diff options
Diffstat (limited to 'block/blk-flush.c')
| -rw-r--r-- | block/blk-flush.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c index d308def812db..3c882cbc7541 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -232,7 +232,7 @@ static void flush_end_io(struct request *flush_rq, int error) /* release the tag's ownership to the req cloned from */ spin_lock_irqsave(&fq->mq_flush_lock, flags); - hctx = q->mq_ops->map_queue(q, flush_rq->mq_ctx->cpu); + hctx = blk_mq_map_queue(q, flush_rq->mq_ctx->cpu); blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq); flush_rq->tag = -1; } @@ -325,7 +325,7 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq) flush_rq->tag = first_rq->tag; fq->orig_rq = first_rq; - hctx = q->mq_ops->map_queue(q, first_rq->mq_ctx->cpu); + hctx = blk_mq_map_queue(q, first_rq->mq_ctx->cpu); blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq); } @@ -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(). */ @@ -358,7 +386,7 @@ static void mq_flush_data_end_io(struct request *rq, int error) unsigned long flags; struct blk_flush_queue *fq = blk_get_flush_queue(q, ctx); - hctx = q->mq_ops->map_queue(q, ctx->cpu); + hctx = blk_mq_map_queue(q, ctx->cpu); /* * After populating an empty queue, kick it to avoid stall. Read |
