Re: dm-mq and end_clone_request()

[Mike Snitzer <snitzer@redhat.com>]

On Mon, Jul 25 2016 at  9:16pm -0400,
Mike Snitzer <snitzer@redhat.com> wrote:
 
> Hi Bart,
> 
> Please try this patch to see if it fixes your issue, thanks.
> 
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 52baf8a..287caa7 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -433,10 +433,17 @@ failed:
>   */
>  static int must_push_back(struct multipath *m)
>  {
> -	return (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) ||
> -		((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) !=
> -		  test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) &&
> -		 dm_noflush_suspending(m->ti)));
> +	bool r;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&m->lock, flags);
> +	r = (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) ||
> +	     ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) !=
> +	       test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) &&
> +	      dm_noflush_suspending(m->ti)));
> +	spin_unlock_irqrestore(&m->lock, flags);
> +
> +	return r;
>  }
>  
>  /*

In addition to the above patch, please apply this patch and retest your
4.7 kernel:

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 287caa7..16583c1 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1416,12 +1416,14 @@ static void multipath_postsuspend(struct dm_target *ti)
 static void multipath_resume(struct dm_target *ti)
 {
 	struct multipath *m = ti->private;
+	unsigned long flags;
 
+	spin_lock_irqsave(&m->lock, flags);
 	if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags))
 		set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
 	else
 		clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
-	smp_mb__after_atomic();
+	spin_unlock_irqrestore(&m->lock, flags);
 }
 
 /*