diff options
author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-11-17 14:32:57 +0100 |
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committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-11-17 14:32:57 +0100 |
commit | 3975797f3e72bd115c6ba80210c5fe65ebd9e14e (patch) | |
tree | f2fa6fe843d9d0d458f5455b3852960439572913 /block/blk-flush.c | |
parent | 78424c927cf194e2eb689b7871780e9182bd8c13 (diff) | |
parent | b7c0e47d98249c2ddf21ea197b651093c6aaee00 (diff) |
Merge remote-tracking branch 'airlied/drm-next' into drm-intel-next-queued
Tvrtko needs
commit b3c11ac267d461d3d597967164ff7278a919a39f
Author: Eric Engestrom <eric@engestrom.ch>
Date: Sat Nov 12 01:12:56 2016 +0000
drm: move allocation out of drm_get_format_name()
to be able to apply his patches without conflicts.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'block/blk-flush.c')
-rw-r--r-- | block/blk-flush.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c index 6a14b68b9135..3c882cbc7541 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -343,6 +343,34 @@ static void flush_data_end_io(struct request *rq, int error) struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); /* + * Updating q->in_flight[] here for making this tag usable + * early. Because in blk_queue_start_tag(), + * q->in_flight[BLK_RW_ASYNC] is used to limit async I/O and + * reserve tags for sync I/O. + * + * More importantly this way can avoid the following I/O + * deadlock: + * + * - suppose there are 40 fua requests comming to flush queue + * and queue depth is 31 + * - 30 rqs are scheduled then blk_queue_start_tag() can't alloc + * tag for async I/O any more + * - all the 30 rqs are completed before FLUSH_PENDING_TIMEOUT + * and flush_data_end_io() is called + * - the other rqs still can't go ahead if not updating + * q->in_flight[BLK_RW_ASYNC] here, meantime these rqs + * are held in flush data queue and make no progress of + * handling post flush rq + * - only after the post flush rq is handled, all these rqs + * can be completed + */ + + elv_completed_request(q, rq); + + /* for avoiding double accounting */ + rq->cmd_flags &= ~REQ_STARTED; + + /* * After populating an empty queue, kick it to avoid stall. Read * the comment in flush_end_io(). */ |