_release(page);
-oom:
-	return VM_FAULT_OOM;
-}
-
-/*
- * __do_fault() tries to create a new page mapping. It aggressively
- * tries to share with existing pages, but makes a separate copy if
- * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
- * the next page fault.
- *
- * As this is called only for pages that do not currently exist, we
- * do not need to flush old virtual caches or the TLB.
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte neither mapped nor locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- */
-static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pmd_t *pmd,
-		pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
-{
-	pte_t *page_table;
-	spinlock_t *ptl;
-	struct page *page;
-	pte_t entry;
-	int anon = 0;
-	int charged = 0;
-	struct page *dirty_page = NULL;
-	struct vm_fault vmf;
-	int ret;
-	int page_mkwrite = 0;
-
-	vmf.virtual_address = (void __user *)(address & PAGE_MASK);
-	vmf.pgoff = pgoff;
-	vmf.flags = flags;
-	vmf.page = NULL;
-
-	ret = vma->vm_ops->fault(vma, &vmf);
-	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
-		return ret;
-
-	/*
-	 * For consistency in subsequent calls, make the faulted page always
-	 * locked.
-	 */
-	if (unlikely(!(ret & VM_FAULT_LOCKED)))
-		lock_page(vmf.page);
-	else
-		VM_BUG_ON(!PageLocked(vmf.page));
-
-	/*
-	 * Should we do an early C-O-W break?
-	 */
-	page = vmf.page;
-	if (flags & FAULT_FLAG_WRITE) {
-		if (!(vma->vm_flags & VM_SHARED)) {
-			anon = 1;
-			if (unlikely(anon_vma_prepare(vma))) {
-				ret = VM_FAULT_OOM;
-				goto out;
-			}
-			page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
-						vma, address);
-			if (!page) {
-				ret = VM_FAULT_OOM;
-				goto out;
-			}
-			if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
-				ret = VM_FAULT_OOM;
-				page_cache_release(page);
-				goto out;
-			}
-			charged = 1;
-			/*
-			 * Don't let another task, with possibly unlocked vma,
-			 * keep the mlocked page.
-			 */
-			if (vma->vm_flags & VM_LOCKED)
-				clear_page_mlock(vmf.page);
-			copy_user_highpage(page, vmf.page, address, vma);
-			__SetPageUptodate(page);
-		} else {
-			/*
-			 * If the page will be shareable, see if the backing
-			 * address space wants to know that the page is about
-			 * to become writable
-			 */
-			if (vma->vm_ops->page_mkwrite) {
-				unlock_page(page);
-				if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
-					ret = VM_FAULT_SIGBUS;
-					anon = 1; /* no anon but release vmf.page */
-					goto out_unlocked;
-				}
-				lock_page(page);
-				/*
-				 * XXX: this is not quite right (racy vs
-				 * invalidate) to unlock and relock the page
-				 * like this, however a better fix requires
-				 * reworking page_mkwrite locking API, which
-				 * is better done later.
-				 */
-				if (!page->mapping) {
-					ret = 0;
-					anon = 1; /* no anon but release vmf.page */
-					goto out;
-				}
-				page_mkwrite = 1;
-			}
-		}
-
-	}
-
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-
-	/*
-	 * This silly early PAGE_DIRTY setting removes a race
-	 * due to the bad i386 page protection. But it's valid
-	 * for other architectures too.
-	 *
-	 * Note that if write_access is true, we either now have
-	 * an exclusive copy of the page, or this is a shared mapping,
-	 * so we can make it writable and dirty to avoid having to
-	 * handle that later.
-	 */
-	/* Only go through if we didn't race with anybody else... */
-	if (likely(pte_same(*page_table, orig_pte))) {
-		flush_icache_page(vma, page);
-		entry = mk_pte(page, vma->vm_page_prot);
-		if (flags & FAULT_FLAG_WRITE)
-			entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-		if (anon) {
-			inc_mm_counter(mm, anon_rss);
-			page_add_new_anon_rmap(page, vma, address);
-		} else {
-			inc_mm_counter(mm, file_rss);
-			page_add_file_rmap(page);
-			if (flags & FAULT_FLAG_WRITE) {
-				dirty_page = page;
-				get_page(dirty_page);
-			}
-		}
-		set_pte_at(mm, address, page_table, entry);
-
-		/* no need to invalidate: a not-present page won't be cached */
-		update_mmu_cache(vma, address, entry);
-	} else {
-		if (charged)
-			mem_cgroup_uncharge_page(page);
-		if (anon)
-			page_cache_release(page);
-		else
-			anon = 1; /* no anon but release faulted_page */
-	}
-
-	pte_unmap_unlock(page_table, ptl);
-
-out:
-	unlock_page(vmf.page);
-out_unlocked:
-	if (anon)
-		page_cache_release(vmf.page);
-	else if (dirty_page) {
-		if (vma->vm_file)
-			file_update_time(vma->vm_file);
-
-		set_page_dirty_balance(dirty_page, page_mkwrite);
-		put_page(dirty_page);
-	}
-
-	return ret;
-}
-
-static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		int write_access, pte_t orig_pte)
-{
-	pgoff_t pgoff = (((address & PAGE_MASK)
-			- vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
-	unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
-
-	pte_unmap(page_table);
-	return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
-}
-
-/*
- * Fault of a previously existing named mapping. Repopulate the pte
- * from the encoded file_pte if possible. This enables swappable
- * nonlinear vmas.
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- */
-static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		int write_access, pte_t orig_pte)
-{
-	unsigned int flags = FAULT_FLAG_NONLINEAR |
-				(write_access ? FAULT_FLAG_WRITE : 0);
-	pgoff_t pgoff;
-
-	if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
-		return 0;
-
-	if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
-		/*
-		 * Page table corrupted: show pte and kill process.
-		 */
-		print_bad_pte(vma, address, orig_pte, NULL);
-		return VM_FAULT_OOM;
-	}
-
-	pgoff = pte_to_pgoff(orig_pte);
-	return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
-}
-
-/*
- * These routines also need to handle stuff like marking pages dirty
- * and/or accessed for architectures that don't do it in hardware (most
- * RISC architectures).  The early dirtying is also good on the i386.
- *
- * There is also a hook called "update_mmu_cache()" that architectures
- * with external mmu caches can use to update those (ie the Sparc or
- * PowerPC hashed page tables that act as extended TLBs).
- *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with mmap_sem still held, but pte unmapped and unlocked.
- */
-static inline int handle_pte_fault(struct mm_struct *mm,
-		struct vm_area_struct *vma, unsigned long address,
-		pte_t *pte, pmd_t *pmd, int write_access)
-{
-	pte_t entry;
-	spinlock_t *ptl;
-
-	entry = *pte;
-	if (!pte_present(entry)) {
-		if (pte_none(entry)) {
-			if (vma->vm_ops) {
-				if (likely(vma->vm_ops->fault))
-					return do_linear_fault(mm, vma, address,
-						pte, pmd, write_access, entry);
-			}
-			return do_anonymous_page(mm, vma, address,
-						 pte, pmd, write_access);
-		}
-		if (pte_file(entry))
-			return do_nonlinear_fault(mm, vma, address,
-					pte, pmd, write_access, entry);
-		return do_swap_page(mm, vma, address,
-					pte, pmd, write_access, entry);
-	}
-
-	ptl = pte_lockptr(mm, pmd);
-	spin_lock(ptl);
-	if (unlikely(!pte_same(*pte, entry)))
-		goto unlock;
-	if (write_access) {
-		if (!pte_write(entry))
-			return do_wp_page(mm, vma, address,
-					pte, pmd, ptl, entry);
-		entry = pte_mkdirty(entry);
-	}
-	entry = pte_mkyoung(entry);
-	if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
-		update_mmu_cache(vma, address, entry);
-	} else {
-		/*
-		 * This is needed only for protection faults but the arch code
-		 * is not yet telling us if this is a protection fault or not.
-		 * This still avoids useless tlb flushes for .text page faults
-		 * with threads.
-		 */
-		if (write_access)
-			flush_tlb_page(vma, address);
-	}
-unlock:
-	pte_unmap_unlock(pte, ptl);
-	return 0;
-}
-
-/*
- * By the time we get here, we already hold the mm semaphore
- */
-int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, int write_access)
-{
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-
-	__set_current_state(TASK_RUNNING);
-
-	count_vm_event(PGFAULT);
-
-	if (unlikely(is_vm_hugetlb_page(vma)))
-		return hugetlb_fault(mm, vma, address, write_access);
-
-	pgd = pgd_offset(mm, address);
-	pud = pud_alloc(mm, pgd, address);
-	if (!pud)
-		return VM_FAULT_OOM;
-	pmd = pmd_alloc(mm, pud, address);
-	if (!pmd)
-		return VM_FAULT_OOM;
-	pte = pte_alloc_map(mm, pmd, address);
-	if (!pte)
-		return VM_FAULT_OOM;
-
-	return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
-}
-
-#ifndef __PAGETABLE_PUD_FOLDED
-/*
- * Allocate page upper directory.
- * We've already handled the fast-path in-line.
- */
-int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
-{
-	pud_t *new = pud_alloc_one(mm, address);
-	if (!new)
-		return -ENOMEM;
-
-	smp_wmb(); /* See comment in __pte_alloc */
-
-	spin_lock(&mm->page_table_lock);
-	if (pgd_present(*pgd))		/* Another has populated it */
-		pud_free(mm, new);
-	else
-		pgd_populate(mm, pgd, new);
-	spin_unlock(&mm->page_table_lock);
-	return 0;
-}
-#endif /* __PAGETABLE_PUD_FOLDED */
-
-#ifndef __PAGETABLE_PMD_FOLDED
-/*
- * Allocate page middle directory.
- * We've already handled the fast-path in-line.
- */
-int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
-{
-	pmd_t *new = pmd_alloc_one(mm, address);
-	if (!new)
-		return -ENOMEM;
-
-	smp_wmb(); /* See comment in __pte_alloc */
-
-	spin_lock(&mm->page_table_lock);
-#ifndef __ARCH_HAS_4LEVEL_HACK
-	if (pud_present(*pud))		/* Another has populated it */
-		pmd_free(mm, new);
-	else
-		pud_populate(mm, pud, new);
-#else
-	if (pgd_present(*pud))		/* Another has populated it */
-		pmd_free(mm, new);
-	else
-		pgd_populate(mm, pud, new);
-#endif /* __ARCH_HAS_4LEVEL_HACK */
-	spin_unlock(&mm->page_table_lock);
-	return 0;
-}
-#endif /* __PAGETABLE_PMD_FOLDED */
-
-int make_pages_present(unsigned long addr, unsigned long end)
-{
-	int ret, len, write;
-	struct vm_area_struct * vma;
-
-	vma = find_vma(current->mm, addr);
-	if (!vma)
-		return -ENOMEM;
-	write = (vma->vm_flags & VM_WRITE) != 0;
-	BUG_ON(addr >= end);
-	BUG_ON(end > vma->vm_end);
-	len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
-	ret = get_user_pages(current, current->mm, addr,
-			len, write, 0, NULL, NULL);
-	if (ret < 0)
-		return ret;
-	return ret == len ? 0 : -EFAULT;
-}
-
-#if !defined(__HAVE_ARCH_GATE_AREA)
-
-#if defined(AT_SYSINFO_EHDR)
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	gate_vma.vm_mm = NULL;
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
-	gate_vma.vm_page_prot = __P101;
-	/*
-	 * Make sure the vDSO gets into every core dump.
-	 * Dumping its contents makes post-mortem fully interpretable later
-	 * without matching up the same kernel and hardware config to see
-	 * what PC values meant.
-	 */
-	gate_vma.vm_flags |= VM_ALWAYSDUMP;
-	return 0;
-}
-__initcall(gate_vma_init);
-#endif
-
-struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
-{
-#ifdef AT_SYSINFO_EHDR
-	return &gate_vma;
-#else
-	return NULL;
-#endif
-}
-
-int in_gate_area_no_task(unsigned long addr)
-{
-#ifdef AT_SYSINFO_EHDR
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-#endif
-	return 0;
-}
-
-#endif	/* __HAVE_ARCH_GATE_AREA */
-
-#ifdef CONFIG_HAVE_IOREMAP_PROT
-int follow_phys(struct vm_area_struct *vma,
-		unsigned long address, unsigned int flags,
-		unsigned long *prot, resource_size_t *phys)
-{
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *ptep, pte;
-	spinlock_t *ptl;
-	resource_size_t phys_addr = 0;
-	struct mm_struct *mm = vma->vm_mm;
-	int ret = -EINVAL;
-
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		goto out;
-
-	pgd = pgd_offset(mm, address);
-	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
-		goto out;
-
-	pud = pud_offset(pgd, address);
-	if (pud_none(*pud) || unlikely(pud_bad(*pud)))
-		goto out;
-
-	pmd = pmd_offset(pud, address);
-	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
-		goto out;
-
-	/* We cannot handle huge page PFN maps. Luckily they don't exist. */
-	if (pmd_huge(*pmd))
-		goto out;
-
-	ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (!ptep)
-		goto out;
-
-	pte = *ptep;
-	if (!pte_present(pte))
-		goto unlock;
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
-		goto unlock;
-	phys_addr = pte_pfn(pte);
-	phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */
-
-	*prot = pgprot_val(pte_pgprot(pte));
-	*phys = phys_addr;
-	ret = 0;
-
-unlock:
-	pte_unmap_unlock(ptep, ptl);
-out:
-	return ret;
-}
-
-int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
-			void *buf, int len, int write)
-{
-	resource_size_t phys_addr;
-	unsigned long prot = 0;
-	void __iomem *maddr;
-	int offset = addr & (PAGE_SIZE-1);
-
-	if (follow_phys(vma, addr, write, &prot, &phys_addr))
-		return -EINVAL;
-
-	maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
-	if (write)
-		memcpy_toio(maddr + offset, buf, len);
-	else
-		memcpy_fromio(buf, maddr + offset, len);
-	iounmap(maddr);
-
-	return len;
-}
-#endif
-
-/*
- * Access another process' address space.
- * Source/target buffer must be kernel space,
- * Do not walk the page table directly, use get_user_pages
- */
-int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
-{
-	struct mm_struct *mm;
-	struct vm_area_struct *vma;
-	void *old_buf = buf;
-
-	mm = get_task_mm(tsk);
-	if (!mm)
-		return 0;
-
-	down_read(&mm->mmap_sem);
-	/* ignore errors, just check how much was successfully transferred */
-	while (len) {
-		int bytes, ret, offset;
-		void *maddr;
-		struct page *page = NULL;
-
-		ret = get_user_pages(tsk, mm, addr, 1,
-				write, 1, &page, &vma);
-		if (ret <= 0) {
-			/*
-			 * Check if this is a VM_IO | VM_PFNMAP VMA, which
-			 * we can access using slightly different code.
-			 */
-#ifdef CONFIG_HAVE_IOREMAP_PROT
-			vma = find_vma(mm, addr);
-			if (!vma)
-				break;
-			if (vma->vm_ops && vma->vm_ops->access)
-				ret = vma->vm_ops->access(vma, addr, buf,
-							  len, write);
-			if (ret <= 0)
-#endif
-				break;
-			bytes = ret;
-		} else {
-			bytes = len;
-			offset = addr & (PAGE_SIZE-1);
-			if (bytes > PAGE_SIZE-offset)
-				bytes = PAGE_SIZE-offset;
-
-			maddr = kmap(page);
-			if (write) {
-				copy_to_user_page(vma, page, addr,
-						  maddr + offset, buf, bytes);
-				set_page_dirty_lock(page);
-			} else {
-				copy_from_user_page(vma, page, addr,
-						    buf, maddr + offset, bytes);
-			}
-			kunmap(page);
-			page_cache_release(page);
-		}
-		len -= bytes;
-		buf += bytes;
-		addr += bytes;
-	}
-	up_read(&mm->mmap_sem);
-	mmput(mm);
-
-	return buf - old_buf;
-}
-
-/*
- * Print the name of a VMA.
- */
-void print_vma_addr(char *prefix, unsigned long ip)
-{
-	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
-
-	/*
-	 * Do not print if we are in atomic
-	 * contexts (in exception stacks, etc.):
-	 */
-	if (preempt_count())
-		return;
-
-	down_read(&mm->mmap_sem);
-	vma = find_vma(mm, ip);
-	if (vma && vma->vm_file) {
-		struct file *f = vma->vm_file;
-		char *buf = (char *)__get_free_page(GFP_KERNEL);
-		if (buf) {
-			char *p, *s;
-
-			p = d_path(&f->f_path, buf, PAGE_SIZE);
-			if (IS_ERR(p))
-				p = "?";
-			s = strrchr(p, '/');
-			if (s)
-				p = s+1;
-			printk("%s%s[%lx+%lx]", prefix, p,
-					vma->vm_start,
-					vma->vm_end - vma->vm_start);
-			free_page((unsigned long)buf);
-		}
-	}
-	up_read(&current->mm->mmap_sem);
-}
-
-#ifdef CONFIG_PROVE_LOCKING
-void might_fault(void)
-{
-	/*
-	 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
-	 * holding the mmap_sem, this is safe because kernel memory doesn't
-	 * get paged out, therefore we'll never actually fault, and the
-	 * below annotations will generate false positives.
-	 */
-	if (segment_eq(get_fs(), KERNEL_DS))
-		return;
-
-	might_sleep();
-	/*
-	 * it would be nicer only to annotate paths which are not under
-	 * pagefault_disable, however that requires a larger audit and
-	 * providing helpers like get_user_atomic.
-	 */
-	if (!in_atomic() && current->mm)
-		might_lock_read(&current->mm->mmap_sem);
-}
-EXPORT_SYMBOL(might_fault);
-#endif
-#endif /* DDE_LINUX */
diff --git a/libdde_linux26/lib/src/mm/page-writeback.c b/libdde_linux26/lib/src/mm/page-writeback.c
deleted file mode 100644
index 8a325e2a..00000000
--- a/libdde_linux26/lib/src/mm/page-writeback.c
+++ /dev/null
@@ -1,1468 +0,0 @@
-/*
- * mm/page-writeback.c
- *
- * Copyright (C) 2002, Linus Torvalds.
- * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
- *
- * Contains functions related to writing back dirty pages at the
- * address_space level.
- *
- * 10Apr2002	Andrew Morton
- *		Initial version
- */
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/swap.h>
-#include <linux/slab.h>
-#include <linux/pagemap.h>
-#include <linux/writeback.h>
-#include <linux/init.h>
-#include <linux/backing-dev.h>
-#include <linux/task_io_accounting_ops.h>
-#include <linux/blkdev.h>
-#include <linux/mpage.h>
-#include <linux/rmap.h>
-#include <linux/percpu.h>
-#include <linux/notifier.h>
-#include <linux/smp.h>
-#include <linux/sysctl.h>
-#include <linux/cpu.h>
-#include <linux/syscalls.h>
-#include <linux/buffer_head.h>
-#include <linux/pagevec.h>
-
-/*
- * The maximum number of pages to writeout in a single bdflush/kupdate
- * operation.  We do this so we don't hold I_SYNC against an inode for
- * enormous amounts of time, which would block a userspace task which has
- * been forced to throttle against that inode.  Also, the code reevaluates
- * the dirty each time it has written this many pages.
- */
-#define MAX_WRITEBACK_PAGES	1024
-
-/*
- * After a CPU has dirtied this many pages, balance_dirty_pages_ratelimited
- * will look to see if it needs to force writeback or throttling.
- */
-static long ratelimit_pages = 32;
-
-/*
- * When balance_dirty_pages decides that the caller needs to perform some
- * non-background writeback, this is how many pages it will attempt to write.
- * It should be somewhat larger than RATELIMIT_PAGES to ensure that reasonably
- * large amounts of I/O are submitted.
- */
-static inline long sync_writeback_pages(void)
-{
-	return ratelimit_pages + ratelimit_pages / 2;
-}
-
-/* The following parameters are exported via /proc/sys/vm */
-
-/*
- * Start background writeback (via pdflush) at this percentage
- */
-int dirty_background_ratio = 5;
-
-/*
- * dirty_background_bytes starts at 0 (disabled) so that it is a function of
- * dirty_background_ratio * the amount of dirtyable memory
- */
-unsigned long dirty_background_bytes;
-
-/*
- * free highmem will not be subtracted from the total free memory
- * for calculating free ratios if vm_highmem_is_dirtyable is true
- */
-int vm_highmem_is_dirtyable;
-
-/*
- * The generator of dirty data starts writeback at this percentage
- */
-int vm_dirty_ratio = 10;
-
-/*
- * vm_dirty_bytes starts at 0 (disabled) so that it is a function of
- * vm_dirty_ratio * the amount of dirtyable memory
- */
-unsigned long vm_dirty_bytes;
-
-/*
- * The interval between `kupdate'-style writebacks, in jiffies
- */
-#ifndef DDE_LINUX
-int dirty_writeback_interval = 5 * HZ;
-#else
-int dirty_writeback_interval = 1250;
-#endif
-
-#ifndef DDE_LINUX
-/*
- * The longest number of jiffies for which data is allowed to remain dirty
- */
-int dirty_expire_interval = 30 * HZ;
-#else
-int dirty_expire_interval = 7500;
-#endif
-
-/*
- * Flag that makes the machine dump writes/reads and block dirtyings.
- */
-int block_dump;
-
-/*
- * Flag that puts the machine in "laptop mode". Doubles as a timeout in jiffies:
- * a full sync is triggered after this time elapses without any disk activity.
- */
-int laptop_mode;
-
-EXPORT_SYMBOL(laptop_mode);
-
-/* End of sysctl-exported parameters */
-
-
-static void background_writeout(unsigned long _min_pages);
-
-/*
- * Scale the writeback cache size proportional to the relative writeout speeds.
- *
- * We do this by keeping a floating proportion between BDIs, based on page
- * writeback completions [end_page_writeback()]. Those devices that write out
- * pages fastest will get the larger share, while the slower will get a smaller
- * share.
- *
- * We use page writeout completions because we are interested in getting rid of
- * dirty pages. Having them written out is the primary goal.
- *
- * We introduce a concept of time, a period over which we measure these events,
- * because demand can/will vary over time. The length of this period itself is
- * measured in page writeback completions.
- *
- */
-static struct prop_descriptor vm_completions;
-static struct prop_descriptor vm_dirties;
-
-/*
- * couple the period to the dirty_ratio:
- *
- *   period/2 ~ roundup_pow_of_two(dirty limit)
- */
-static int calc_period_shift(void)
-{
-	unsigned long dirty_total;
-
-	if (vm_dirty_bytes)
-		dirty_total = vm_dirty_bytes / PAGE_SIZE;
-	else
-		dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) /
-				100;
-	return 2 + ilog2(dirty_total - 1);
-}
-
-/*
- * update the period when the dirty threshold changes.
- */
-static void update_completion_period(void)
-{
-	int shift = calc_period_shift();
-	prop_change_shift(&vm_completions, shift);
-	prop_change_shift(&vm_dirties, shift);
-}
-
-int dirty_background_ratio_handler(struct ctl_table *table, int write,
-		struct file *filp, void __user *buffer, size_t *lenp,
-		loff_t *ppos)
-{
-	int ret;
-
-	ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
-	if (ret == 0 && write)
-		dirty_background_bytes = 0;
-	return ret;
-}
-
-int dirty_background_bytes_handler(struct ctl_table *table, int write,
-		struct file *filp, void __user *buffer, size_t *lenp,
-		loff_t *ppos)
-{
-	int ret;
-
-	ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
-	if (ret == 0 && write)
-		dirty_background_ratio = 0;
-	return ret;
-}
-
-int dirty_ratio_handler(struct ctl_table *table, int write,
-		struct file *filp, void __user *buffer, size_t *lenp,
-		loff_t *ppos)
-{
-	int old_ratio = vm_dirty_ratio;
-	int ret;
-
-	ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
-	if (ret == 0 && write && vm_dirty_ratio != old_ratio) {
-		update_completion_period();
-		vm_dirty_bytes = 0;
-	}
-	return ret;
-}
-
-
-int dirty_bytes_handler(struct ctl_table *table, int write,
-		struct file *filp, void __user *buffer, size_t *lenp,
-		loff_t *ppos)
-{
-	unsigned long old_bytes = vm_dirty_bytes;
-	int ret;
-
-	ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
-	if (ret == 0 && write && vm_dirty_bytes != old_bytes) {
-		update_completion_period();
-		vm_dirty_ratio = 0;
-	}
-	return ret;
-}
-
-/*
- * Increment the BDI's writeout completion count and the global writeout
- * completion count. Called from test_clear_page_writeback().
- */
-static inline void __bdi_writeout_inc(struct backing_dev_info *bdi)
-{
-	__prop_inc_percpu_max(&vm_completions, &bdi->completions,
-			      bdi->max_prop_frac);
-}
-
-void bdi_writeout_inc(struct backing_dev_info *bdi)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	__bdi_writeout_inc(bdi);
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(bdi_writeout_inc);
-
-void task_dirty_inc(struct task_struct *tsk)
-{
-	prop_inc_single(&vm_dirties, &tsk->dirties);
-}
-
-/*
- * Obtain an accurate fraction of the BDI's portion.
- */
-static void bdi_writeout_fraction(struct backing_dev_info *bdi,
-		long *numerator, long *denominator)
-{
-	if (bdi_cap_writeback_dirty(bdi)) {
-		prop_fraction_percpu(&vm_completions, &bdi->completions,
-				numerator, denominator);
-	} else {
-		*numerator = 0;
-		*denominator = 1;
-	}
-}
-
-/*
- * Clip the earned share of dirty pages to that which is actually available.
- * This avoids exceeding the total dirty_limit when the floating averages
- * fluctuate too quickly.
- */
-static void
-clip_bdi_dirty_limit(struct backing_dev_info *bdi, long dirty, long *pbdi_dirty)
-{
-	long avail_dirty;
-
-	avail_dirty = dirty -
-		(global_page_state(NR_FILE_DIRTY) +
-		 global_page_state(NR_WRITEBACK) +
-		 global_page_state(NR_UNSTABLE_NFS) +
-		 global_page_state(NR_WRITEBACK_TEMP));
-
-	if (avail_dirty < 0)
-		avail_dirty = 0;
-
-	avail_dirty += bdi_stat(bdi, BDI_RECLAIMABLE) +
-		bdi_stat(bdi, BDI_WRITEBACK);
-
-	*pbdi_dirty = min(*pbdi_dirty, avail_dirty);
-}
-
-static inline void task_dirties_fraction(struct task_struct *tsk,
-		long *numerator, long *denominator)
-{
-	prop_fraction_single(&vm_dirties, &tsk->dirties,
-				numerator, denominator);
-}
-
-/*
- * scale the dirty limit
- *
- * task specific dirty limit:
- *
- *   dirty -= (dirty/8) * p_{t}
- */
-static void task_dirty_limit(struct task_struct *tsk, long *pdirty)
-{
-	long numerator, denominator;
-	long dirty = *pdirty;
-	u64 inv = dirty >> 3;
-
-	task_dirties_fraction(tsk, &numerator, &denominator);
-	inv *= numerator;
-	do_div(inv, denominator);
-
-	dirty -= inv;
-	if (dirty < *pdirty/2)
-		dirty = *pdirty/2;
-
-	*pdirty = dirty;
-}
-
-/*
- *
- */
-static DEFINE_SPINLOCK(bdi_lock);
-static unsigned int bdi_min_ratio;
-
-int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
-{
-	int ret = 0;
-	unsigned long flags;
-
-	spin_lock_irqsave(&bdi_lock, flags);
-	if (min_ratio > bdi->max_ratio) {
-		ret = -EINVAL;
-	} else {
-		min_ratio -= bdi->min_ratio;
-		if (bdi_min_ratio + min_ratio < 100) {
-			bdi_min_ratio += min_ratio;
-			bdi->min_ratio += min_ratio;
-		} else {
-			ret = -EINVAL;
-		}
-	}
-	spin_unlock_irqrestore(&bdi_lock, flags);
-
-	return ret;
-}
-
-int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio)
-{
-	unsigned long flags;
-	int ret = 0;
-
-	if (max_ratio > 100)
-		return -EINVAL;
-
-	spin_lock_irqsave(&bdi_lock, flags);
-	if (bdi->min_ratio > max_ratio) {
-		ret = -EINVAL;
-	} else {
-		bdi->max_ratio = max_ratio;
-		bdi->max_prop_frac = (PROP_FRAC_BASE * max_ratio) / 100;
-	}
-	spin_unlock_irqrestore(&bdi_lock, flags);
-
-	return ret;
-}
-EXPORT_SYMBOL(bdi_set_max_ratio);
-
-/*
- * Work out the current dirty-memory clamping and background writeout
- * thresholds.
- *
- * The main aim here is to lower them aggressively if there is a lot of mapped
- * memory around.  To avoid stressing page reclaim with lots of unreclaimable
- * pages.  It is better to clamp down on writers than to start swapping, and
- * performing lots of scanning.
- *
- * We only allow 1/2 of the currently-unmapped memory to be dirtied.
- *
- * We don't permit the clamping level to fall below 5% - that is getting rather
- * excessive.
- *
- * We make sure that the background writeout level is below the adjusted
- * clamping level.
- */
-
-static unsigned long highmem_dirtyable_memory(unsigned long total)
-{
-#ifdef CONFIG_HIGHMEM
-	int node;
-	unsigned long x = 0;
-
-	for_each_node_state(node, N_HIGH_MEMORY) {
-		struct zone *z =
-			&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
-
-		x += zone_page_state(z, NR_FREE_PAGES) + zone_lru_pages(z);
-	}
-	/*
-	 * Make sure that the number of highmem pages is never larger
-	 * than the number of the total dirtyable memory. This can only
-	 * occur in very strange VM situations but we want to make sure
-	 * that this does not occur.
-	 */
-	return min(x, total);
-#else
-	return 0;
-#endif
-}
-
-/**
- * determine_dirtyable_memory - amount of memory that may be used
- *
- * Returns the numebr of pages that can currently be freed and used
- * by the kernel for direct mappings.
- */
-unsigned long determine_dirtyable_memory(void)
-{
-	unsigned long x;
-
-	x = global_page_state(NR_FREE_PAGES) + global_lru_pages();
-
-	if (!vm_highmem_is_dirtyable)
-		x -= highmem_dirtyable_memory(x);
-
-	return x + 1;	/* Ensure that we never return 0 */
-}
-
-void
-get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
-		 unsigned long *pbdi_dirty, struct backing_dev_info *bdi)
-{
-	unsigned long background;
-	unsigned long dirty;
-	unsigned long available_memory = determine_dirtyable_memory();
-	struct task_struct *tsk;
-
-	if (vm_dirty_bytes)
-		dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
-	else {
-		int dirty_ratio;
-
-		dirty_ratio = vm_dirty_ratio;
-		if (dirty_ratio < 5)
-			dirty_ratio = 5;
-		dirty = (dirty_ratio * available_memory) / 100;
-	}
-
-	if (dirty_background_bytes)
-		background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
-	else
-		background = (dirty_background_ratio * available_memory) / 100;
-
-	if (background >= dirty)
-		background = dirty / 2;
-	tsk = current;
-	if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) {
-		background += background / 4;
-		dirty += dirty / 4;
-	}
-	*pbackground = background;
-	*pdirty = dirty;
-
-	if (bdi) {
-		u64 bdi_dirty;
-		long numerator, denominator;
-
-		/*
-		 * Calculate this BDI's share of the dirty ratio.
-		 */
-		bdi_writeout_fraction(bdi, &numerator, &denominator);
-
-		bdi_dirty = (dirty * (100 - bdi_min_ratio)) / 100;
-		bdi_dirty *= numerator;
-		do_div(bdi_dirty, denominator);
-		bdi_dirty += (dirty * bdi->min_ratio) / 100;
-		if (bdi_dirty > (dirty * bdi->max_ratio) / 100)
-			bdi_dirty = dirty * bdi->max_ratio / 100;
-
-		*pbdi_dirty = bdi_dirty;
-		clip_bdi_dirty_limit(bdi, dirty, pbdi_dirty);
-		task_dirty_limit(current, pbdi_dirty);
-	}
-}
-
-/*
- * balance_dirty_pages() must be called by processes which are generating dirty
- * data.  It looks at the number of dirty pages in the machine and will force
- * the caller to perform writeback if the system is over `vm_dirty_ratio'.
- * If we're over `background_thresh' then pdflush is woken to perform some
- * writeout.
- */
-static void balance_dirty_pages(struct address_space *mapping)
-{
-	long nr_reclaimable, bdi_nr_reclaimable;
-	long nr_writeback, bdi_nr_writeback;
-	unsigned long background_thresh;
-	unsigned long dirty_thresh;
-	unsigned long bdi_thresh;
-	unsigned long pages_written = 0;
-	unsigned long write_chunk = sync_writeback_pages();
-
-	struct backing_dev_info *bdi = mapping->backing_dev_info;
-
-	for (;;) {
-		struct writeback_control wbc = {
-			.bdi		= bdi,
-			.sync_mode	= WB_SYNC_NONE,
-			.older_than_this = NULL,
-			.nr_to_write	= write_chunk,
-			.range_cyclic	= 1,
-		};
-
-		get_dirty_limits(&background_thresh, &dirty_thresh,
-				&bdi_thresh, bdi);
-
-		nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
-					global_page_state(NR_UNSTABLE_NFS);
-		nr_writeback = global_page_state(NR_WRITEBACK);
-
-		bdi_nr_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE);
-		bdi_nr_writeback = bdi_stat(bdi, BDI_WRITEBACK);
-
-		if (bdi_nr_reclaimable + bdi_nr_writeback <= bdi_thresh)
-			break;
-
-		/*
-		 * Throttle it only when the background writeback cannot
-		 * catch-up. This avoids (excessively) small writeouts
-		 * when the bdi limits are ramping up.
-		 */
-		if (nr_reclaimable + nr_writeback <
-				(background_thresh + dirty_thresh) / 2)
-			break;
-
-		if (!bdi->dirty_exceeded)
-			bdi->dirty_exceeded = 1;
-
-		/* Note: nr_reclaimable denotes nr_dirty + nr_unstable.
-		 * Unstable writes are a feature of certain networked
-		 * filesystems (i.e. NFS) in which data may have been
-		 * written to the server's write cache, but has not yet
-		 * been flushed to permanent storage.
-		 */
-		if (bdi_nr_reclaimable) {
-			writeback_inodes(&wbc);
-			pages_written += write_chunk - wbc.nr_to_write;
-			get_dirty_limits(&background_thresh, &dirty_thresh,
-				       &bdi_thresh, bdi);
-		}
-
-		/*
-		 * In order to avoid the stacked BDI deadlock we need
-		 * to ensure we accurately count the 'dirty' pages when
-		 * the threshold is low.
-		 *
-		 * Otherwise it would be possible to get thresh+n pages
-		 * reported dirty, even though there are thresh-m pages
-		 * actually dirty; with m+n sitting in the percpu
-		 * deltas.
-		 */
-		if (bdi_thresh < 2*bdi_stat_error(bdi)) {
-			bdi_nr_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE);
-			bdi_nr_writeback = bdi_stat_sum(bdi, BDI_WRITEBACK);
-		} else if (bdi_nr_reclaimable) {
-			bdi_nr_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE);
-			bdi_nr_writeback = bdi_stat(bdi, BDI_WRITEBACK);
-		}
-
-		if (bdi_nr_reclaimable + bdi_nr_writeback <= bdi_thresh)
-			break;
-		if (pages_written >= write_chunk)
-			break;		/* We've done our duty */
-
-		congestion_wait(WRITE, HZ/10);
-	}
-
-	if (bdi_nr_reclaimable + bdi_nr_writeback < bdi_thresh &&
-			bdi->dirty_exceeded)
-		bdi->dirty_exceeded = 0;
-
-	if (writeback_in_progress(bdi))
-		return;		/* pdflush is already working this queue */
-
-	/*
-	 * In laptop mode, we wait until hitting the higher threshold before
-	 * starting background writeout, and then write out all the way down
-	 * to the lower threshold.  So slow writers cause minimal disk activity.
-	 *
-	 * In normal mode, we start background writeout at the lower
-	 * background_thresh, to keep the amount of dirty memory low.
-	 */
-	if ((laptop_mode && pages_written) ||
-			(!laptop_mode && (global_page_state(NR_FILE_DIRTY)
-					  + global_page_state(NR_UNSTABLE_NFS)
-					  > background_thresh)))
-		pdflush_operation(background_writeout, 0);
-}
-
-void set_page_dirty_balance(struct page *page, int page_mkwrite)
-{
-	if (set_page_dirty(page) || page_mkwrite) {
-		struct address_space *mapping = page_mapping(page);
-
-		if (mapping)
-			balance_dirty_pages_ratelimited(mapping);
-	}
-}
-
-/**
- * balance_dirty_pages_ratelimited_nr - balance dirty memory state
- * @mapping: address_space which was dirtied
- * @nr_pages_dirtied: number of pages which the caller has just dirtied
- *
- * Processes which are dirtying memory should call in here once for each page
- * which was newly dirtied.  The function will periodically check the system's
- * dirty state and will initiate writeback if needed.
- *
- * On really big machines, get_writeback_state is expensive, so try to avoid
- * calling it too often (ratelimiting).  But once we're over the dirty memory
- * limit we decrease the ratelimiting by a lot, to prevent individual processes
- * from overshooting the limit by (ratelimit_pages) each.
- */
-void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
-					unsigned long nr_pages_dirtied)
-{
-	static DEFINE_PER_CPU(unsigned long, ratelimits) = 0;
-	unsigned long ratelimit;
-	unsigned long *p;
-
-	ratelimit = ratelimit_pages;
-	if (mapping->backing_dev_info->dirty_exceeded)
-		ratelimit = 8;
-
-	/*
-	 * Check the rate limiting. Also, we do not want to throttle real-time
-	 * tasks in balance_dirty_pages(). Period.
-	 */
-	preempt_disable();
-	p =  &__get_cpu_var(ratelimits);
-	*p += nr_pages_dirtied;
-	if (unlikely(*p >= ratelimit)) {
-		*p = 0;
-		preempt_enable();
-		balance_dirty_pages(mapping);
-		return;
-	}
-	preempt_enable();
-}
-EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);
-
-void throttle_vm_writeout(gfp_t gfp_mask)
-{
-	unsigned long background_thresh;
-	unsigned long dirty_thresh;
-
-        for ( ; ; ) {
-		get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
-
-                /*
-                 * Boost the allowable dirty threshold a bit for page
-                 * allocators so they don't get DoS'ed by heavy writers
-                 */
-                dirty_thresh += dirty_thresh / 10;      /* wheeee... */
-
-                if (global_page_state(NR_UNSTABLE_NFS) +
-			global_page_state(NR_WRITEBACK) <= dirty_thresh)
-                        	break;
-                congestion_wait(WRITE, HZ/10);
-
-		/*
-		 * The caller might hold locks which can prevent IO completion
-		 * or progress in the filesystem.  So we cannot just sit here
-		 * waiting for IO to complete.
-		 */
-		if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO))
-			break;
-        }
-}
-
-/*
- * writeback at least _min_pages, and keep writing until the amount of dirty
- * memory is less than the background threshold, or until we're all clean.
- */
-static void background_writeout(unsigned long _min_pages)
-{
-	long min_pages = _min_pages;
-	struct writeback_control wbc = {
-		.bdi		= NULL,
-		.sync_mode	= WB_SYNC_NONE,
-		.older_than_this = NULL,
-		.nr_to_write	= 0,
-		.nonblocking	= 1,
-		.range_cyclic	= 1,
-	};
-
-	for ( ; ; ) {
-		unsigned long background_thresh;
-		unsigned long dirty_thresh;
-
-		get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
-		if (global_page_state(NR_FILE_DIRTY) +
-			global_page_state(NR_UNSTABLE_NFS) < background_thresh
-				&& min_pages <= 0)
-			break;
-		wbc.more_io = 0;
-		wbc.encountered_congestion = 0;
-		wbc.nr_to_write = MAX_WRITEBACK_PAGES;
-		wbc.pages_skipped = 0;
-		writeback_inodes(&wbc);
-		min_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
-		if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) {
-			/* Wrote less than expected */
-			if (wbc.encountered_congestion || wbc.more_io)
-				congestion_wait(WRITE, HZ/10);
-			else
-				break;
-		}
-	}
-}
-
-/*
- * Start writeback of `nr_pages' pages.  If `nr_pages' is zero, write back
- * the whole world.  Returns 0 if a pdflush thread was dispatched.  Returns
- * -1 if all pdflush threads were busy.
- */
-int wakeup_pdflush(long nr_pages)
-{
-	if (nr_pages == 0)
-		nr_pages = global_page_state(NR_FILE_DIRTY) +
-				global_page_state(NR_UNSTABLE_NFS);
-	return pdflush_operation(background_writeout, nr_pages);
-}
-
-#ifndef DDE_LINUX
-static void wb_timer_fn(unsigned long unused);
-static void laptop_timer_fn(unsigned long unused);
-
-static DEFINE_TIMER(wb_timer, wb_timer_fn, 0, 0);
-static DEFINE_TIMER(laptop_mode_wb_timer, laptop_timer_fn, 0, 0);
-
-/*
- * Periodic writeback of "old" data.
- *
- * Define "old": the first time one of an inode's pages is dirtied, we mark the
- * dirtying-time in the inode's address_space.  So this periodic writeback code
- * just walks the superblock inode list, writing back any inodes which are
- * older than a specific point in time.
- *
- * Try to run once per dirty_writeback_interval.  But if a writeback event
- * takes longer than a dirty_writeback_interval interval, then leave a
- * one-second gap.
- *
- * older_than_this takes precedence over nr_to_write.  So we'll only write back
- * all dirty pages if they are all attached to "old" mappings.
- */
-static void wb_kupdate(unsigned long arg)
-{
-	unsigned long oldest_jif;
-	unsigned long start_jif;
-	unsigned long next_jif;
-	long nr_to_write;
-	struct writeback_control wbc = {
-		.bdi		= NULL,
-		.sync_mode	= WB_SYNC_NONE,
-		.older_than_this = &oldest_jif,
-		.nr_to_write	= 0,
-		.nonblocking	= 1,
-		.for_kupdate	= 1,
-		.range_cyclic	= 1,
-	};
-
-	sync_supers();
-
-	oldest_jif = jiffies - dirty_expire_interval;
-	start_jif = jiffies;
-	next_jif = start_jif + dirty_writeback_interval;
-	nr_to_write = global_page_state(NR_FILE_DIRTY) +
-			global_page_state(NR_UNSTABLE_NFS) +
-			(inodes_stat.nr_inodes - inodes_stat.nr_unused);
-	while (nr_to_write > 0) {
-		wbc.more_io = 0;
-		wbc.encountered_congestion = 0;
-		wbc.nr_to_write = MAX_WRITEBACK_PAGES;
-		writeback_inodes(&wbc);
-		if (wbc.nr_to_write > 0) {
-			if (wbc.encountered_congestion || wbc.more_io)
-				congestion_wait(WRITE, HZ/10);
-			else
-				break;	/* All the old data is written */
-		}
-		nr_to_write -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
-	}
-	if (time_before(next_jif, jiffies + HZ))
-		next_jif = jiffies + HZ;
-	if (dirty_writeback_interval)
-		mod_timer(&wb_timer, next_jif);
-}
-
-/*
- * sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
- */
-int dirty_writeback_centisecs_handler(ctl_table *table, int write,
-	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
-{
-	proc_dointvec_userhz_jiffies(table, write, file, buffer, length, ppos);
-	if (dirty_writeback_interval)
-		mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
-	else
-		del_timer(&wb_timer);
-	return 0;
-}
-
-static void wb_timer_fn(unsigned long unused)
-{
-	if (pdflush_operation(wb_kupdate, 0) < 0)
-		mod_timer(&wb_timer, jiffies + HZ); /* delay 1 second */
-}
-
-static void laptop_flush(unsigned long unused)
-{
-	sys_sync();
-}
-
-static void laptop_timer_fn(unsigned long unused)
-{
-	pdflush_operation(laptop_flush, 0);
-}
-
-/*
- * We've spun up the disk and we're in laptop mode: schedule writeback
- * of all dirty data a few seconds from now.  If the flush is already scheduled
- * then push it back - the user is still using the disk.
- */
-void laptop_io_completion(void)
-{
-	mod_timer(&laptop_mode_wb_timer, jiffies + laptop_mode);
-}
-
-/*
- * We're in laptop mode and we've just synced. The sync's writes will have
- * caused another writeback to be scheduled by laptop_io_completion.
- * Nothing needs to be written back anymore, so we unschedule the writeback.
- */
-void laptop_sync_completion(void)
-{
-	del_timer(&laptop_mode_wb_timer);
-}
-#endif
-
-/*
- * If ratelimit_pages is too high then we can get into dirty-data overload
- * if a large number of processes all perform writes at the same time.
- * If it is too low then SMP machines will call the (expensive)
- * get_writeback_state too often.
- *
- * Here we set ratelimit_pages to a level which ensures that when all CPUs are
- * dirtying in parallel, we cannot go more than 3% (1/32) over the dirty memory
- * thresholds before writeback cuts in.
- *
- * But the limit should not be set too high.  Because it also controls the
- * amount of memory which the balance_dirty_pages() caller has to write back.
- * If this is too large then the caller will block on the IO queue all the
- * time.  So limit it to four megabytes - the balance_dirty_pages() caller
- * will write six megabyte chunks, max.
- */
-
-void writeback_set_ratelimit(void)
-{
-	ratelimit_pages = vm_total_pages / (num_online_cpus() * 32);
-	if (ratelimit_pages < 16)
-		ratelimit_pages = 16;
-	if (ratelimit_pages * PAGE_CACHE_SIZE > 4096 * 1024)
-		ratelimit_pages = (4096 * 1024) / PAGE_CACHE_SIZE;
-}
-
-static int __cpuinit
-ratelimit_handler(struct notifier_block *self, unsigned long u, void *v)
-{
-	writeback_set_ratelimit();
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block __cpuinitdata ratelimit_nb = {
-	.notifier_call	= ratelimit_handler,
-	.next		= NULL,
-};
-
-/*
- * Called early on to tune the page writeback dirty limits.
- *
- * We used to scale dirty pages according to how total memory
- * related to pages that could be allocated for buffers (by
- * comparing nr_free_buffer_pages() to vm_total_pages.
- *
- * However, that was when we used "dirty_ratio" to scale with
- * all memory, and we don't do that any more. "dirty_ratio"
- * is now applied to total non-HIGHPAGE memory (by subtracting
- * totalhigh_pages from vm_total_pages), and as such we can't
- * get into the old insane situation any more where we had
- * large amounts of dirty pages compared to a small amount of
- * non-HIGHMEM memory.
- *
- * But we might still want to scale the dirty_ratio by how
- * much memory the box has..
- */
-void __init page_writeback_init(void)
-{
-	int shift;
-
-#ifndef DDE_LINUX
-	mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
-#endif
-	writeback_set_ratelimit();
-	register_cpu_notifier(&ratelimit_nb);
-
-	shift = calc_period_shift();
-	prop_descriptor_init(&vm_completions, shift);
-	prop_descriptor_init(&vm_dirties, shift);
-}
-
-/**
- * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
- * @mapping: address space structure to write
- * @wbc: subtract the number of written pages from *@wbc->nr_to_write
- * @writepage: function called for each page
- * @data: data passed to writepage function
- *
- * If a page is already under I/O, write_cache_pages() skips it, even
- * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
- * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
- * and msync() need to guarantee that all the data which was dirty at the time
- * the call was made get new I/O started against them.  If wbc->sync_mode is
- * WB_SYNC_ALL then we were called for data integrity and we must wait for
- * existing IO to complete.
- */
-int write_cache_pages(struct address_space *mapping,
-		      struct writeback_control *wbc, writepage_t writepage,
-		      void *data)
-{
-	struct backing_dev_info *bdi = mapping->backing_dev_info;
-	int ret = 0;
-	int done = 0;
-	struct pagevec pvec;
-	int nr_pages;
-	pgoff_t uninitialized_var(writeback_index);
-	pgoff_t index;
-	pgoff_t end;		/* Inclusive */
-	pgoff_t done_index;
-	int cycled;
-	int range_whole = 0;
-	long nr_to_write = wbc->nr_to_write;
-
-	if (wbc->nonblocking && bdi_write_congested(bdi)) {
-		wbc->encountered_congestion = 1;
-		return 0;
-	}
-
-	pagevec_init(&pvec, 0);
-	if (wbc->range_cyclic) {
-		writeback_index = mapping->writeback_index; /* prev offset */
-		index = writeback_index;
-		if (index == 0)
-			cycled = 1;
-		else
-			cycled = 0;
-		end = -1;
-	} else {
-		index = wbc->range_start >> PAGE_CACHE_SHIFT;
-		end = wbc->range_end >> PAGE_CACHE_SHIFT;
-		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
-			range_whole = 1;
-		cycled = 1; /* ignore range_cyclic tests */
-	}
-retry:
-	done_index = index;
-	while (!done && (index <= end)) {
-		int i;
-
-		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
-			      PAGECACHE_TAG_DIRTY,
-			      min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
-		if (nr_pages == 0)
-			break;
-
-		for (i = 0; i < nr_pages; i++) {
-			struct page *page = pvec.pages[i];
-
-			/*
-			 * At this point, the page may be truncated or
-			 * invalidated (changing page->mapping to NULL), or
-			 * even swizzled back from swapper_space to tmpfs file
-			 * mapping. However, page->index will not change
-			 * because we have a reference on the page.
-			 */
-			if (page->index > end) {
-				/*
-				 * can't be range_cyclic (1st pass) because
-				 * end == -1 in that case.
-				 */
-				done = 1;
-				break;
-			}
-
-			done_index = page->index + 1;
-
-			lock_page(page);
-
-			/*
-			 * Page truncated or invalidated. We can freely skip it
-			 * then, even for data integrity operations: the page
-			 * has disappeared concurrently, so there could be no
-			 * real expectation of this data interity operation
-			 * even if there is now a new, dirty page at the same
-			 * pagecache address.
-			 */
-			if (unlikely(page->mapping != mapping)) {
-continue_unlock:
-				unlock_page(page);
-				continue;
-			}
-
-			if (!PageDirty(page)) {
-				/* someone wrote it for us */
-				goto continue_unlock;
-			}
-
-			if (PageWriteback(page)) {
-				if (wbc->sync_mode != WB_SYNC_NONE)
-					wait_on_page_writeback(page);
-				else
-					goto continue_unlock;
-			}
-
-			BUG_ON(PageWriteback(page));
-			if (!clear_page_dirty_for_io(page))
-				goto continue_unlock;
-
-			ret = (*writepage)(page, wbc, data);
-			if (unlikely(ret)) {
-				if (ret == AOP_WRITEPAGE_ACTIVATE) {
-					unlock_page(page);
-					ret = 0;
-				} else {
-					/*
-					 * done_index is set past this page,
-					 * so media errors will not choke
-					 * background writeout for the entire
-					 * file. This has consequences for
-					 * range_cyclic semantics (ie. it may
-					 * not be suitable for data integrity
-					 * writeout).
-					 */
-					done = 1;
-					break;
-				}
- 			}
-
-			if (nr_to_write > 0) {
-				nr_to_write--;
-				if (nr_to_write == 0 &&
-				    wbc->sync_mode == WB_SYNC_NONE) {
-					/*
-					 * We stop writing back only if we are
-					 * not doing integrity sync. In case of
-					 * integrity sync we have to keep going
-					 * because someone may be concurrently
-					 * dirtying pages, and we might have
-					 * synced a lot of newly appeared dirty
-					 * pages, but have not synced all of the
-					 * old dirty pages.
-					 */
-					done = 1;
-					break;
-				}
-			}
-
-			if (wbc->nonblocking && bdi_write_congested(bdi)) {
-				wbc->encountered_congestion = 1;
-				done = 1;
-				break;
-			}
-		}
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-	if (!cycled && !done) {
-		/*
-		 * range_cyclic:
-		 * We hit the last page and there is more work to be done: wrap
-		 * back to the start of the file
-		 */
-		cycled = 1;
-		index = 0;
-		end = writeback_index - 1;
-		goto retry;
-	}
-	if (!wbc->no_nrwrite_index_update) {
-		if (wbc->range_cyclic || (range_whole && nr_to_write > 0))
-			mapping->writeback_index = done_index;
-		wbc->nr_to_write = nr_to_write;
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL(write_cache_pages);
-
-#ifndef DDE_LINUX
-/*
- * Function used by generic_writepages to call the real writepage
- * function and set the mapping flags on error
- */
-static int __writepage(struct page *page, struct writeback_control *wbc,
-		       void *data)
-{
-	struct address_space *mapping = data;
-	int ret = mapping->a_ops->writepage(page, wbc);
-	mapping_set_error(mapping, ret);
-	return ret;
-}
-
-/**
- * generic_writepages - walk the list of dirty pages of the given address space and writepage() all of them.
- * @mapping: address space structure to write
- * @wbc: subtract the number of written pages from *@wbc->nr_to_write
- *
- * This is a library function, which implements the writepages()
- * address_space_operation.
- */
-int generic_writepages(struct address_space *mapping,
-		       struct writeback_control *wbc)
-{
-	/* deal with chardevs and other special file */
-	if (!mapping->a_ops->writepage)
-		return 0;
-
-	return write_cache_pages(mapping, wbc, __writepage, mapping);
-}
-
-EXPORT_SYMBOL(generic_writepages);
-
-int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
-{
-	int ret;
-
-	if (wbc->nr_to_write <= 0)
-		return 0;
-	wbc->for_writepages = 1;
-	if (mapping->a_ops->writepages)
-		ret = mapping->a_ops->writepages(mapping, wbc);
-	else
-		ret = generic_writepages(mapping, wbc);
-	wbc->for_writepages = 0;
-	return ret;
-}
-
-/**
- * write_one_page - write out a single page and optionally wait on I/O
- * @page: the page to write
- * @wait: if true, wait on writeout
- *
- * The page must be locked by the caller and will be unlocked upon return.
- *
- * write_one_page() returns a negative error code if I/O failed.
- */
-int write_one_page(struct page *page, int wait)
-{
-	struct address_space *mapping = page->mapping;
-	int ret = 0;
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_ALL,
-		.nr_to_write = 1,
-	};
-
-	BUG_ON(!PageLocked(page));
-
-	if (wait)
-		wait_on_page_writeback(page);
-
-	if (clear_page_dirty_for_io(page)) {
-		page_cache_get(page);
-		ret = mapping->a_ops->writepage(page, &wbc);
-		if (ret == 0 && wait) {
-			wait_on_page_writeback(page);
-			if (PageError(page))
-				ret = -EIO;
-		}
-		page_cache_release(page);
-	} else {
-		unlock_page(page);
-	}
-	return ret;
-}
-EXPORT_SYMBOL(write_one_page);
-
-/*
- * For address_spaces which do not use buffers nor write back.
- */
-int __set_page_dirty_no_writeback(struct page *page)
-{
-	if (!PageDirty(page))
-		SetPageDirty(page);
-	return 0;
-}
-
-/*
- * For address_spaces which do not use buffers.  Just tag the page as dirty in
- * its radix tree.
- *
- * This is also used when a single buffer is being dirtied: we want to set the
- * page dirty in that case, but not all the buffers.  This is a "bottom-up"
- * dirtying, whereas __set_page_dirty_buffers() is a "top-down" dirtying.
- *
- * Most callers have locked the page, which pins the address_space in memory.
- * But zap_pte_range() does not lock the page, however in that case the
- * mapping is pinned by the vma's ->vm_file reference.
- *
- * We take care to handle the case where the page was truncated from the
- * mapping by re-checking page_mapping() inside tree_lock.
- */
-int __set_page_dirty_nobuffers(struct page *page)
-{
-	if (!TestSetPageDirty(page)) {
-		struct address_space *mapping = page_mapping(page);
-		struct address_space *mapping2;
-
-		if (!mapping)
-			return 1;
-
-		spin_lock_irq(&mapping->tree_lock);
-		mapping2 = page_mapping(page);
-		if (mapping2) { /* Race with truncate? */
-			BUG_ON(mapping2 != mapping);
-			WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
-			if (mapping_cap_account_dirty(mapping)) {
-				__inc_zone_page_state(page, NR_FILE_DIRTY);
-				__inc_bdi_stat(mapping->backing_dev_info,
-						BDI_RECLAIMABLE);
-				task_dirty_inc(current);
-				task_io_account_write(PAGE_CACHE_SIZE);
-			}
-			radix_tree_tag_set(&mapping->page_tree,
-				page_index(page), PAGECACHE_TAG_DIRTY);
-		}
-		spin_unlock_irq(&mapping->tree_lock);
-		if (mapping->host) {
-			/* !PageAnon && !swapper_space */
-			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
-		}
-		return 1;
-	}
-	return 0;
-}
-EXPORT_SYMBOL(__set_page_dirty_nobuffers);
-
-/*
- * When a writepage implementation decides that it doesn't want to write this
- * page for some reason, it should redirty the locked page via
- * redirty_page_for_writepage() and it should then unlock the page and return 0
- */
-int redirty_page_for_writepage(struct writeback_control *wbc, struct page *page)
-{
-	wbc->pages_skipped++;
-	return __set_page_dirty_nobuffers(page);
-}
-EXPORT_SYMBOL(redirty_page_for_writepage);
-
-/*
- * If the mapping doesn't provide a set_page_dirty a_op, then
- * just fall through and assume that it wants buffer_heads.
- */
-int set_page_dirty(struct page *page)
-{
-	struct address_space *mapping = page_mapping(page);
-
-	if (likely(mapping)) {
-		int (*spd)(struct page *) = mapping->a_ops->set_page_dirty;
-#ifdef CONFIG_BLOCK
-		if (!spd)
-			spd = __set_page_dirty_buffers;
-#endif
-		return (*spd)(page);
-	}
-	if (!PageDirty(page)) {
-		if (!TestSetPageDirty(page))
-			return 1;
-	}
-	return 0;
-}
-EXPORT_SYMBOL(set_page_dirty);
-
-/*
- * set_page_dirty() is racy if the caller has no reference against
- * page->mapping->host, and if the page is unlocked.  This is because another
- * CPU could truncate the page off the mapping and then free the mapping.
- *
- * Usually, the page _is_ locked, or the caller is a user-space process which
- * holds a reference on the inode by having an open file.
- *
- * In other cases, the page should be locked before running set_page_dirty().
- */
-int set_page_dirty_lock(struct page *page)
-{
-	int ret;
-
-	lock_page_nosync(page);
-	ret = set_page_dirty(page);
-	unlock_page(page);
-	return ret;
-}
-EXPORT_SYMBOL(set_page_dirty_lock);
-#endif
-
-/*
- * Clear a page's dirty flag, while caring for dirty memory accounting.
- * Returns true if the page was previously dirty.
- *
- * This is for preparing to put the page under writeout.  We leave the page
- * tagged as dirty in the radix tree so that a concurrent write-for-sync
- * can discover it via a PAGECACHE_TAG_DIRTY walk.  The ->writepage
- * implementation will run either set_page_writeback() or set_page_dirty(),
- * at which stage we bring the page's dirty flag and radix-tree dirty tag
- * back into sync.
- *
- * This incoherency between the page's dirty flag and radix-tree tag is
- * unfortunate, but it only exists while the page is locked.
- */
-int clear_page_dirty_for_io(struct page *page)
-{
-	struct address_space *mapping = page_mapping(page);
-
-	BUG_ON(!PageLocked(page));
-
-	ClearPageReclaim(page);
-	if (mapping && mapping_cap_account_dirty(mapping)) {
-		/*
-		 * Yes, Virginia, this is indeed insane.
-		 *
-		 * We use this sequence to make sure that
-		 *  (a) we account for dirty stats properly
-		 *  (b) we tell the low-level filesystem to
-		 *      mark the whole page dirty if it was
-		 *      dirty in a pagetable. Only to then
-		 *  (c) clean the page again and return 1 to
-		 *      cause the writeback.
-		 *
-		 * This way we avoid all nasty races with the
-		 * dirty bit in multiple places and clearing
-		 * them concurrently from different threads.
-		 *
-		 * Note! Normally the "set_page_dirty(page)"
-		 * has no effect on the actual dirty bit - since
-		 * that will already usually be set. But we
-		 * need the side effects, and it can help us
-		 * avoid races.
-		 *
-		 * We basically use the page "master dirty bit"
-		 * as a serialization point for all the different
-		 * threads doing their things.
-		 */
-		if (page_mkclean(page))
-			set_page_dirty(page);
-		/*
-		 * We carefully synchronise fault handlers against
-		 * installing a dirty pte and marking the page dirty
-		 * at this point. We do this by having them hold the
-		 * page lock at some point after installing their
-		 * pte, but before marking the page dirty.
-		 * Pages are always locked coming in here, so we get
-		 * the desired exclusion. See mm/memory.c:do_wp_page()
-		 * for more comments.
-		 */
-		if (TestClearPageDirty(page)) {
-			dec_zone_page_state(page, NR_FILE_DIRTY);
-			dec_bdi_stat(mapping->backing_dev_info,
-					BDI_RECLAIMABLE);
-			return 1;
-		}
-		return 0;
-	}
-	return TestClearPageDirty(page);
-}
-EXPORT_SYMBOL(clear_page_dirty_for_io);
-
-int test_clear_page_writeback(struct page *page)
-{
-	struct address_space *mapping = page_mapping(page);
-	int ret;
-
-	if (mapping) {
-		struct backing_dev_info *bdi = mapping->backing_dev_info;
-		unsigned long flags;
-
-		spin_lock_irqsave(&mapping->tree_lock, flags);
-		ret = TestClearPageWriteback(page);
-		if (ret) {
-			radix_tree_tag_clear(&mapping->page_tree,
-						page_index(page),
-						PAGECACHE_TAG_WRITEBACK);
-			if (bdi_cap_account_writeback(bdi)) {
-				__dec_bdi_stat(bdi, BDI_WRITEBACK);
-				__bdi_writeout_inc(bdi);
-			}
-		}
-		spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	} else {
-		ret = TestClearPageWriteback(page);
-	}
-	if (ret)
-		dec_zone_page_state(page, NR_WRITEBACK);
-	return ret;
-}
-
-#ifndef DDE_LINUX
-int test_set_page_writeback(struct page *page)
-{
-	struct address_space *mapping = page_mapping(page);
-	int ret;
-
-	if (mapping) {
-		struct backing_dev_info *bdi = mapping->backing_dev_info;
-		unsigned long flags;
-
-		spin_lock_irqsave(&mapping->tree_lock, flags);
-		ret = TestSetPageWriteback(page);
-		if (!ret) {
-			radix_tree_tag_set(&mapping->page_tree,
-						page_index(page),
-						PAGECACHE_TAG_WRITEBACK);
-			if (bdi_cap_account_writeback(bdi))
-				__inc_bdi_stat(bdi, BDI_WRITEBACK);
-		}
-		if (!PageDirty(page))
-			radix_tree_tag_clear(&mapping->page_tree,
-						page_index(page),
-						PAGECACHE_TAG_DIRTY);
-		spin_unlock_irqrestore(&mapping->tree_lock, flags);
-	} else {
-		ret = TestSetPageWriteback(page);
-	}
-	if (!ret)
-		inc_zone_page_state(page, NR_WRITEBACK);
-	return ret;
-
-}
-EXPORT_SYMBOL(test_set_page_writeback);
-#endif /* DDE_LINUX */
-
-/*
- * Return true if any of the pages in the mapping are marked with the
- * passed tag.
- */
-int mapping_tagged(struct address_space *mapping, int tag)
-{
-	int ret;
-	rcu_read_lock();
-	ret = radix_tree_tagged(&mapping->page_tree, tag);
-	rcu_read_unlock();
-	return ret;
-}
-EXPORT_SYMBOL(mapping_tagged);