From 8922e16cf6269e668123acb1ae1fdc62b7a3a4fc Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 20 Oct 2005 16:23:44 +0200 Subject: [PATCH] 01/05 Implement generic dispatch queue Implements generic dispatch queue which can replace all dispatch queues implemented by each iosched. This reduces code duplication, eases enforcing semantics over dispatch queue, and simplifies specific ioscheds. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/elevator.c | 242 +++++++++++++++++++++++++++++++++-------------- 1 file changed, 170 insertions(+), 72 deletions(-) (limited to 'drivers/block/elevator.c') diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 4144f30d82a..a27555908d3 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -40,6 +40,11 @@ static DEFINE_SPINLOCK(elv_list_lock); static LIST_HEAD(elv_list); +static inline sector_t rq_last_sector(struct request *rq) +{ + return rq->sector + rq->nr_sectors; +} + /* * can we safely merge with this request? */ @@ -143,6 +148,9 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e, INIT_LIST_HEAD(&q->queue_head); q->last_merge = NULL; q->elevator = eq; + q->last_sector = 0; + q->boundary_rq = NULL; + q->max_back_kb = 0; if (eq->ops->elevator_init_fn) ret = eq->ops->elevator_init_fn(q, eq); @@ -225,6 +233,48 @@ void elevator_exit(elevator_t *e) kfree(e); } +/* + * 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. + */ +void elv_dispatch_insert(request_queue_t *q, struct request *rq, int sort) +{ + sector_t boundary; + unsigned max_back; + struct list_head *entry; + + if (!sort) { + /* Specific elevator is performing sort. Step away. */ + q->last_sector = rq_last_sector(rq); + q->boundary_rq = rq; + list_add_tail(&rq->queuelist, &q->queue_head); + return; + } + + boundary = q->last_sector; + max_back = q->max_back_kb * 2; + boundary = boundary > max_back ? boundary - max_back : 0; + + list_for_each_prev(entry, &q->queue_head) { + struct request *pos = list_entry_rq(entry); + + if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED)) + 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); +} + int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; @@ -255,13 +305,7 @@ void elv_merge_requests(request_queue_t *q, struct request *rq, e->ops->elevator_merge_req_fn(q, rq, next); } -/* - * For careful internal use by the block layer. Essentially the same as - * a requeue in that it tells the io scheduler that this request is not - * active in the driver or hardware anymore, but we don't want the request - * added back to the scheduler. Function is not exported. - */ -void elv_deactivate_request(request_queue_t *q, struct request *rq) +void elv_requeue_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; @@ -269,19 +313,14 @@ void elv_deactivate_request(request_queue_t *q, struct request *rq) * it already went through dequeue, we need to decrement the * in_flight count again */ - if (blk_account_rq(rq)) + 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); + } rq->flags &= ~REQ_STARTED; - if (e->ops->elevator_deactivate_req_fn) - e->ops->elevator_deactivate_req_fn(q, rq); -} - -void elv_requeue_request(request_queue_t *q, struct request *rq) -{ - elv_deactivate_request(q, rq); - /* * if this is the flush, requeue the original instead and drop the flush */ @@ -290,55 +329,89 @@ void elv_requeue_request(request_queue_t *q, struct request *rq) rq = rq->end_io_data; } - /* - * the request is prepped and may have some resources allocated. - * allowing unprepped requests to pass this one may cause resource - * deadlock. turn on softbarrier. - */ - rq->flags |= REQ_SOFTBARRIER; - - /* - * if iosched has an explicit requeue hook, then use that. otherwise - * just put the request at the front of the queue - */ - if (q->elevator->ops->elevator_requeue_req_fn) - q->elevator->ops->elevator_requeue_req_fn(q, rq); - else - __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); + __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); } void __elv_add_request(request_queue_t *q, struct request *rq, int where, int plug) { - /* - * barriers implicitly indicate back insertion - */ - if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER) && - where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; + if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { + /* + * barriers implicitly indicate back insertion + */ + if (where == ELEVATOR_INSERT_SORT) + where = ELEVATOR_INSERT_BACK; + + /* + * this request is scheduling boundary, update last_sector + */ + if (blk_fs_request(rq)) { + q->last_sector = rq_last_sector(rq); + q->boundary_rq = rq; + } + } if (plug) blk_plug_device(q); rq->q = q; - if (!test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags)) { - q->elevator->ops->elevator_add_req_fn(q, rq, where); - - if (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); - } - } else + if (unlikely(test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags))) { /* * if drain is set, store the request "locally". when the drain * is finished, the requests will be handed ordered to the io * scheduler */ list_add_tail(&rq->queuelist, &q->drain_list); + return; + } + + switch (where) { + case ELEVATOR_INSERT_FRONT: + rq->flags |= REQ_SOFTBARRIER; + + list_add(&rq->queuelist, &q->queue_head); + break; + + case ELEVATOR_INSERT_BACK: + rq->flags |= REQ_SOFTBARRIER; + + while (q->elevator->ops->elevator_dispatch_fn(q, 1)) + ; + 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); + q->request_fn(q); + break; + + case ELEVATOR_INSERT_SORT: + BUG_ON(!blk_fs_request(rq)); + rq->flags |= REQ_SORTED; + q->elevator->ops->elevator_add_req_fn(q, rq); + break; + + default: + printk(KERN_ERR "%s: bad insertion point %d\n", + __FUNCTION__, where); + BUG(); + } + + if (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(request_queue_t *q, struct request *rq, int where, @@ -353,13 +426,19 @@ void elv_add_request(request_queue_t *q, struct request *rq, int where, static inline struct request *__elv_next_request(request_queue_t *q) { - struct request *rq = q->elevator->ops->elevator_next_req_fn(q); + struct request *rq; + + if (unlikely(list_empty(&q->queue_head) && + !q->elevator->ops->elevator_dispatch_fn(q, 0))) + return NULL; + + rq = list_entry_rq(q->queue_head.next); /* * if this is a barrier write and the device has to issue a * flush sequence to support it, check how far we are */ - if (rq && blk_fs_request(rq) && blk_barrier_rq(rq)) { + if (blk_fs_request(rq) && blk_barrier_rq(rq)) { BUG_ON(q->ordered == QUEUE_ORDERED_NONE); if (q->ordered == QUEUE_ORDERED_FLUSH && @@ -376,16 +455,34 @@ struct request *elv_next_request(request_queue_t *q) int ret; while ((rq = __elv_next_request(q)) != NULL) { - /* - * 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; + 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; + } if (rq == q->last_merge) q->last_merge = NULL; + if (!q->boundary_rq || q->boundary_rq == rq) { + q->last_sector = rq_last_sector(rq); + q->boundary_rq = NULL; + } + if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn) break; @@ -396,9 +493,9 @@ struct request *elv_next_request(request_queue_t *q) /* * the request may have been (partially) prepped. * we need to keep this request in the front to - * avoid resource deadlock. turn on softbarrier. + * avoid resource deadlock. REQ_STARTED will + * prevent other fs requests from passing this one. */ - rq->flags |= REQ_SOFTBARRIER; rq = NULL; break; } else if (ret == BLKPREP_KILL) { @@ -421,16 +518,16 @@ struct request *elv_next_request(request_queue_t *q) return rq; } -void elv_remove_request(request_queue_t *q, struct request *rq) +void elv_dequeue_request(request_queue_t *q, struct request *rq) { - elevator_t *e = q->elevator; + BUG_ON(list_empty(&rq->queuelist)); + + 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. note that we only account requests that the - * driver has seen (REQ_STARTED set), to avoid false accounting - * for request-request merges + * the driver side. */ if (blk_account_rq(rq)) q->in_flight++; @@ -444,19 +541,19 @@ void elv_remove_request(request_queue_t *q, struct request *rq) */ if (rq == q->last_merge) q->last_merge = NULL; - - if (e->ops->elevator_remove_req_fn) - e->ops->elevator_remove_req_fn(q, rq); } int elv_queue_empty(request_queue_t *q) { elevator_t *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 list_empty(&q->queue_head); + return 1; } struct request *elv_latter_request(request_queue_t *q, struct request *rq) @@ -528,11 +625,11 @@ void elv_completed_request(request_queue_t *q, struct request *rq) /* * request is released from the driver, io must be done */ - if (blk_account_rq(rq)) + if (blk_account_rq(rq)) { q->in_flight--; - - if (e->ops->elevator_completed_req_fn) - e->ops->elevator_completed_req_fn(q, rq); + 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) @@ -705,11 +802,12 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) return len; } +EXPORT_SYMBOL(elv_dispatch_insert); EXPORT_SYMBOL(elv_add_request); EXPORT_SYMBOL(__elv_add_request); EXPORT_SYMBOL(elv_requeue_request); EXPORT_SYMBOL(elv_next_request); -EXPORT_SYMBOL(elv_remove_request); +EXPORT_SYMBOL(elv_dequeue_request); EXPORT_SYMBOL(elv_queue_empty); EXPORT_SYMBOL(elv_completed_request); EXPORT_SYMBOL(elevator_exit); -- cgit v1.2.3-70-g09d2 From 1b47f531e244e339b648dfff071c086f936e49e1 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 20 Oct 2005 16:37:00 +0200 Subject: [PATCH] generic dispatch fixes - Split elv_dispatch_insert() into two functions - Rename rq_last_sector() to rq_end_sector() Signed-off-by: Jens Axboe --- drivers/block/elevator.c | 33 ++++++++++++--------------------- include/linux/blkdev.h | 13 ++++++++++++- include/linux/elevator.h | 4 +++- 3 files changed, 27 insertions(+), 23 deletions(-) (limited to 'drivers/block/elevator.c') diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index a27555908d3..237e43d760c 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -40,11 +40,6 @@ static DEFINE_SPINLOCK(elv_list_lock); static LIST_HEAD(elv_list); -static inline sector_t rq_last_sector(struct request *rq) -{ - return rq->sector + rq->nr_sectors; -} - /* * can we safely merge with this request? */ @@ -148,7 +143,7 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e, INIT_LIST_HEAD(&q->queue_head); q->last_merge = NULL; q->elevator = eq; - q->last_sector = 0; + q->end_sector = 0; q->boundary_rq = NULL; q->max_back_kb = 0; @@ -233,29 +228,25 @@ void elevator_exit(elevator_t *e) kfree(e); } +void elv_dispatch_insert_tail(request_queue_t *q, struct request *rq) +{ +} + /* * 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. */ -void elv_dispatch_insert(request_queue_t *q, struct request *rq, int sort) +void elv_dispatch_sort(request_queue_t *q, struct request *rq) { sector_t boundary; unsigned max_back; struct list_head *entry; - if (!sort) { - /* Specific elevator is performing sort. Step away. */ - q->last_sector = rq_last_sector(rq); - q->boundary_rq = rq; - list_add_tail(&rq->queuelist, &q->queue_head); - return; - } - - boundary = q->last_sector; + boundary = q->end_sector; max_back = q->max_back_kb * 2; boundary = boundary > max_back ? boundary - max_back : 0; - + list_for_each_prev(entry, &q->queue_head) { struct request *pos = list_entry_rq(entry); @@ -343,10 +334,10 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, where = ELEVATOR_INSERT_BACK; /* - * this request is scheduling boundary, update last_sector + * this request is scheduling boundary, update end_sector */ if (blk_fs_request(rq)) { - q->last_sector = rq_last_sector(rq); + q->end_sector = rq_end_sector(rq); q->boundary_rq = rq; } } @@ -479,7 +470,7 @@ struct request *elv_next_request(request_queue_t *q) q->last_merge = NULL; if (!q->boundary_rq || q->boundary_rq == rq) { - q->last_sector = rq_last_sector(rq); + q->end_sector = rq_end_sector(rq); q->boundary_rq = NULL; } @@ -802,7 +793,7 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) return len; } -EXPORT_SYMBOL(elv_dispatch_insert); +EXPORT_SYMBOL(elv_dispatch_sort); EXPORT_SYMBOL(elv_add_request); EXPORT_SYMBOL(__elv_add_request); EXPORT_SYMBOL(elv_requeue_request); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 2c7b9154927..a2e496f285a 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -337,7 +337,7 @@ struct request_queue /* * Dispatch queue sorting */ - sector_t last_sector; + sector_t end_sector; struct request *boundary_rq; unsigned int max_back_kb; @@ -624,6 +624,17 @@ static inline void blkdev_dequeue_request(struct request *req) elv_dequeue_request(req->q, req); } +/* + * This should be in elevator.h, but that requires pulling in rq and q + */ +static inline void elv_dispatch_add_tail(struct request_queue *q, + struct request *rq) +{ + q->end_sector = rq_end_sector(rq); + q->boundary_rq = rq; + list_add_tail(&rq->queuelist, &q->queue_head); +} + /* * Access functions for manipulating queue properties */ diff --git a/include/linux/elevator.h b/include/linux/elevator.h index 76f4f692074..f9b5ec38121 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -79,7 +79,7 @@ struct elevator_queue /* * block elevator interface */ -extern void elv_dispatch_insert(request_queue_t *, struct request *, int); +extern void elv_dispatch_sort(request_queue_t *, struct request *); extern void elv_add_request(request_queue_t *, struct request *, int, int); extern void __elv_add_request(request_queue_t *, struct request *, int, int); extern int elv_merge(request_queue_t *, struct request **, struct bio *); @@ -140,4 +140,6 @@ enum { ELV_MQUEUE_MUST, }; +#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) + #endif -- cgit v1.2.3-70-g09d2 From d9ebb192aa13a026edc6faff137dcb14f2c91731 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 20 Oct 2005 16:37:38 +0200 Subject: [PATCH] elevator: leftover function declaration Signed-off-by: Jens Axboe --- drivers/block/elevator.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers/block/elevator.c') diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 237e43d760c..29d6c8237ab 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -228,10 +228,6 @@ void elevator_exit(elevator_t *e) kfree(e); } -void elv_dispatch_insert_tail(request_queue_t *q, struct request *rq) -{ -} - /* * 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 -- cgit v1.2.3-70-g09d2 From 06b86245c052963029bfd9020ca1f08ceb66f85a Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 20 Oct 2005 16:46:23 +0200 Subject: [PATCH] 03/05 move last_merge handlin into generic elevator code Currently, both generic elevator code and specific ioscheds participate in the management and usage of last_merge. This and the following patches move last_merge handling into generic elevator code. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/elevator.c | 43 ++++++++++++++++++------------------------- include/linux/blkdev.h | 3 +++ 2 files changed, 21 insertions(+), 25 deletions(-) (limited to 'drivers/block/elevator.c') diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 29d6c8237ab..415144372c7 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -83,15 +83,6 @@ inline int elv_try_merge(struct request *__rq, struct bio *bio) } EXPORT_SYMBOL(elv_try_merge); -inline int elv_try_last_merge(request_queue_t *q, struct bio *bio) -{ - if (q->last_merge) - return elv_try_merge(q->last_merge, bio); - - return ELEVATOR_NO_MERGE; -} -EXPORT_SYMBOL(elv_try_last_merge); - static struct elevator_type *elevator_find(const char *name) { struct elevator_type *e = NULL; @@ -239,6 +230,9 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq) unsigned max_back; struct list_head *entry; + if (q->last_merge == rq) + q->last_merge = NULL; + boundary = q->end_sector; max_back = q->max_back_kb * 2; boundary = boundary > max_back ? boundary - max_back : 0; @@ -265,6 +259,15 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq) int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; + int ret; + + if (q->last_merge) { + ret = elv_try_merge(q->last_merge, bio); + if (ret != ELEVATOR_NO_MERGE) { + *req = q->last_merge; + return ret; + } + } if (e->ops->elevator_merge_fn) return e->ops->elevator_merge_fn(q, req, bio); @@ -278,6 +281,8 @@ void elv_merged_request(request_queue_t *q, struct request *rq) if (e->ops->elevator_merged_fn) e->ops->elevator_merged_fn(q, rq); + + q->last_merge = rq; } void elv_merge_requests(request_queue_t *q, struct request *rq, @@ -285,11 +290,10 @@ void elv_merge_requests(request_queue_t *q, struct request *rq, { elevator_t *e = q->elevator; - if (q->last_merge == next) - q->last_merge = NULL; - if (e->ops->elevator_merge_req_fn) e->ops->elevator_merge_req_fn(q, rq, next); + + q->last_merge = rq; } void elv_requeue_request(request_queue_t *q, struct request *rq) @@ -384,6 +388,8 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, BUG_ON(!blk_fs_request(rq)); rq->flags |= REQ_SORTED; q->elevator->ops->elevator_add_req_fn(q, rq); + if (q->last_merge == NULL && rq_mergeable(rq)) + q->last_merge = rq; break; default: @@ -462,9 +468,6 @@ struct request *elv_next_request(request_queue_t *q) rq->flags |= REQ_STARTED; } - if (rq == q->last_merge) - q->last_merge = NULL; - if (!q->boundary_rq || q->boundary_rq == rq) { q->end_sector = rq_end_sector(rq); q->boundary_rq = NULL; @@ -518,16 +521,6 @@ void elv_dequeue_request(request_queue_t *q, struct request *rq) */ if (blk_account_rq(rq)) q->in_flight++; - - /* - * the main clearing point for q->last_merge is on retrieval of - * request by driver (it calls elv_next_request()), but it _can_ - * also happen here if a request is added to the queue but later - * deleted without ever being given to driver (merged with another - * request). - */ - if (rq == q->last_merge) - q->last_merge = NULL; } int elv_queue_empty(request_queue_t *q) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index a2e496f285a..bd55b1df899 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -630,6 +630,9 @@ static inline void blkdev_dequeue_request(struct request *req) static inline void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) { + if (q->last_merge == rq) + q->last_merge = NULL; + q->end_sector = rq_end_sector(rq); q->boundary_rq = rq; list_add_tail(&rq->queuelist, &q->queue_head); -- cgit v1.2.3-70-g09d2 From cb19833dccb32f97cacbfff834b53523915f13f6 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 24 Oct 2005 08:35:58 +0200 Subject: [BLOCK] kill generic max_back_kb handling This patch kills max_back_kb handling from elv_dispatch_sort() and kills max_back_kb field from struct request_queue. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/elevator.c | 6 +----- include/linux/blkdev.h | 1 - 2 files changed, 1 insertion(+), 6 deletions(-) (limited to 'drivers/block/elevator.c') diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 415144372c7..af2388e73f6 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -136,7 +136,6 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e, q->elevator = eq; q->end_sector = 0; q->boundary_rq = NULL; - q->max_back_kb = 0; if (eq->ops->elevator_init_fn) ret = eq->ops->elevator_init_fn(q, eq); @@ -227,16 +226,13 @@ void elevator_exit(elevator_t *e) void elv_dispatch_sort(request_queue_t *q, struct request *rq) { sector_t boundary; - unsigned max_back; struct list_head *entry; if (q->last_merge == rq) q->last_merge = NULL; boundary = q->end_sector; - max_back = q->max_back_kb * 2; - boundary = boundary > max_back ? boundary - max_back : 0; - + list_for_each_prev(entry, &q->queue_head) { struct request *pos = list_entry_rq(entry); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bd55b1df899..159dbcd2eb5 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -339,7 +339,6 @@ struct request_queue */ sector_t end_sector; struct request *boundary_rq; - unsigned int max_back_kb; /* * Auto-unplugging state -- cgit v1.2.3-70-g09d2