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-rw-r--r--drivers/block/elevator.c43
-rw-r--r--include/linux/blkdev.h3
2 files changed, 21 insertions, 25 deletions
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
index 29d6c8237ab3..415144372c75 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)
83} 83}
84EXPORT_SYMBOL(elv_try_merge); 84EXPORT_SYMBOL(elv_try_merge);
85 85
86inline int elv_try_last_merge(request_queue_t *q, struct bio *bio)
87{
88 if (q->last_merge)
89 return elv_try_merge(q->last_merge, bio);
90
91 return ELEVATOR_NO_MERGE;
92}
93EXPORT_SYMBOL(elv_try_last_merge);
94
95static struct elevator_type *elevator_find(const char *name) 86static struct elevator_type *elevator_find(const char *name)
96{ 87{
97 struct elevator_type *e = NULL; 88 struct elevator_type *e = NULL;
@@ -239,6 +230,9 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq)
239 unsigned max_back; 230 unsigned max_back;
240 struct list_head *entry; 231 struct list_head *entry;
241 232
233 if (q->last_merge == rq)
234 q->last_merge = NULL;
235
242 boundary = q->end_sector; 236 boundary = q->end_sector;
243 max_back = q->max_back_kb * 2; 237 max_back = q->max_back_kb * 2;
244 boundary = boundary > max_back ? boundary - max_back : 0; 238 boundary = boundary > max_back ? boundary - max_back : 0;
@@ -265,6 +259,15 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq)
265int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) 259int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
266{ 260{
267 elevator_t *e = q->elevator; 261 elevator_t *e = q->elevator;
262 int ret;
263
264 if (q->last_merge) {
265 ret = elv_try_merge(q->last_merge, bio);
266 if (ret != ELEVATOR_NO_MERGE) {
267 *req = q->last_merge;
268 return ret;
269 }
270 }
268 271
269 if (e->ops->elevator_merge_fn) 272 if (e->ops->elevator_merge_fn)
270 return e->ops->elevator_merge_fn(q, req, bio); 273 return e->ops->elevator_merge_fn(q, req, bio);
@@ -278,6 +281,8 @@ void elv_merged_request(request_queue_t *q, struct request *rq)
278 281
279 if (e->ops->elevator_merged_fn) 282 if (e->ops->elevator_merged_fn)
280 e->ops->elevator_merged_fn(q, rq); 283 e->ops->elevator_merged_fn(q, rq);
284
285 q->last_merge = rq;
281} 286}
282 287
283void elv_merge_requests(request_queue_t *q, struct request *rq, 288void 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,
285{ 290{
286 elevator_t *e = q->elevator; 291 elevator_t *e = q->elevator;
287 292
288 if (q->last_merge == next)
289 q->last_merge = NULL;
290
291 if (e->ops->elevator_merge_req_fn) 293 if (e->ops->elevator_merge_req_fn)
292 e->ops->elevator_merge_req_fn(q, rq, next); 294 e->ops->elevator_merge_req_fn(q, rq, next);
295
296 q->last_merge = rq;
293} 297}
294 298
295void elv_requeue_request(request_queue_t *q, struct request *rq) 299void 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,
384 BUG_ON(!blk_fs_request(rq)); 388 BUG_ON(!blk_fs_request(rq));
385 rq->flags |= REQ_SORTED; 389 rq->flags |= REQ_SORTED;
386 q->elevator->ops->elevator_add_req_fn(q, rq); 390 q->elevator->ops->elevator_add_req_fn(q, rq);
391 if (q->last_merge == NULL && rq_mergeable(rq))
392 q->last_merge = rq;
387 break; 393 break;
388 394
389 default: 395 default:
@@ -462,9 +468,6 @@ struct request *elv_next_request(request_queue_t *q)
462 rq->flags |= REQ_STARTED; 468 rq->flags |= REQ_STARTED;
463 } 469 }
464 470
465 if (rq == q->last_merge)
466 q->last_merge = NULL;
467
468 if (!q->boundary_rq || q->boundary_rq == rq) { 471 if (!q->boundary_rq || q->boundary_rq == rq) {
469 q->end_sector = rq_end_sector(rq); 472 q->end_sector = rq_end_sector(rq);
470 q->boundary_rq = NULL; 473 q->boundary_rq = NULL;
@@ -518,16 +521,6 @@ void elv_dequeue_request(request_queue_t *q, struct request *rq)
518 */ 521 */
519 if (blk_account_rq(rq)) 522 if (blk_account_rq(rq))
520 q->in_flight++; 523 q->in_flight++;
521
522 /*
523 * the main clearing point for q->last_merge is on retrieval of
524 * request by driver (it calls elv_next_request()), but it _can_
525 * also happen here if a request is added to the queue but later
526 * deleted without ever being given to driver (merged with another
527 * request).
528 */
529 if (rq == q->last_merge)
530 q->last_merge = NULL;
531} 524}
532 525
533int elv_queue_empty(request_queue_t *q) 526int elv_queue_empty(request_queue_t *q)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a2e496f285a4..bd55b1df8997 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -630,6 +630,9 @@ static inline void blkdev_dequeue_request(struct request *req)
630static inline void elv_dispatch_add_tail(struct request_queue *q, 630static inline void elv_dispatch_add_tail(struct request_queue *q,
631 struct request *rq) 631 struct request *rq)
632{ 632{
633 if (q->last_merge == rq)
634 q->last_merge = NULL;
635
633 q->end_sector = rq_end_sector(rq); 636 q->end_sector = rq_end_sector(rq);
634 q->boundary_rq = rq; 637 q->boundary_rq = rq;
635 list_add_tail(&rq->queuelist, &q->queue_head); 638 list_add_tail(&rq->queuelist, &q->queue_head);