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authorBart Van Assche <bvanassche@acm.org>2021-05-13 10:15:29 -0700
committerJens Axboe <axboe@kernel.dk>2021-05-14 08:59:31 -0600
commit630ef623ed26c18a457cdc070cf24014e50129c2 (patch)
tree56a81c02b4012c577280c5728c7e683bb3abdf4f /block
parent03f26d8f11403295de445b6e4e0e57ac57755791 (diff)
blk-mq: Swap two calls in blk_mq_exit_queue()
If a tag set is shared across request queues (e.g. SCSI LUNs) then the block layer core keeps track of the number of active request queues in tags->active_queues. blk_mq_tag_busy() and blk_mq_tag_idle() update that atomic counter if the hctx flag BLK_MQ_F_TAG_QUEUE_SHARED is set. Make sure that blk_mq_exit_queue() calls blk_mq_tag_idle() before that flag is cleared by blk_mq_del_queue_tag_set(). Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Fixes: 0d2602ca30e4 ("blk-mq: improve support for shared tags maps") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210513171529.7977-1-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 28ef0248efba..c86c01bfecdb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3286,10 +3286,12 @@ EXPORT_SYMBOL(blk_mq_init_allocated_queue);
/* tags can _not_ be used after returning from blk_mq_exit_queue */
void blk_mq_exit_queue(struct request_queue *q)
{
- struct blk_mq_tag_set *set = q->tag_set;
+ struct blk_mq_tag_set *set = q->tag_set;
- blk_mq_del_queue_tag_set(q);
+ /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
+ /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
+ blk_mq_del_queue_tag_set(q);
}
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)

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