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authorMing Lei <ming.lei@redhat.com>2022-05-22 20:23:50 +0800
committerJens Axboe <axboe@kernel.dk>2022-05-23 06:28:28 -0600
commit5d05426e2d5fd7df8afc866b78c36b37b00188b7 (patch)
tree1d606e3f04b70a0c8a96c4e3bb6f43bb2e6473a9
parent2aaf516084184e4e6f80da01b2b3ed882fd20a79 (diff)
blk-mq: don't touch ->tagset in blk_mq_get_sq_hctx
blk_mq_run_hw_queues() could be run when there isn't queued request and after queue is cleaned up, at that time tagset is freed, because tagset lifetime is covered by driver, and often freed after blk_cleanup_queue() returns. So don't touch ->tagset for figuring out current default hctx by the mapping built in request queue, so use-after-free on tagset can be avoided. Meantime this way should be fast than retrieving mapping from tagset. Cc: "yukuai (C)" <yukuai3@huawei.com> Cc: Jan Kara <jack@suse.cz> Fixes: b6e68ee82585 ("blk-mq: Improve performance of non-mq IO schedulers with multiple HW queues") Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220522122350.743103-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk-mq.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9ef2d3284752..174fe8051d60 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2130,8 +2130,7 @@ static bool blk_mq_has_sqsched(struct request_queue *q)
*/
static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
{
- struct blk_mq_hw_ctx *hctx;
-
+ struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
/*
* If the IO scheduler does not respect hardware queues when
* dispatching, we just don't bother with multiple HW queues and
@@ -2139,8 +2138,8 @@ static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
* just causes lock contention inside the scheduler and pointless cache
* bouncing.
*/
- hctx = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT,
- raw_smp_processor_id());
+ struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, 0, ctx);
+
if (!blk_mq_hctx_stopped(hctx))
return hctx;
return NULL;