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authorKiyoshi Ueda <k-ueda@ct.jp.nec.com>2009-12-10 18:52:16 -0500
committerAlasdair G Kergon <agk@redhat.com>2009-12-10 18:52:16 -0500
commitb4324feeae304ae39e631a254d238a7d63be004b (patch)
tree12495362c9301129912a8d706de0f6cdb7de8ccf /drivers/md
parent9f518b27cf682dd5155a4c1679d52cd4b5be82f2 (diff)
dm: use md pending for in flight IO counting
This patch changes the counter for the number of in_flight I/Os to md->pending from q->in_flight in preparation for a later patch. No functional change. Request-based dm used q->in_flight to count the number of in-flight clones assuming the counter is always incremented for an in-flight original request and original:clone is 1:1 relationship. However, it this no longer true for barrier requests. So use md->pending to count the number of in-flight clones. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm.c46
1 files changed, 18 insertions, 28 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 634b1daab2d..01d741a0c07 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -727,23 +727,16 @@ static void end_clone_bio(struct bio *clone, int error)
727 * the md may be freed in dm_put() at the end of this function. 727 * the md may be freed in dm_put() at the end of this function.
728 * Or do dm_get() before calling this function and dm_put() later. 728 * Or do dm_get() before calling this function and dm_put() later.
729 */ 729 */
730static void rq_completed(struct mapped_device *md, int run_queue) 730static void rq_completed(struct mapped_device *md, int rw, int run_queue)
731{ 731{
732 int wakeup_waiters = 0; 732 atomic_dec(&md->pending[rw]);
733 struct request_queue *q = md->queue;
734 unsigned long flags;
735
736 spin_lock_irqsave(q->queue_lock, flags);
737 if (!queue_in_flight(q))
738 wakeup_waiters = 1;
739 spin_unlock_irqrestore(q->queue_lock, flags);
740 733
741 /* nudge anyone waiting on suspend queue */ 734 /* nudge anyone waiting on suspend queue */
742 if (wakeup_waiters) 735 if (!md_in_flight(md))
743 wake_up(&md->wait); 736 wake_up(&md->wait);
744 737
745 if (run_queue) 738 if (run_queue)
746 blk_run_queue(q); 739 blk_run_queue(md->queue);
747 740
748 /* 741 /*
749 * dm_put() must be at the end of this function. See the comment above 742 * dm_put() must be at the end of this function. See the comment above
@@ -774,6 +767,7 @@ static void dm_unprep_request(struct request *rq)
774 */ 767 */
775void dm_requeue_unmapped_request(struct request *clone) 768void dm_requeue_unmapped_request(struct request *clone)
776{ 769{
770 int rw = rq_data_dir(clone);
777 struct dm_rq_target_io *tio = clone->end_io_data; 771 struct dm_rq_target_io *tio = clone->end_io_data;
778 struct mapped_device *md = tio->md; 772 struct mapped_device *md = tio->md;
779 struct request *rq = tio->orig; 773 struct request *rq = tio->orig;
@@ -788,7 +782,7 @@ void dm_requeue_unmapped_request(struct request *clone)
788 blk_requeue_request(q, rq); 782 blk_requeue_request(q, rq);
789 spin_unlock_irqrestore(q->queue_lock, flags); 783 spin_unlock_irqrestore(q->queue_lock, flags);
790 784
791 rq_completed(md, 0); 785 rq_completed(md, rw, 0);
792} 786}
793EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request); 787EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
794 788
@@ -827,6 +821,7 @@ static void start_queue(struct request_queue *q)
827 */ 821 */
828static void dm_end_request(struct request *clone, int error) 822static void dm_end_request(struct request *clone, int error)
829{ 823{
824 int rw = rq_data_dir(clone);
830 struct dm_rq_target_io *tio = clone->end_io_data; 825 struct dm_rq_target_io *tio = clone->end_io_data;
831 struct mapped_device *md = tio->md; 826 struct mapped_device *md = tio->md;
832 struct request *rq = tio->orig; 827 struct request *rq = tio->orig;
@@ -848,7 +843,7 @@ static void dm_end_request(struct request *clone, int error)
848 843
849 blk_end_request_all(rq, error); 844 blk_end_request_all(rq, error);
850 845
851 rq_completed(md, 1); 846 rq_completed(md, rw, 1);
852} 847}
853 848
854/* 849/*
@@ -1541,12 +1536,13 @@ static void dm_request_fn(struct request_queue *q)
1541 struct mapped_device *md = q->queuedata; 1536 struct mapped_device *md = q->queuedata;
1542 struct dm_table *map = dm_get_table(md); 1537 struct dm_table *map = dm_get_table(md);
1543 struct dm_target *ti; 1538 struct dm_target *ti;
1544 struct request *rq; 1539 struct request *rq, *clone;
1545 1540
1546 /* 1541 /*
1547 * For suspend, check blk_queue_stopped() and don't increment 1542 * For suspend, check blk_queue_stopped() and increment
1548 * the number of in-flight I/Os after the queue is stopped 1543 * ->pending within a single queue_lock not to increment the
1549 * in dm_suspend(). 1544 * number of in-flight I/Os after the queue is stopped in
1545 * dm_suspend().
1550 */ 1546 */
1551 while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) { 1547 while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) {
1552 rq = blk_peek_request(q); 1548 rq = blk_peek_request(q);
@@ -1558,8 +1554,11 @@ static void dm_request_fn(struct request_queue *q)
1558 goto plug_and_out; 1554 goto plug_and_out;
1559 1555
1560 blk_start_request(rq); 1556 blk_start_request(rq);
1557 clone = rq->special;
1558 atomic_inc(&md->pending[rq_data_dir(clone)]);
1559
1561 spin_unlock(q->queue_lock); 1560 spin_unlock(q->queue_lock);
1562 map_request(ti, rq->special, md); 1561 map_request(ti, clone, md);
1563 spin_lock_irq(q->queue_lock); 1562 spin_lock_irq(q->queue_lock);
1564 } 1563 }
1565 1564
@@ -2071,8 +2070,6 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2071{ 2070{
2072 int r = 0; 2071 int r = 0;
2073 DECLARE_WAITQUEUE(wait, current); 2072 DECLARE_WAITQUEUE(wait, current);
2074 struct request_queue *q = md->queue;
2075 unsigned long flags;
2076 2073
2077 dm_unplug_all(md->queue); 2074 dm_unplug_all(md->queue);
2078 2075
@@ -2082,14 +2079,7 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2082 set_current_state(interruptible); 2079 set_current_state(interruptible);
2083 2080
2084 smp_mb(); 2081 smp_mb();
2085 if (dm_request_based(md)) { 2082 if (!md_in_flight(md))
2086 spin_lock_irqsave(q->queue_lock, flags);
2087 if (!queue_in_flight(q)) {
2088 spin_unlock_irqrestore(q->queue_lock, flags);
2089 break;
2090 }
2091 spin_unlock_irqrestore(q->queue_lock, flags);
2092 } else if (!md_in_flight(md))
2093 break; 2083 break;
2094 2084
2095 if (interruptible == TASK_INTERRUPTIBLE && 2085 if (interruptible == TASK_INTERRUPTIBLE &&