Re: [PATCH 09/98] blk-mq: end the request if getting a keyslot fails

[Christoph Hellwig <hch@infradead.org>]

Adding Eric for the blk-crypto code.

On Wed, Oct 28, 2026 at 10:41:12AM -0600, Jens Axboe wrote:
> From: Josef Bacik <josef@toxicpanda.com>
> 
> When blk_crypto_rq_get_keyslot() fails, blk_mq_submit_bio() ends the bio
> by hand and frees the request. By then blk_mq_bio_to_request() has done
> the IO accounting, which blk_mq_free_request() doesn't undo, so the
> in_flight counter never drops and iostat shows a device that is 100%
> busy. If the bio went through zone write plugging the zone stays plugged
> as well, and every later write to it waits forever.
> 
> Use blk_mq_end_request() like the dispatch path does for a request the
> driver rejected, after marking it for zone write plugging.
> 
> Fixes: a892c8d52c02 ("block: Inline encryption support for blk-mq")
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  block/blk-mq.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 7400f678258e..c91306f8156f 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -3195,8 +3195,9 @@ void blk_mq_submit_bio(struct bio *bio)
>  
>  	ret = blk_crypto_rq_get_keyslot(rq);
>  	if (ret != BLK_STS_OK) {
> -		bio_endio_status(bio, ret);
> -		blk_mq_free_request(rq);
> +		if (bio_zone_write_plugging(bio))
> +			blk_zone_write_plug_init_request(rq);
> +		blk_mq_end_request(rq, ret);

If blk_mq_end_request does the right thing (it looks like that to
me, but I'd rather rely on Eric and Jens for that), we should
reorder the blk_crypto_rq_get_keyslot and
blk_zone_write_plug_init_request calls so that the extra copy
of the blk_zone_write_plug_init_request call is not needed.