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authorMing Lei <ming.lei@redhat.com>2022-06-16 04:44:00 +0300
committerJens Axboe <axboe@kernel.dk>2022-06-16 23:45:15 +0300
commit4d337cebcb1c27d9b48c48b9a98e939d4552d584 (patch)
tree145de66b189943b28e6b089d4345459a7d22d2c6 /block/blk-mq.c
parent5fd7a84a09e640016fe106dd3e992f5210e23dc7 (diff)
downloadlinux-4d337cebcb1c27d9b48c48b9a98e939d4552d584.tar.xz
blk-mq: avoid to touch q->elevator without any protection
q->elevator is referred in blk_mq_has_sqsched() without any protection, no .q_usage_counter is held, no queue srcu and rcu read lock is held, so potential use-after-free may be triggered. Fix the issue by adding one queue flag for checking if the elevator uses single queue style dispatch. Meantime the elevator feature flag of ELEVATOR_F_MQ_AWARE isn't needed any more. Cc: Jan Kara <jack@suse.cz> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220616014401.817001-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c18
1 files changed, 2 insertions, 16 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index c13d03b2e17c..4cdb08a70912 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2143,20 +2143,6 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
EXPORT_SYMBOL(blk_mq_run_hw_queue);
/*
- * Is the request queue handled by an IO scheduler that does not respect
- * hardware queues when dispatching?
- */
-static bool blk_mq_has_sqsched(struct request_queue *q)
-{
- struct elevator_queue *e = q->elevator;
-
- if (e && e->type->ops.dispatch_request &&
- !(e->type->elevator_features & ELEVATOR_F_MQ_AWARE))
- return true;
- return false;
-}
-
-/*
* Return prefered queue to dispatch from (if any) for non-mq aware IO
* scheduler.
*/
@@ -2188,7 +2174,7 @@ void blk_mq_run_hw_queues(struct request_queue *q, bool async)
unsigned long i;
sq_hctx = NULL;
- if (blk_mq_has_sqsched(q))
+ if (blk_queue_sq_sched(q))
sq_hctx = blk_mq_get_sq_hctx(q);
queue_for_each_hw_ctx(q, hctx, i) {
if (blk_mq_hctx_stopped(hctx))
@@ -2216,7 +2202,7 @@ void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
unsigned long i;
sq_hctx = NULL;
- if (blk_mq_has_sqsched(q))
+ if (blk_queue_sq_sched(q))
sq_hctx = blk_mq_get_sq_hctx(q);
queue_for_each_hw_ctx(q, hctx, i) {
if (blk_mq_hctx_stopped(hctx))