[PATCH v7 5/5] dm-crypt: Fix lost ioprio when queuing write bios

From: Hongyu Jin
Date: Thu Dec 21 2023 - 05:33:36 EST


From: Hongyu Jin <hongyu.jin@xxxxxxxxxx>

Since dm-crypt queues writes to a different kernel thread (workqueue),
the bios will dispatch from tasks with different io_context->ioprio
settings and blkcg than the submitting task, thus giving incorrect
ioprio to the io scheduler.

Get the original io priority setting via struct dm_crypt_io::base_bio
and set this priority to the bio for write.

Link: https://lore.kernel.org/dm-devel/alpine.LRH.2.11.1612141049250.13402@xxxxxxxxxxxxxxxxx

Signed-off-by: Hongyu Jin <hongyu.jin@xxxxxxxxxx>
---
drivers/md/dm-crypt.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 2ae8560b6a14..ba6e794f7871 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1683,6 +1683,7 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned int size)
GFP_NOIO, &cc->bs);
clone->bi_private = io;
clone->bi_end_io = crypt_endio;
+ clone->bi_ioprio = io->base_bio->bi_ioprio;

remaining_size = size;

--
2.34.1