From: Mike Snitzer <snitzer@redhat.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: dm-devel@redhat.com
Subject: Re: [dm-devel] dm-rq: don't queue request during suspend
Date: Wed, 6 Oct 2021 10:15:58 -0400 [thread overview]
Message-ID: <YV2vnlKScVXYvQMo@redhat.com> (raw)
In-Reply-To: <20210923091131.1463013-1-ming.lei@redhat.com>
On Thu, Sep 23 2021 at 5:11P -0400,
Ming Lei <ming.lei@redhat.com> wrote:
> DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue.
>
> But blk-mq's unquiesce may come from outside events, such as elevator
> switch, updating nr_requests or others, and request may come during
> suspend, so simply ask for blk-mq to requeue it.
>
> Fixes one kernel panic issue when running updating nr_requests and
> dm-mpath suspend/resume stress test.
>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
> drivers/md/dm-rq.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
> index 5b95eea517d1..a896dea9750e 100644
> --- a/drivers/md/dm-rq.c
> +++ b/drivers/md/dm-rq.c
> @@ -490,6 +490,14 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
> struct mapped_device *md = tio->md;
> struct dm_target *ti = md->immutable_target;
>
> + /*
> + * blk-mq's unquiesce may come from outside events, such as
> + * elevator switch, updating nr_requests or others, and request may
> + * come during suspend, so simply ask for blk-mq to requeue it.
> + */
> + if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)))
> + return BLK_STS_RESOURCE;
> +
> if (unlikely(!ti)) {
> int srcu_idx;
> struct dm_table *map = dm_get_live_table(md, &srcu_idx);
> --
> 2.31.1
>
Hey Ming,
I've marked this for stable@ and queued this up. BUT this test is
racey, could easily be that device gets suspended just after your
test.
Mike
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2021-10-06 14:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 9:11 [dm-devel] [PATCH] dm-rq: don't queue request during suspend Ming Lei
2021-10-06 14:15 ` Mike Snitzer [this message]
2021-10-07 7:06 ` [dm-devel] " Ming Lei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YV2vnlKScVXYvQMo@redhat.com \
--to=snitzer@redhat.com \
--cc=dm-devel@redhat.com \
--cc=ming.lei@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).