diff options
Diffstat (limited to 'libpager')
| -rw-r--r-- | libpager/data-unlock.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/libpager/data-unlock.c b/libpager/data-unlock.c new file mode 100644 index 00000000..038a3339 --- /dev/null +++ b/libpager/data-unlock.c @@ -0,0 +1,98 @@ +/* Implementation of memory_object_data_unlock for pager library + Copyright (C) 1994 Free Software Foundation + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Called by the kernel to request a lock on memory. */ +/* We provide all data read-write except for "holes". Therefore, + lock requests should only happen for holes, and this routine does the + allocation. */ +kern_return_t +seqnos_memory_object_data_unlock (mach_port_t object, + mach_port_seqno_t seqno, + mach_port_t control, + vm_offset_t offset, + vm_size_t length, + vm_prot_t access) +{ + struct pager *p; + volatile int err; + struct inode *volatile ip; + daddr_t newblk; + daddr_t vblkno; + daddr_t *slot; + daddr_t *table; + + if (!(p = check_port_type (object, PT_PAGER))) + return EOPNOTSUPP; + + mutex_lock (&p->interlock); + wait_for_seqno (p, seqno); + release_seqno (p); + mutex_unlock (&p->interlock); + + if (p->pager_state != NORMAL) + { + printf ("pager in wrong state for unlock\n"); + goto out; + } + + if (control != p->memobjcntl) + { + printf ("incg data unlock: wrong control port"); + goto out; + } + /* The only thing we ever block is writes */ + if ((access & VM_PROT_WRITE) == 0) + { + printf ("incg data unlock: not unlock writes"); + goto out; + } + if (offset % __vm_page_size) + { + printf ("incg data unlock: misaligned request"); + goto out; + } + if (length != __vm_page_size) + { + printf ("incg data request: bad length size"); + goto out; + } + + if (shutting_down) + { + /* Let the kernel stew. */ + return EIEIO; + } + + err = pager_unlock_page (p->upi, offset); + + if (!err) + /* We can go ahead and release the lock. */ + lock_object (p, offset, length, MEMORY_OBJECT_RETURN_NONE, 0, + VM_PROT_NONE, 0); + else + { + /* Flush the page, and set a bit so that m_o_data_request knows + to issue an error. */ + lock_object (p, offset, length, MEMORY_OBJECT_RETURN_NONE, 1, + VM_PROT_WRITE, 1); + mark_next_request_error (p, offset, length, err); + } + out: + done_with_port (p); + return 0; +} + |