* [dm-devel] [PATCH] dm-rq: don't queue request during suspend
@ 2021-09-23 9:11 Ming Lei
2021-10-06 14:15 ` [dm-devel] " Mike Snitzer
0 siblings, 1 reply; 3+ messages in thread
From: Ming Lei @ 2021-09-23 9:11 UTC (permalink / raw)
To: Mike Snitzer, dm-devel; +Cc: Ming Lei
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
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [dm-devel] dm-rq: don't queue request during suspend
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
2021-10-07 7:06 ` Ming Lei
0 siblings, 1 reply; 3+ messages in thread
From: Mike Snitzer @ 2021-10-06 14:15 UTC (permalink / raw)
To: Ming Lei; +Cc: dm-devel
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dm-devel] dm-rq: don't queue request during suspend
2021-10-06 14:15 ` [dm-devel] " Mike Snitzer
@ 2021-10-07 7:06 ` Ming Lei
0 siblings, 0 replies; 3+ messages in thread
From: Ming Lei @ 2021-10-07 7:06 UTC (permalink / raw)
To: Mike Snitzer; +Cc: dm-devel
On Wed, Oct 06, 2021 at 10:15:58AM -0400, Mike Snitzer wrote:
> 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.
Hello Mike,
I understand the device shouldn't be suspended after the test given
it is just like the following two tasks running contiguously in the
test:
1) task1
- suspend device mapper
- resume device mapper
2) task2
- updating nr_requests of the device mapper
BTW, it is reported as RH BZ1891486 in which it is easily reproduced,
however, seems device suspended isn't observed.
thanks,
Ming
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-10-07 7:28 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-23 9:11 [dm-devel] [PATCH] dm-rq: don't queue request during suspend Ming Lei
2021-10-06 14:15 ` [dm-devel] " Mike Snitzer
2021-10-07 7:06 ` Ming Lei
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.