diff options
Diffstat (limited to 'libdde-linux26/libdde_linux26/contrib/block/elevator.c')
| -rw-r--r-- | libdde-linux26/libdde_linux26/contrib/block/elevator.c | 1231 |
1 files changed, 0 insertions, 1231 deletions
diff --git a/libdde-linux26/libdde_linux26/contrib/block/elevator.c b/libdde-linux26/libdde_linux26/contrib/block/elevator.c deleted file mode 100644 index 0287fafd..00000000 --- a/libdde-linux26/libdde_linux26/contrib/block/elevator.c +++ /dev/null @@ -1,1231 +0,0 @@ -/* - * Block device elevator/IO-scheduler. - * - * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE - * - * 30042000 Jens Axboe <axboe@kernel.dk> : - * - * Split the elevator a bit so that it is possible to choose a different - * one or even write a new "plug in". There are three pieces: - * - elevator_fn, inserts a new request in the queue list - * - elevator_merge_fn, decides whether a new buffer can be merged with - * an existing request - * - elevator_dequeue_fn, called when a request is taken off the active list - * - * 20082000 Dave Jones <davej@suse.de> : - * Removed tests for max-bomb-segments, which was breaking elvtune - * when run without -bN - * - * Jens: - * - Rework again to work with bio instead of buffer_heads - * - loose bi_dev comparisons, partition handling is right now - * - completely modularize elevator setup and teardown - * - */ -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/compiler.h> -#include <linux/delay.h> -#include <linux/blktrace_api.h> -#include <trace/block.h> -#include <linux/hash.h> -#include <linux/uaccess.h> - -#include "blk.h" -#include "local.h" - -static DEFINE_SPINLOCK(elv_list_lock); -static LIST_HEAD(elv_list); - -DEFINE_TRACE(block_rq_abort); - -/* - * Merge hash stuff. - */ -static const int elv_hash_shift = 6; -#define ELV_HASH_BLOCK(sec) ((sec) >> 3) -#define ELV_HASH_FN(sec) \ - (hash_long(ELV_HASH_BLOCK((sec)), elv_hash_shift)) -#define ELV_HASH_ENTRIES (1 << elv_hash_shift) -#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) -#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) - -DEFINE_TRACE(block_rq_insert); -DEFINE_TRACE(block_rq_issue); - -/* - * Query io scheduler to see if the current process issuing bio may be - * merged with rq. - */ -static int elv_iosched_allow_merge(struct request *rq, struct bio *bio) -{ - struct request_queue *q = rq->q; - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_allow_merge_fn) - return e->ops->elevator_allow_merge_fn(q, rq, bio); - - return 1; -} - -/* - * can we safely merge with this request? - */ -int elv_rq_merge_ok(struct request *rq, struct bio *bio) -{ - if (!rq_mergeable(rq)) - return 0; - - /* - * Don't merge file system requests and discard requests - */ - if (bio_discard(bio) != bio_discard(rq->bio)) - return 0; - - /* - * different data direction or already started, don't merge - */ - if (bio_data_dir(bio) != rq_data_dir(rq)) - return 0; - - /* - * must be same device and not a special request - */ - if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special) - return 0; - - /* - * only merge integrity protected bio into ditto rq - */ - if (bio_integrity(bio) != blk_integrity_rq(rq)) - return 0; - - if (!elv_iosched_allow_merge(rq, bio)) - return 0; - - return 1; -} -EXPORT_SYMBOL(elv_rq_merge_ok); - -static inline int elv_try_merge(struct request *__rq, struct bio *bio) -{ - int ret = ELEVATOR_NO_MERGE; - - /* - * we can merge and sequence is ok, check if it's possible - */ - if (elv_rq_merge_ok(__rq, bio)) { - if (__rq->sector + __rq->nr_sectors == bio->bi_sector) - ret = ELEVATOR_BACK_MERGE; - else if (__rq->sector - bio_sectors(bio) == bio->bi_sector) - ret = ELEVATOR_FRONT_MERGE; - } - - return ret; -} - -static struct elevator_type *elevator_find(const char *name) -{ - struct elevator_type *e; - - list_for_each_entry(e, &elv_list, list) { - if (!strcmp(e->elevator_name, name)) - return e; - } - - return NULL; -} - -static void elevator_put(struct elevator_type *e) -{ - module_put(e->elevator_owner); -} - -static struct elevator_type *elevator_get(const char *name) -{ - struct elevator_type *e; - - spin_lock(&elv_list_lock); - - e = elevator_find(name); - if (!e) { - char elv[ELV_NAME_MAX + strlen("-iosched")]; - - spin_unlock(&elv_list_lock); - - if (!strcmp(name, "anticipatory")) - sprintf(elv, "as-iosched"); - else - sprintf(elv, "%s-iosched", name); - - request_module("%s", elv); - spin_lock(&elv_list_lock); - e = elevator_find(name); - } - - if (e && !try_module_get(e->elevator_owner)) - e = NULL; - - spin_unlock(&elv_list_lock); - - return e; -} - -static void *elevator_init_queue(struct request_queue *q, - struct elevator_queue *eq) -{ - return eq->ops->elevator_init_fn(q); -} - -static void elevator_attach(struct request_queue *q, struct elevator_queue *eq, - void *data) -{ - q->elevator = eq; - eq->elevator_data = data; -} - -static char chosen_elevator[16]; - -static int __init elevator_setup(char *str) -{ - /* - * Be backwards-compatible with previous kernels, so users - * won't get the wrong elevator. - */ - if (!strcmp(str, "as")) - strcpy(chosen_elevator, "anticipatory"); - else - strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); - return 1; -} - -__setup("elevator=", elevator_setup); - -static struct kobj_type elv_ktype; - -static struct elevator_queue *elevator_alloc(struct request_queue *q, - struct elevator_type *e) -{ - struct elevator_queue *eq; - int i; - - eq = kmalloc_node(sizeof(*eq), GFP_KERNEL | __GFP_ZERO, q->node); - if (unlikely(!eq)) - goto err; - - eq->ops = &e->ops; - eq->elevator_type = e; - kobject_init(&eq->kobj, &elv_ktype); - mutex_init(&eq->sysfs_lock); - - eq->hash = kmalloc_node(sizeof(struct hlist_head) * ELV_HASH_ENTRIES, - GFP_KERNEL, q->node); - if (!eq->hash) - goto err; - - for (i = 0; i < ELV_HASH_ENTRIES; i++) - INIT_HLIST_HEAD(&eq->hash[i]); - - return eq; -err: - kfree(eq); - elevator_put(e); - return NULL; -} - -static void elevator_release(struct kobject *kobj) -{ - struct elevator_queue *e; - - e = container_of(kobj, struct elevator_queue, kobj); - elevator_put(e->elevator_type); - kfree(e->hash); - kfree(e); -} - -int elevator_init(struct request_queue *q, char *name) -{ - struct elevator_type *e = NULL; - struct elevator_queue *eq; - int ret = 0; - void *data; - - INIT_LIST_HEAD(&q->queue_head); - q->last_merge = NULL; - q->end_sector = 0; - q->boundary_rq = NULL; - - if (name) { - e = elevator_get(name); - if (!e) - return -EINVAL; - } - - if (!e && *chosen_elevator) { - e = elevator_get(chosen_elevator); - if (!e) - printk(KERN_ERR "I/O scheduler %s not found\n", - chosen_elevator); - } - - if (!e) { - e = elevator_get(CONFIG_DEFAULT_IOSCHED); - if (!e) { - printk(KERN_ERR - "Default I/O scheduler not found. " \ - "Using noop.\n"); - e = elevator_get("noop"); - } - } - - eq = elevator_alloc(q, e); - if (!eq) - return -ENOMEM; - - data = elevator_init_queue(q, eq); - if (!data) { - kobject_put(&eq->kobj); - return -ENOMEM; - } - - elevator_attach(q, eq, data); - return ret; -} -EXPORT_SYMBOL(elevator_init); - -void elevator_exit(struct elevator_queue *e) -{ - mutex_lock(&e->sysfs_lock); - if (e->ops->elevator_exit_fn) - e->ops->elevator_exit_fn(e); - e->ops = NULL; - mutex_unlock(&e->sysfs_lock); - - kobject_put(&e->kobj); -} -EXPORT_SYMBOL(elevator_exit); - -static void elv_activate_rq(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_activate_req_fn) - e->ops->elevator_activate_req_fn(q, rq); -} - -static void elv_deactivate_rq(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_deactivate_req_fn) - e->ops->elevator_deactivate_req_fn(q, rq); -} - -static inline void __elv_rqhash_del(struct request *rq) -{ - hlist_del_init(&rq->hash); -} - -static void elv_rqhash_del(struct request_queue *q, struct request *rq) -{ - if (ELV_ON_HASH(rq)) - __elv_rqhash_del(rq); -} - -static void elv_rqhash_add(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - BUG_ON(ELV_ON_HASH(rq)); - hlist_add_head(&rq->hash, &e->hash[ELV_HASH_FN(rq_hash_key(rq))]); -} - -static void elv_rqhash_reposition(struct request_queue *q, struct request *rq) -{ - __elv_rqhash_del(rq); - elv_rqhash_add(q, rq); -} - -static struct request *elv_rqhash_find(struct request_queue *q, sector_t offset) -{ - struct elevator_queue *e = q->elevator; - struct hlist_head *hash_list = &e->hash[ELV_HASH_FN(offset)]; - struct hlist_node *entry, *next; - struct request *rq; - - hlist_for_each_entry_safe(rq, entry, next, hash_list, hash) { - BUG_ON(!ELV_ON_HASH(rq)); - - if (unlikely(!rq_mergeable(rq))) { - __elv_rqhash_del(rq); - continue; - } - - if (rq_hash_key(rq) == offset) - return rq; - } - - return NULL; -} - -/* - * RB-tree support functions for inserting/lookup/removal of requests - * in a sorted RB tree. - */ -struct request *elv_rb_add(struct rb_root *root, struct request *rq) -{ - struct rb_node **p = &root->rb_node; - struct rb_node *parent = NULL; - struct request *__rq; - - while (*p) { - parent = *p; - __rq = rb_entry(parent, struct request, rb_node); - - if (rq->sector < __rq->sector) - p = &(*p)->rb_left; - else if (rq->sector > __rq->sector) - p = &(*p)->rb_right; - else - return __rq; - } - - rb_link_node(&rq->rb_node, parent, p); - rb_insert_color(&rq->rb_node, root); - return NULL; -} -EXPORT_SYMBOL(elv_rb_add); - -void elv_rb_del(struct rb_root *root, struct request *rq) -{ - BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); - rb_erase(&rq->rb_node, root); - RB_CLEAR_NODE(&rq->rb_node); -} -EXPORT_SYMBOL(elv_rb_del); - -struct request *elv_rb_find(struct rb_root *root, sector_t sector) -{ - struct rb_node *n = root->rb_node; - struct request *rq; - - while (n) { - rq = rb_entry(n, struct request, rb_node); - - if (sector < rq->sector) - n = n->rb_left; - else if (sector > rq->sector) - n = n->rb_right; - else - return rq; - } - - return NULL; -} -EXPORT_SYMBOL(elv_rb_find); - -/* - * Insert rq into dispatch queue of q. Queue lock must be held on - * entry. rq is sort instead into the dispatch queue. To be used by - * specific elevators. - */ -void elv_dispatch_sort(struct request_queue *q, struct request *rq) -{ - sector_t boundary; - struct list_head *entry; - int stop_flags; - - if (q->last_merge == rq) - q->last_merge = NULL; - - elv_rqhash_del(q, rq); - - q->nr_sorted--; - - boundary = q->end_sector; - stop_flags = REQ_SOFTBARRIER | REQ_HARDBARRIER | REQ_STARTED; - list_for_each_prev(entry, &q->queue_head) { - struct request *pos = list_entry_rq(entry); - - if (blk_discard_rq(rq) != blk_discard_rq(pos)) - break; - if (rq_data_dir(rq) != rq_data_dir(pos)) - break; - if (pos->cmd_flags & stop_flags) - break; - if (rq->sector >= boundary) { - if (pos->sector < boundary) - continue; - } else { - if (pos->sector >= boundary) - break; - } - if (rq->sector >= pos->sector) - break; - } - - list_add(&rq->queuelist, entry); -} -EXPORT_SYMBOL(elv_dispatch_sort); - -/* - * Insert rq into dispatch queue of q. Queue lock must be held on - * entry. rq is added to the back of the dispatch queue. To be used by - * specific elevators. - */ -void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) -{ - if (q->last_merge == rq) - q->last_merge = NULL; - - elv_rqhash_del(q, rq); - - q->nr_sorted--; - - q->end_sector = rq_end_sector(rq); - q->boundary_rq = rq; - list_add_tail(&rq->queuelist, &q->queue_head); -} -EXPORT_SYMBOL(elv_dispatch_add_tail); - -int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) -{ - struct elevator_queue *e = q->elevator; - struct request *__rq; - int ret; - - /* - * First try one-hit cache. - */ - if (q->last_merge) { - ret = elv_try_merge(q->last_merge, bio); - if (ret != ELEVATOR_NO_MERGE) { - *req = q->last_merge; - return ret; - } - } - - if (blk_queue_nomerges(q)) - return ELEVATOR_NO_MERGE; - - /* - * See if our hash lookup can find a potential backmerge. - */ - __rq = elv_rqhash_find(q, bio->bi_sector); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - *req = __rq; - return ELEVATOR_BACK_MERGE; - } - - if (e->ops->elevator_merge_fn) - return e->ops->elevator_merge_fn(q, req, bio); - - return ELEVATOR_NO_MERGE; -} - -void elv_merged_request(struct request_queue *q, struct request *rq, int type) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_merged_fn) - e->ops->elevator_merged_fn(q, rq, type); - - if (type == ELEVATOR_BACK_MERGE) - elv_rqhash_reposition(q, rq); - - q->last_merge = rq; -} - -void elv_merge_requests(struct request_queue *q, struct request *rq, - struct request *next) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_merge_req_fn) - e->ops->elevator_merge_req_fn(q, rq, next); - - elv_rqhash_reposition(q, rq); - elv_rqhash_del(q, next); - - q->nr_sorted--; - q->last_merge = rq; -} - -void elv_requeue_request(struct request_queue *q, struct request *rq) -{ - /* - * it already went through dequeue, we need to decrement the - * in_flight count again - */ - if (blk_account_rq(rq)) { - q->in_flight--; - if (blk_sorted_rq(rq)) - elv_deactivate_rq(q, rq); - } - - rq->cmd_flags &= ~REQ_STARTED; - - elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE); -} - -static void elv_drain_elevator(struct request_queue *q) -{ - static int printed; - while (q->elevator->ops->elevator_dispatch_fn(q, 1)) - ; - if (q->nr_sorted == 0) - return; - if (printed++ < 10) { - printk(KERN_ERR "%s: forced dispatching is broken " - "(nr_sorted=%u), please report this\n", - q->elevator->elevator_type->elevator_name, q->nr_sorted); - } -} - -void elv_insert(struct request_queue *q, struct request *rq, int where) -{ - struct list_head *pos; - unsigned ordseq; - int unplug_it = 1; - - trace_block_rq_insert(q, rq); - - rq->q = q; - - switch (where) { - case ELEVATOR_INSERT_FRONT: - rq->cmd_flags |= REQ_SOFTBARRIER; - - list_add(&rq->queuelist, &q->queue_head); - break; - - case ELEVATOR_INSERT_BACK: - rq->cmd_flags |= REQ_SOFTBARRIER; - elv_drain_elevator(q); - list_add_tail(&rq->queuelist, &q->queue_head); - /* - * We kick the queue here for the following reasons. - * - The elevator might have returned NULL previously - * to delay requests and returned them now. As the - * queue wasn't empty before this request, ll_rw_blk - * won't run the queue on return, resulting in hang. - * - Usually, back inserted requests won't be merged - * with anything. There's no point in delaying queue - * processing. - */ - blk_remove_plug(q); - blk_start_queueing(q); - break; - - case ELEVATOR_INSERT_SORT: - BUG_ON(!blk_fs_request(rq) && !blk_discard_rq(rq)); - rq->cmd_flags |= REQ_SORTED; - q->nr_sorted++; - if (rq_mergeable(rq)) { - elv_rqhash_add(q, rq); - if (!q->last_merge) - q->last_merge = rq; - } - - /* - * Some ioscheds (cfq) run q->request_fn directly, so - * rq cannot be accessed after calling - * elevator_add_req_fn. - */ - q->elevator->ops->elevator_add_req_fn(q, rq); - break; - - case ELEVATOR_INSERT_REQUEUE: - /* - * If ordered flush isn't in progress, we do front - * insertion; otherwise, requests should be requeued - * in ordseq order. - */ - rq->cmd_flags |= REQ_SOFTBARRIER; - - /* - * Most requeues happen because of a busy condition, - * don't force unplug of the queue for that case. - */ - unplug_it = 0; - - if (q->ordseq == 0) { - list_add(&rq->queuelist, &q->queue_head); - break; - } - - ordseq = blk_ordered_req_seq(rq); - - list_for_each(pos, &q->queue_head) { - struct request *pos_rq = list_entry_rq(pos); - if (ordseq <= blk_ordered_req_seq(pos_rq)) - break; - } - - list_add_tail(&rq->queuelist, pos); - break; - - default: - printk(KERN_ERR "%s: bad insertion point %d\n", - __func__, where); - BUG(); - } - - if (unplug_it && blk_queue_plugged(q)) { - int nrq = q->rq.count[READ] + q->rq.count[WRITE] - - q->in_flight; - - if (nrq >= q->unplug_thresh) - __generic_unplug_device(q); - } -} - -void __elv_add_request(struct request_queue *q, struct request *rq, int where, - int plug) -{ - if (q->ordcolor) - rq->cmd_flags |= REQ_ORDERED_COLOR; - - if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { - /* - * toggle ordered color - */ - if (blk_barrier_rq(rq)) - q->ordcolor ^= 1; - - /* - * barriers implicitly indicate back insertion - */ - if (where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; - - /* - * this request is scheduling boundary, update - * end_sector - */ - if (blk_fs_request(rq) || blk_discard_rq(rq)) { - q->end_sector = rq_end_sector(rq); - q->boundary_rq = rq; - } - } else if (!(rq->cmd_flags & REQ_ELVPRIV) && - where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; - - if (plug) - blk_plug_device(q); - - elv_insert(q, rq, where); -} -EXPORT_SYMBOL(__elv_add_request); - -void elv_add_request(struct request_queue *q, struct request *rq, int where, - int plug) -{ - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - __elv_add_request(q, rq, where, plug); - spin_unlock_irqrestore(q->queue_lock, flags); -} -EXPORT_SYMBOL(elv_add_request); - -static inline struct request *__elv_next_request(struct request_queue *q) -{ - struct request *rq; - - while (1) { - while (!list_empty(&q->queue_head)) { - rq = list_entry_rq(q->queue_head.next); - if (blk_do_ordered(q, &rq)) - return rq; - } - - if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) - return NULL; - } -} - -struct request *elv_next_request(struct request_queue *q) -{ - struct request *rq; - int ret; - - while ((rq = __elv_next_request(q)) != NULL) { - if (!(rq->cmd_flags & REQ_STARTED)) { - /* - * This is the first time the device driver - * sees this request (possibly after - * requeueing). Notify IO scheduler. - */ - if (blk_sorted_rq(rq)) - elv_activate_rq(q, rq); - - /* - * just mark as started even if we don't start - * it, a request that has been delayed should - * not be passed by new incoming requests - */ - rq->cmd_flags |= REQ_STARTED; - trace_block_rq_issue(q, rq); - } - - if (!q->boundary_rq || q->boundary_rq == rq) { - q->end_sector = rq_end_sector(rq); - q->boundary_rq = NULL; - } - - if (rq->cmd_flags & REQ_DONTPREP) - break; - - if (q->dma_drain_size && rq->data_len) { - /* - * make sure space for the drain appears we - * know we can do this because max_hw_segments - * has been adjusted to be one fewer than the - * device can handle - */ - rq->nr_phys_segments++; - } - - if (!q->prep_rq_fn) - break; - - ret = q->prep_rq_fn(q, rq); - if (ret == BLKPREP_OK) { - break; - } else if (ret == BLKPREP_DEFER) { - /* - * the request may have been (partially) prepped. - * we need to keep this request in the front to - * avoid resource deadlock. REQ_STARTED will - * prevent other fs requests from passing this one. - */ - if (q->dma_drain_size && rq->data_len && - !(rq->cmd_flags & REQ_DONTPREP)) { - /* - * remove the space for the drain we added - * so that we don't add it again - */ - --rq->nr_phys_segments; - } - - rq = NULL; - break; - } else if (ret == BLKPREP_KILL) { - rq->cmd_flags |= REQ_QUIET; - __blk_end_request(rq, -EIO, blk_rq_bytes(rq)); - } else { - printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); - break; - } - } - - return rq; -} -EXPORT_SYMBOL(elv_next_request); - -void elv_dequeue_request(struct request_queue *q, struct request *rq) -{ - BUG_ON(list_empty(&rq->queuelist)); - BUG_ON(ELV_ON_HASH(rq)); - - list_del_init(&rq->queuelist); - - /* - * the time frame between a request being removed from the lists - * and to it is freed is accounted as io that is in progress at - * the driver side. - */ - if (blk_account_rq(rq)) - q->in_flight++; -} - -int elv_queue_empty(struct request_queue *q) -{ - struct elevator_queue *e = q->elevator; - - if (!list_empty(&q->queue_head)) - return 0; - - if (e->ops->elevator_queue_empty_fn) - return e->ops->elevator_queue_empty_fn(q); - - return 1; -} -EXPORT_SYMBOL(elv_queue_empty); - -struct request *elv_latter_request(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_latter_req_fn) - return e->ops->elevator_latter_req_fn(q, rq); - return NULL; -} - -struct request *elv_former_request(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_former_req_fn) - return e->ops->elevator_former_req_fn(q, rq); - return NULL; -} - -int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_set_req_fn) - return e->ops->elevator_set_req_fn(q, rq, gfp_mask); - - rq->elevator_private = NULL; - return 0; -} - -void elv_put_request(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_put_req_fn) - e->ops->elevator_put_req_fn(rq); -} - -int elv_may_queue(struct request_queue *q, int rw) -{ - struct elevator_queue *e = q->elevator; - - if (e->ops->elevator_may_queue_fn) - return e->ops->elevator_may_queue_fn(q, rw); - - return ELV_MQUEUE_MAY; -} - -void elv_abort_queue(struct request_queue *q) -{ - struct request *rq; - - while (!list_empty(&q->queue_head)) { - rq = list_entry_rq(q->queue_head.next); - rq->cmd_flags |= REQ_QUIET; - trace_block_rq_abort(q, rq); - __blk_end_request(rq, -EIO, blk_rq_bytes(rq)); - } -} -EXPORT_SYMBOL(elv_abort_queue); - -void elv_completed_request(struct request_queue *q, struct request *rq) -{ - struct elevator_queue *e = q->elevator; - - /* - * request is released from the driver, io must be done - */ - if (blk_account_rq(rq)) { - q->in_flight--; - if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) - e->ops->elevator_completed_req_fn(q, rq); - } - - /* - * Check if the queue is waiting for fs requests to be - * drained for flush sequence. - */ - if (unlikely(q->ordseq)) { - struct request *next = NULL; - - if (!list_empty(&q->queue_head)) - next = list_entry_rq(q->queue_head.next); - - if (!q->in_flight && - blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN && - (!next || blk_ordered_req_seq(next) > QUEUE_ORDSEQ_DRAIN)) { - blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0); - blk_start_queueing(q); - } - } -} - -#define to_elv(atr) container_of((atr), struct elv_fs_entry, attr) - -static ssize_t -elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) -{ - struct elv_fs_entry *entry = to_elv(attr); - struct elevator_queue *e; - ssize_t error; - - if (!entry->show) - return -EIO; - - e = container_of(kobj, struct elevator_queue, kobj); - mutex_lock(&e->sysfs_lock); - error = e->ops ? entry->show(e, page) : -ENOENT; - mutex_unlock(&e->sysfs_lock); - return error; -} - -static ssize_t -elv_attr_store(struct kobject *kobj, struct attribute *attr, - const char *page, size_t length) -{ - struct elv_fs_entry *entry = to_elv(attr); - struct elevator_queue *e; - ssize_t error; - - if (!entry->store) - return -EIO; - - e = container_of(kobj, struct elevator_queue, kobj); - mutex_lock(&e->sysfs_lock); - error = e->ops ? entry->store(e, page, length) : -ENOENT; - mutex_unlock(&e->sysfs_lock); - return error; -} - -static struct sysfs_ops elv_sysfs_ops = { - .show = elv_attr_show, - .store = elv_attr_store, -}; - -static struct kobj_type elv_ktype = { - .sysfs_ops = &elv_sysfs_ops, - .release = elevator_release, -}; - -int elv_register_queue(struct request_queue *q) -{ - struct elevator_queue *e = q->elevator; - int error; - - error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); - if (!error) { - struct elv_fs_entry *attr = e->elevator_type->elevator_attrs; - if (attr) { - while (attr->attr.name) { - if (sysfs_create_file(&e->kobj, &attr->attr)) - break; - attr++; - } - } - kobject_uevent(&e->kobj, KOBJ_ADD); - } - return error; -} - -static void __elv_unregister_queue(struct elevator_queue *e) -{ - kobject_uevent(&e->kobj, KOBJ_REMOVE); - kobject_del(&e->kobj); -} - -void elv_unregister_queue(struct request_queue *q) -{ - if (q) - __elv_unregister_queue(q->elevator); -} - -void elv_register(struct elevator_type *e) -{ - char *def = ""; - - spin_lock(&elv_list_lock); - BUG_ON(elevator_find(e->elevator_name)); - list_add_tail(&e->list, &elv_list); - spin_unlock(&elv_list_lock); - - if (!strcmp(e->elevator_name, chosen_elevator) || - (!*chosen_elevator && - !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) - def = " (default)"; - - printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, - def); -} -EXPORT_SYMBOL_GPL(elv_register); - -void elv_unregister(struct elevator_type *e) -{ - struct task_struct *g, *p; - - /* - * Iterate every thread in the process to remove the io contexts. - */ - if (e->ops.trim) { - read_lock(&tasklist_lock); - do_each_thread(g, p) { - task_lock(p); - if (p->io_context) - e->ops.trim(p->io_context); - task_unlock(p); - } while_each_thread(g, p); - read_unlock(&tasklist_lock); - } - - spin_lock(&elv_list_lock); - list_del_init(&e->list); - spin_unlock(&elv_list_lock); -} -EXPORT_SYMBOL_GPL(elv_unregister); - -/* - * switch to new_e io scheduler. be careful not to introduce deadlocks - - * we don't free the old io scheduler, before we have allocated what we - * need for the new one. this way we have a chance of going back to the old - * one, if the new one fails init for some reason. - */ -static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) -{ - struct elevator_queue *old_elevator, *e; - void *data; - - /* - * Allocate new elevator - */ - e = elevator_alloc(q, new_e); - if (!e) - return 0; - - data = elevator_init_queue(q, e); - if (!data) { - kobject_put(&e->kobj); - return 0; - } - - /* - * Turn on BYPASS and drain all requests w/ elevator private data - */ - spin_lock_irq(q->queue_lock); - - queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); - - elv_drain_elevator(q); - - while (q->rq.elvpriv) { - blk_start_queueing(q); - spin_unlock_irq(q->queue_lock); - msleep(10); - spin_lock_irq(q->queue_lock); - elv_drain_elevator(q); - } - - /* - * Remember old elevator. - */ - old_elevator = q->elevator; - - /* - * attach and start new elevator - */ - elevator_attach(q, e, data); - - spin_unlock_irq(q->queue_lock); - - __elv_unregister_queue(old_elevator); - - if (elv_register_queue(q)) - goto fail_register; - - /* - * finally exit old elevator and turn off BYPASS. - */ - elevator_exit(old_elevator); - spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); - - blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name); - - return 1; - -fail_register: - /* - * switch failed, exit the new io scheduler and reattach the old - * one again (along with re-adding the sysfs dir) - */ - elevator_exit(e); - q->elevator = old_elevator; - elv_register_queue(q); - - spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); - - return 0; -} - -ssize_t elv_iosched_store(struct request_queue *q, const char *name, - size_t count) -{ - char elevator_name[ELV_NAME_MAX]; - struct elevator_type *e; - - strlcpy(elevator_name, name, sizeof(elevator_name)); - strstrip(elevator_name); - - e = elevator_get(elevator_name); - if (!e) { - printk(KERN_ERR "elevator: type %s not found\n", elevator_name); - return -EINVAL; - } - - if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) { - elevator_put(e); - return count; - } - - if (!elevator_switch(q, e)) - printk(KERN_ERR "elevator: switch to %s failed\n", - elevator_name); - return count; -} - -ssize_t elv_iosched_show(struct request_queue *q, char *name) -{ - struct elevator_queue *e = q->elevator; - struct elevator_type *elv = e->elevator_type; - struct elevator_type *__e; - int len = 0; - - spin_lock(&elv_list_lock); - list_for_each_entry(__e, &elv_list, list) { - if (!strcmp(elv->elevator_name, __e->elevator_name)) - len += sprintf(name+len, "[%s] ", elv->elevator_name); - else - len += sprintf(name+len, "%s ", __e->elevator_name); - } - spin_unlock(&elv_list_lock); - - len += sprintf(len+name, "\n"); - return len; -} - -struct request *elv_rb_former_request(struct request_queue *q, - struct request *rq) -{ - struct rb_node *rbprev = rb_prev(&rq->rb_node); - - if (rbprev) - return rb_entry_rq(rbprev); - - return NULL; -} -EXPORT_SYMBOL(elv_rb_former_request); - -struct request *elv_rb_latter_request(struct request_queue *q, - struct request *rq) -{ - struct rb_node *rbnext = rb_next(&rq->rb_node); - - if (rbnext) - return rb_entry_rq(rbnext); - - return NULL; -} -EXPORT_SYMBOL(elv_rb_latter_request); |