Merge tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block

Pull core block updates from Jens Axboe:
 "Good amount of cleanups and tech debt removals in here, and as a
  result, the diffstat shows a nice net reduction in code.

   - Softirq completion cleanups (Christoph)

   - Stop using ->queuedata (Christoph)

   - Cleanup bd claiming (Christoph)

   - Use check_events, moving away from the legacy media change
     (Christoph)

   - Use inode i_blkbits consistently (Christoph)

   - Remove old unused writeback congestion bits (Christoph)

   - Cleanup/unify submission path (Christoph)

   - Use bio_uninit consistently, instead of bio_disassociate_blkg
     (Christoph)

   - sbitmap cleared bits handling (John)

   - Request merging blktrace event addition (Jan)

   - sysfs add/remove race fixes (Luis)

   - blk-mq tag fixes/optimizations (Ming)

   - Duplicate words in comments (Randy)

   - Flush deferral cleanup (Yufen)

   - IO context locking/retry fixes (John)

   - struct_size() usage (Gustavo)

   - blk-iocost fixes (Chengming)

   - blk-cgroup IO stats fixes (Boris)

   - Various little fixes"

* tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block: (135 commits)
  block: blk-timeout: delete duplicated word
  block: blk-mq-sched: delete duplicated word
  block: blk-mq: delete duplicated word
  block: genhd: delete duplicated words
  block: elevator: delete duplicated word and fix typos
  block: bio: delete duplicated words
  block: bfq-iosched: fix duplicated word
  iocost_monitor: start from the oldest usage index
  iocost: Fix check condition of iocg abs_vdebt
  block: Remove callback typedefs for blk_mq_ops
  block: Use non _rcu version of list functions for tag_set_list
  blk-cgroup: show global disk stats in root cgroup io.stat
  blk-cgroup: make iostat functions visible to stat printing
  block: improve discard bio alignment in __blkdev_issue_discard()
  block: change REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL to be odd numbers
  block: defer flush request no matter whether we have elevator
  block: make blk_timeout_init() static
  block: remove retry loop in ioc_release_fn()
  block: remove unnecessary ioc nested locking
  block: integrate bd_start_claiming into __blkdev_get
  ...

1 files changed, 6 insertions, 17 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 15ae0155ec07..6e1543c10493 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -219,7 +219,6 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 	struct request *rq, *n;
 	unsigned long flags = 0;
 	struct blk_flush_queue *fq = blk_get_flush_queue(q, flush_rq->mq_ctx);
-	struct blk_mq_hw_ctx *hctx;
 
 	blk_account_io_flush(flush_rq);
 
@@ -235,13 +234,11 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 	if (fq->rq_status != BLK_STS_OK)
 		error = fq->rq_status;
 
-	hctx = flush_rq->mq_hctx;
 	if (!q->elevator) {
-		blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq);
-		flush_rq->tag = -1;
+		flush_rq->tag = BLK_MQ_NO_TAG;
 	} else {
 		blk_mq_put_driver_tag(flush_rq);
-		flush_rq->internal_tag = -1;
+		flush_rq->internal_tag = BLK_MQ_NO_TAG;
 	}
 
 	running = &fq->flush_queue[fq->flush_running_idx];
@@ -286,13 +283,8 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
 	if (fq->flush_pending_idx != fq->flush_running_idx || list_empty(pending))
 		return;
 
-	/* C2 and C3
-	 *
-	 * For blk-mq + scheduling, we can risk having all driver tags
-	 * assigned to empty flushes, and we deadlock if we are expecting
-	 * other requests to make progress. Don't defer for that case.
-	 */
-	if (!list_empty(&fq->flush_data_in_flight) && q->elevator &&
+	/* C2 and C3 */
+	if (!list_empty(&fq->flush_data_in_flight) &&
 	    time_before(jiffies,
 			fq->flush_pending_since + FLUSH_PENDING_TIMEOUT))
 		return;
@@ -316,13 +308,10 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
 	flush_rq->mq_ctx = first_rq->mq_ctx;
 	flush_rq->mq_hctx = first_rq->mq_hctx;
 
-	if (!q->elevator) {
-		fq->orig_rq = first_rq;
+	if (!q->elevator)
 		flush_rq->tag = first_rq->tag;
-		blk_mq_tag_set_rq(flush_rq->mq_hctx, first_rq->tag, flush_rq);
-	} else {
+	else
 		flush_rq->internal_tag = first_rq->internal_tag;
-	}
 
 	flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;
 	flush_rq->cmd_flags |= (flags & REQ_DRV) | (flags & REQ_FAILFAST_MASK);