On 22/05/2023 03:12, Tian Lan wrote:
From: Tian Lan <tian.lan@xxxxxxxxxxxx>
If multiple CPUs are sharing the same hardware queue, it can
cause leak in the active queue counter tracking when __blk_mq_tag_busy()
is executed simultaneously.
Fixes: ee78ec1077d3 ("blk-mq: blk_mq_tag_busy is no need to return a value")
Signed-off-by: Tian Lan <tian.lan@xxxxxxxxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq-tag.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index d6af9d431dc6..0db6c31d3f4a 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -42,13 +42,13 @@ void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
if (blk_mq_is_shared_tags(hctx->flags)) {
struct request_queue *q = hctx->queue;
- if (test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
+ if (test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags) ||
+ test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
How about add a small comment why we have the test_bit()? It seems to be
asked every so often, like:
https://lore.kernel.org/linux-block/6e2db454-b2f7-16a1-acc6-999ee09fdf10@xxxxxxx/#t
return;
- set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags);
} else {
- if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+ if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) ||
+ test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return;
- set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state);
}
users = atomic_inc_return(&hctx->tags->active_queues);
