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authorMing Lei <ming.lei@redhat.com>2023-05-18 07:30:59 +0200
committerJens Axboe <axboe@kernel.dk>2023-05-18 19:40:09 -0600
commitd97217e7f024bbe9aa62aea070771234c2879358 (patch)
treecfcb145de4b2ee8091c8e5b136072c814472d76a /block
parentd5fb8726f1dea70543a93ab1d7332857f157b7f3 (diff)
blk-mq: don't queue plugged passthrough requests into scheduler
Passthrough requests should never be queued to the I/O scheduler, as scheduling these opaque requests doesn't make sense, and I/O schedulers might require req->bio to be always valid. We never let passthrough requests insert into the scheduler before commit 1c2d2fff6dc0 ("block: wire-up support for passthrough plugging"), restore this behavior even for passthrough requests issued under a plug. [hch: use blk_mq_insert_requests for passthrough requests, fix up the commit message and comments] Reported-by: Guangwu Zhang <guazhang@redhat.com> Closes: https://lore.kernel.org/linux-block/CAGS2=YosaYaUTEMU3uaf+y=8MqSrhL7sYsJn8EwbaM=76p_4Qg@mail.gmail.com/ Investigated-by: Yu Kuai <yukuai1@huaweicloud.com> Fixes: 1c2d2fff6dc0 ("block: wire-up support for passthrough plugging") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230518053101.760632-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f6dad0886a2f..8b7e4daaa5b7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2711,6 +2711,7 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
struct request *requeue_list = NULL;
struct request **requeue_lastp = &requeue_list;
unsigned int depth = 0;
+ bool is_passthrough = false;
LIST_HEAD(list);
do {
@@ -2719,7 +2720,9 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
if (!this_hctx) {
this_hctx = rq->mq_hctx;
this_ctx = rq->mq_ctx;
- } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx) {
+ is_passthrough = blk_rq_is_passthrough(rq);
+ } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx ||
+ is_passthrough != blk_rq_is_passthrough(rq)) {
rq_list_add_tail(&requeue_lastp, rq);
continue;
}
@@ -2731,7 +2734,8 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
trace_block_unplug(this_hctx->queue, depth, !from_sched);
percpu_ref_get(&this_hctx->queue->q_usage_counter);
- if (this_hctx->queue->elevator) {
+ /* passthrough requests should never be issued to the I/O scheduler */
+ if (this_hctx->queue->elevator && !is_passthrough) {
this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
&list, 0);
blk_mq_run_hw_queue(this_hctx, from_sched);