X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Felevator.c;h=1975b619c86d4e7f4212116c7fd3dd11b2a090eb;hb=ec60e4f6749daf535329dac571293cf19c627aff;hp=39dcccc82ada5b71e3105a8b7e9d8389fc9000b6;hpb=797e7dbbee0a91fa1349192f18ad5c454997d876;p=safe%2Fjmp%2Flinux-2.6 diff --git a/block/elevator.c b/block/elevator.c index 39dcccc..1975b61 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -3,7 +3,7 @@ * * Copyright (C) 2000 Andrea Arcangeli SuSE * - * 30042000 Jens Axboe : + * 30042000 Jens Axboe : * * 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: @@ -27,44 +27,88 @@ #include #include #include -#include #include #include #include #include #include +#include +#include +#include -#include +#include + +#include "blk.h" static DEFINE_SPINLOCK(elv_list_lock); static LIST_HEAD(elv_list); /* + * 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) (blk_rq_pos(rq) + blk_rq_sectors(rq)) + +/* + * 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? */ -inline int elv_rq_merge_ok(struct request *rq, struct bio *bio) +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_rw_flagged(bio, BIO_RW_DISCARD) != + bio_rw_flagged(rq->bio, BIO_RW_DISCARD)) + return 0; + + /* * different data direction or already started, don't merge */ if (bio_data_dir(bio) != rq_data_dir(rq)) return 0; /* - * same device and no special stuff set, merge is ok + * must be same device and not a special request */ - if (rq->rq_disk == bio->bi_bdev->bd_disk && - !rq->waiting && !rq->special) - return 1; + if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special) + return 0; - 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); -inline int elv_try_merge(struct request *__rq, struct bio *bio) +static inline int elv_try_merge(struct request *__rq, struct bio *bio) { int ret = ELEVATOR_NO_MERGE; @@ -72,33 +116,25 @@ inline int elv_try_merge(struct request *__rq, struct bio *bio) * 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) + if (blk_rq_pos(__rq) + blk_rq_sectors(__rq) == bio->bi_sector) ret = ELEVATOR_BACK_MERGE; - else if (__rq->sector - bio_sectors(bio) == bio->bi_sector) + else if (blk_rq_pos(__rq) - bio_sectors(bio) == bio->bi_sector) ret = ELEVATOR_FRONT_MERGE; } return ret; } -EXPORT_SYMBOL(elv_try_merge); static struct elevator_type *elevator_find(const char *name) { - struct elevator_type *e = NULL; - struct list_head *entry; - - list_for_each(entry, &elv_list) { - struct elevator_type *__e; - - __e = list_entry(entry, struct elevator_type, list); + struct elevator_type *e; - if (!strcmp(__e->elevator_name, name)) { - e = __e; - break; - } + list_for_each_entry(e, &elv_list, list) { + if (!strcmp(e->elevator_name, name)) + return e; } - return e; + return NULL; } static void elevator_put(struct elevator_type *e) @@ -110,148 +146,342 @@ static struct elevator_type *elevator_get(const char *name) { struct elevator_type *e; - spin_lock_irq(&elv_list_lock); + 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_irq(&elv_list_lock); + spin_unlock(&elv_list_lock); return e; } -static int elevator_attach(request_queue_t *q, struct elevator_type *e, - struct elevator_queue *eq) +static void *elevator_init_queue(struct request_queue *q, + struct elevator_queue *eq) { - int ret = 0; - - memset(eq, 0, sizeof(*eq)); - eq->ops = &e->ops; - eq->elevator_type = e; + return eq->ops->elevator_init_fn(q); +} +static void elevator_attach(struct request_queue *q, struct elevator_queue *eq, + void *data) +{ q->elevator = eq; - - if (eq->ops->elevator_init_fn) - ret = eq->ops->elevator_init_fn(q, eq); - - return ret; + eq->elevator_data = data; } static char chosen_elevator[16]; -static void elevator_setup_default(void) +static int __init elevator_setup(char *str) { - struct elevator_type *e; - /* - * If default has not been set, use the compiled-in selection. + * Be backwards-compatible with previous kernels, so users + * won't get the wrong elevator. */ - if (!chosen_elevator[0]) - strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED); - - /* - * If the given scheduler is not available, fall back to no-op. - */ - if ((e = elevator_find(chosen_elevator))) - elevator_put(e); + if (!strcmp(str, "as")) + strcpy(chosen_elevator, "anticipatory"); else - strcpy(chosen_elevator, "noop"); + strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); + return 1; } -static int __init elevator_setup(char *str) +__setup("elevator=", elevator_setup); + +static struct kobj_type elv_ktype; + +static struct elevator_queue *elevator_alloc(struct request_queue *q, + struct elevator_type *e) { - strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); - return 0; + 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; } -__setup("elevator=", elevator_setup); +static void elevator_release(struct kobject *kobj) +{ + struct elevator_queue *e; -int elevator_init(request_queue_t *q, char *name) + 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; - elevator_setup_default(); + if (name) { + e = elevator_get(name); + if (!e) + return -EINVAL; + } - if (!name) - name = chosen_elevator; + if (!e && *chosen_elevator) { + e = elevator_get(chosen_elevator); + if (!e) + printk(KERN_ERR "I/O scheduler %s not found\n", + chosen_elevator); + } - e = elevator_get(name); - if (!e) - return -EINVAL; + 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 = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); - if (!eq) { - elevator_put(e); + eq = elevator_alloc(q, e); + if (!eq) return -ENOMEM; - } - ret = elevator_attach(q, e, eq); - if (ret) { - kfree(eq); - elevator_put(e); + 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(elevator_t *e) +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); - elevator_put(e->elevator_type); - e->elevator_type = NULL; - kfree(e); + kobject_put(&e->kobj); +} +EXPORT_SYMBOL(elevator_exit); + +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 (blk_rq_pos(rq) < blk_rq_pos(__rq)) + p = &(*p)->rb_left; + else if (blk_rq_pos(rq) > blk_rq_pos(__rq)) + 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 < blk_rq_pos(rq)) + n = n->rb_left; + else if (sector > blk_rq_pos(rq)) + 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. If sort != 0, rq is sort-inserted; otherwise, rq will be - * appended to the dispatch queue. To be used by specific elevators. + * entry. rq is sort instead into the dispatch queue. To be used by + * specific elevators. */ -void elv_dispatch_sort(request_queue_t *q, struct request *rq) +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 (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED)) + if (blk_discard_rq(rq) != blk_discard_rq(pos)) + break; + if (rq_data_dir(rq) != rq_data_dir(pos)) break; - if (rq->sector >= boundary) { - if (pos->sector < boundary) + if (pos->cmd_flags & stop_flags) + break; + if (blk_rq_pos(rq) >= boundary) { + if (blk_rq_pos(pos) < boundary) continue; } else { - if (pos->sector >= boundary) + if (blk_rq_pos(pos) >= boundary) break; } - if (rq->sector >= pos->sector) + if (blk_rq_pos(rq) >= blk_rq_pos(pos)) 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(request_queue_t *q, struct request **req, struct bio *bio) +int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) { - elevator_t *e = q->elevator; + 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) { @@ -260,54 +490,70 @@ int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) } } + 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(request_queue_t *q, struct request *rq) +void elv_merged_request(struct request_queue *q, struct request *rq, int type) { - elevator_t *e = q->elevator; + struct elevator_queue *e = q->elevator; if (e->ops->elevator_merged_fn) - e->ops->elevator_merged_fn(q, rq); + 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(request_queue_t *q, struct request *rq, +void elv_merge_requests(struct request_queue *q, struct request *rq, struct request *next) { - elevator_t *e = q->elevator; + struct elevator_queue *e = q->elevator; if (e->ops->elevator_merge_req_fn) e->ops->elevator_merge_req_fn(q, rq, next); - q->nr_sorted--; + elv_rqhash_reposition(q, rq); + elv_rqhash_del(q, next); + + q->nr_sorted--; q->last_merge = rq; } -void elv_requeue_request(request_queue_t *q, struct request *rq) +void elv_requeue_request(struct request_queue *q, struct request *rq) { - elevator_t *e = q->elevator; - /* * 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) && e->ops->elevator_deactivate_req_fn) - e->ops->elevator_deactivate_req_fn(q, rq); + q->in_flight[rq_is_sync(rq)]--; + if (blk_sorted_rq(rq)) + elv_deactivate_rq(q, rq); } - rq->flags &= ~REQ_STARTED; + rq->cmd_flags &= ~REQ_STARTED; - __elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE, 0); + elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE); } -static void elv_drain_elevator(request_queue_t *q) +void elv_drain_elevator(struct request_queue *q) { static int printed; while (q->elevator->ops->elevator_dispatch_fn(q, 1)) @@ -321,51 +567,53 @@ static void elv_drain_elevator(request_queue_t *q) } } -void __elv_add_request(request_queue_t *q, struct request *rq, int where, - int plug) +/* + * Call with queue lock held, interrupts disabled + */ +void elv_quiesce_start(struct request_queue *q) { - struct list_head *pos; - unsigned ordseq; + if (!q->elevator) + return; - if (q->ordcolor) - rq->flags |= REQ_ORDERED_COLOR; + queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); - if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { - /* - * toggle ordered color - */ - q->ordcolor ^= 1; + /* + * make sure we don't have any requests in flight + */ + elv_drain_elevator(q); + while (q->rq.elvpriv) { + __blk_run_queue(q); + spin_unlock_irq(q->queue_lock); + msleep(10); + spin_lock_irq(q->queue_lock); + elv_drain_elevator(q); + } +} - /* - * barriers implicitly indicate back insertion - */ - if (where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; +void elv_quiesce_end(struct request_queue *q) +{ + queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); +} - /* - * this request is scheduling boundary, update end_sector - */ - if (blk_fs_request(rq)) { - q->end_sector = rq_end_sector(rq); - q->boundary_rq = rq; - } - } else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; +void elv_insert(struct request_queue *q, struct request *rq, int where) +{ + struct list_head *pos; + unsigned ordseq; + int unplug_it = 1; - if (plug) - blk_plug_device(q); + trace_block_rq_insert(q, rq); rq->q = q; switch (where) { case ELEVATOR_INSERT_FRONT: - rq->flags |= REQ_SOFTBARRIER; + rq->cmd_flags |= REQ_SOFTBARRIER; list_add(&rq->queuelist, &q->queue_head); break; case ELEVATOR_INSERT_BACK: - rq->flags |= REQ_SOFTBARRIER; + rq->cmd_flags |= REQ_SOFTBARRIER; elv_drain_elevator(q); list_add_tail(&rq->queuelist, &q->queue_head); /* @@ -378,16 +626,19 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, * with anything. There's no point in delaying queue * processing. */ - blk_remove_plug(q); - q->request_fn(q); + __blk_run_queue(q); break; case ELEVATOR_INSERT_SORT: - BUG_ON(!blk_fs_request(rq)); - rq->flags |= REQ_SORTED; + BUG_ON(!blk_fs_request(rq) && !blk_discard_rq(rq)); + rq->cmd_flags |= REQ_SORTED; q->nr_sorted++; - if (q->last_merge == NULL && rq_mergeable(rq)) - q->last_merge = rq; + 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 @@ -402,7 +653,13 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, * insertion; otherwise, requests should be requeued * in ordseq order. */ - rq->flags |= REQ_SOFTBARRIER; + 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); @@ -422,129 +679,71 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, default: printk(KERN_ERR "%s: bad insertion point %d\n", - __FUNCTION__, where); + __func__, where); BUG(); } - if (blk_queue_plugged(q)) { - int nrq = q->rq.count[READ] + q->rq.count[WRITE] - - q->in_flight; + if (unplug_it && blk_queue_plugged(q)) { + int nrq = q->rq.count[BLK_RW_SYNC] + q->rq.count[BLK_RW_ASYNC] + - queue_in_flight(q); if (nrq >= q->unplug_thresh) __generic_unplug_device(q); } } -void elv_add_request(request_queue_t *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); -} - -static inline struct request *__elv_next_request(request_queue_t *q) +void __elv_add_request(struct request_queue *q, struct request *rq, int where, + int plug) { - 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; - } -} + if (q->ordcolor) + rq->cmd_flags |= REQ_ORDERED_COLOR; -struct request *elv_next_request(request_queue_t *q) -{ - struct request *rq; - int ret; + if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { + /* + * toggle ordered color + */ + if (blk_barrier_rq(rq)) + q->ordcolor ^= 1; - while ((rq = __elv_next_request(q)) != NULL) { - if (!(rq->flags & REQ_STARTED)) { - elevator_t *e = q->elevator; - - /* - * This is the first time the device driver - * sees this request (possibly after - * requeueing). Notify IO scheduler. - */ - if (blk_sorted_rq(rq) && - e->ops->elevator_activate_req_fn) - e->ops->elevator_activate_req_fn(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->flags |= REQ_STARTED; - } + /* + * barriers implicitly indicate back insertion + */ + if (where == ELEVATOR_INSERT_SORT) + where = ELEVATOR_INSERT_BACK; - if (!q->boundary_rq || q->boundary_rq == rq) { + /* + * 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 = NULL; + q->boundary_rq = rq; } + } else if (!(rq->cmd_flags & REQ_ELVPRIV) && + where == ELEVATOR_INSERT_SORT) + where = ELEVATOR_INSERT_BACK; - if ((rq->flags & REQ_DONTPREP) || !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. - */ - rq = NULL; - break; - } else if (ret == BLKPREP_KILL) { - int nr_bytes = rq->hard_nr_sectors << 9; - - if (!nr_bytes) - nr_bytes = rq->data_len; - - blkdev_dequeue_request(rq); - rq->flags |= REQ_QUIET; - end_that_request_chunk(rq, 0, nr_bytes); - end_that_request_last(rq, 0); - } else { - printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__, - ret); - break; - } - } + if (plug) + blk_plug_device(q); - return rq; + elv_insert(q, rq, where); } +EXPORT_SYMBOL(__elv_add_request); -void elv_dequeue_request(request_queue_t *q, struct request *rq) +void elv_add_request(struct request_queue *q, struct request *rq, int where, + int plug) { - BUG_ON(list_empty(&rq->queuelist)); - - list_del_init(&rq->queuelist); + unsigned long flags; - /* - * 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++; + 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); -int elv_queue_empty(request_queue_t *q) +int elv_queue_empty(struct request_queue *q) { - elevator_t *e = q->elevator; + struct elevator_queue *e = q->elevator; if (!list_empty(&q->queue_head)) return 0; @@ -554,119 +753,200 @@ int elv_queue_empty(request_queue_t *q) return 1; } +EXPORT_SYMBOL(elv_queue_empty); -struct request *elv_latter_request(request_queue_t *q, struct request *rq) +struct request *elv_latter_request(struct request_queue *q, struct request *rq) { - elevator_t *e = q->elevator; + 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(request_queue_t *q, struct request *rq) +struct request *elv_former_request(struct request_queue *q, struct request *rq) { - elevator_t *e = q->elevator; + 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(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) +int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) { - elevator_t *e = q->elevator; + struct elevator_queue *e = q->elevator; if (e->ops->elevator_set_req_fn) - return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask); + return e->ops->elevator_set_req_fn(q, rq, gfp_mask); rq->elevator_private = NULL; return 0; } -void elv_put_request(request_queue_t *q, struct request *rq) +void elv_put_request(struct request_queue *q, struct request *rq) { - elevator_t *e = q->elevator; + struct elevator_queue *e = q->elevator; if (e->ops->elevator_put_req_fn) - e->ops->elevator_put_req_fn(q, rq); + e->ops->elevator_put_req_fn(rq); } -int elv_may_queue(request_queue_t *q, int rw, struct bio *bio) +int elv_may_queue(struct request_queue *q, int rw) { - elevator_t *e = q->elevator; + struct elevator_queue *e = q->elevator; if (e->ops->elevator_may_queue_fn) - return e->ops->elevator_may_queue_fn(q, rw, bio); + return e->ops->elevator_may_queue_fn(q, rw); return ELV_MQUEUE_MAY; } -void elv_completed_request(request_queue_t *q, struct request *rq) +void elv_abort_queue(struct request_queue *q) { - elevator_t *e = q->elevator; + 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); + /* + * Mark this request as started so we don't trigger + * any debug logic in the end I/O path. + */ + blk_start_request(rq); + __blk_end_request_all(rq, -EIO); + } +} +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)) { - struct request *first_rq = list_entry_rq(q->queue_head.next); + q->in_flight[rq_is_sync(rq)]--; + if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) + e->ops->elevator_completed_req_fn(q, rq); + } - q->in_flight--; + /* + * Check if the queue is waiting for fs requests to be + * drained for flush sequence. + */ + if (unlikely(q->ordseq)) { + struct request *next = NULL; - /* - * Check if the queue is waiting for fs requests to be - * drained for flush sequence. - */ - if (q->ordseq && q->in_flight == 0 && + if (!list_empty(&q->queue_head)) + next = list_entry_rq(q->queue_head.next); + + if (!queue_in_flight(q) && blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN && - blk_ordered_req_seq(first_rq) > QUEUE_ORDSEQ_DRAIN) { + (!next || blk_ordered_req_seq(next) > QUEUE_ORDSEQ_DRAIN)) { blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0); - q->request_fn(q); + __blk_run_queue(q); } - - if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) - e->ops->elevator_completed_req_fn(q, rq); } } -int elv_register_queue(struct request_queue *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) { - elevator_t *e = q->elevator; + 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; +} - e->kobj.parent = kobject_get(&q->kobj); - if (!e->kobj.parent) - return -EBUSY; +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; +} - snprintf(e->kobj.name, KOBJ_NAME_LEN, "%s", "iosched"); - e->kobj.ktype = e->elevator_type->elevator_ktype; +static struct sysfs_ops elv_sysfs_ops = { + .show = elv_attr_show, + .store = elv_attr_store, +}; - return kobject_register(&e->kobj); +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) { - elevator_t *e = q->elevator; - kobject_unregister(&e->kobj); - kobject_put(&q->kobj); - } + if (q) + __elv_unregister_queue(q->elevator); } -int elv_register(struct elevator_type *e) +void elv_register(struct elevator_type *e) { - spin_lock_irq(&elv_list_lock); - if (elevator_find(e->elevator_name)) - BUG(); + char *def = ""; + + spin_lock(&elv_list_lock); + BUG_ON(elevator_find(e->elevator_name)); list_add_tail(&e->list, &elv_list); - spin_unlock_irq(&elv_list_lock); + spin_unlock(&elv_list_lock); - printk(KERN_INFO "io scheduler %s registered", e->elevator_name); - if (!strcmp(e->elevator_name, chosen_elevator)) - printk(" (default)"); - printk("\n"); - return 0; + 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); @@ -677,25 +957,20 @@ void elv_unregister(struct elevator_type *e) /* * Iterate every thread in the process to remove the io contexts. */ - read_lock(&tasklist_lock); - do_each_thread(g, p) { - struct io_context *ioc = p->io_context; - if (ioc && ioc->cic) { - ioc->cic->exit(ioc->cic); - ioc->cic->dtor(ioc->cic); - ioc->cic = NULL; - } - if (ioc && ioc->aic) { - ioc->aic->exit(ioc->aic); - ioc->aic->dtor(ioc->aic); - ioc->aic = NULL; - } - } while_each_thread(g, p); - read_unlock(&tasklist_lock); + 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_irq(&elv_list_lock); + spin_lock(&elv_list_lock); list_del_init(&e->list); - spin_unlock_irq(&elv_list_lock); + spin_unlock(&elv_list_lock); } EXPORT_SYMBOL_GPL(elv_unregister); @@ -705,48 +980,43 @@ EXPORT_SYMBOL_GPL(elv_unregister); * 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 void elevator_switch(request_queue_t *q, struct elevator_type *new_e) +static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) { - elevator_t *old_elevator, *e; + struct elevator_queue *old_elevator, *e; + void *data; /* * Allocate new elevator */ - e = kmalloc(sizeof(elevator_t), GFP_KERNEL); + e = elevator_alloc(q, new_e); if (!e) - goto error; + 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); - - set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - - elv_drain_elevator(q); - - while (q->rq.elvpriv) { - blk_remove_plug(q); - q->request_fn(q); - spin_unlock_irq(q->queue_lock); - msleep(10); - spin_lock_irq(q->queue_lock); - elv_drain_elevator(q); - } - - spin_unlock_irq(q->queue_lock); + elv_quiesce_start(q); /* - * unregister old elevator data + * Remember old elevator. */ - elv_unregister_queue(q); old_elevator = q->elevator; /* * attach and start new elevator */ - if (elevator_attach(q, new_e, e)) - goto fail; + elevator_attach(q, e, data); + + spin_unlock_irq(q->queue_lock); + + __elv_unregister_queue(old_elevator); if (elv_register_queue(q)) goto fail_register; @@ -755,8 +1025,13 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e) * finally exit old elevator and turn off BYPASS. */ elevator_exit(old_elevator); - clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - return; + spin_lock_irq(q->queue_lock); + elv_quiesce_end(q); + spin_unlock_irq(q->queue_lock); + + blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name); + + return 1; fail_register: /* @@ -764,29 +1039,27 @@ fail_register: * one again (along with re-adding the sysfs dir) */ elevator_exit(e); - e = NULL; -fail: q->elevator = old_elevator; elv_register_queue(q); - clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - kfree(e); -error: - elevator_put(new_e); - printk(KERN_ERR "elevator: switch to %s failed\n",new_e->elevator_name); + + 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(request_queue_t *q, const char *name, size_t count) +ssize_t elv_iosched_store(struct request_queue *q, const char *name, + size_t count) { char elevator_name[ELV_NAME_MAX]; - size_t len; struct elevator_type *e; - elevator_name[sizeof(elevator_name) - 1] = '\0'; - strncpy(elevator_name, name, sizeof(elevator_name) - 1); - len = strlen(elevator_name); + if (!q->elevator) + return count; - if (len && elevator_name[len - 1] == '\n') - elevator_name[len - 1] = '\0'; + strlcpy(elevator_name, name, sizeof(elevator_name)); + strstrip(elevator_name); e = elevator_get(elevator_name); if (!e) { @@ -799,40 +1072,57 @@ ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count) return count; } - elevator_switch(q, e); + if (!elevator_switch(q, e)) + printk(KERN_ERR "elevator: switch to %s failed\n", + elevator_name); return count; } -ssize_t elv_iosched_show(request_queue_t *q, char *name) +ssize_t elv_iosched_show(struct request_queue *q, char *name) { - elevator_t *e = q->elevator; - struct elevator_type *elv = e->elevator_type; - struct list_head *entry; + struct elevator_queue *e = q->elevator; + struct elevator_type *elv; + struct elevator_type *__e; int len = 0; - spin_lock_irq(q->queue_lock); - list_for_each(entry, &elv_list) { - struct elevator_type *__e; + if (!q->elevator) + return sprintf(name, "none\n"); - __e = list_entry(entry, struct elevator_type, list); + elv = e->elevator_type; + + 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_irq(q->queue_lock); + spin_unlock(&elv_list_lock); len += sprintf(len+name, "\n"); return len; } -EXPORT_SYMBOL(elv_dispatch_sort); -EXPORT_SYMBOL(elv_add_request); -EXPORT_SYMBOL(__elv_add_request); -EXPORT_SYMBOL(elv_requeue_request); -EXPORT_SYMBOL(elv_next_request); -EXPORT_SYMBOL(elv_dequeue_request); -EXPORT_SYMBOL(elv_queue_empty); -EXPORT_SYMBOL(elv_completed_request); -EXPORT_SYMBOL(elevator_exit); -EXPORT_SYMBOL(elevator_init); +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);