Re: [PATCH] xen/blkfront: When purging persistent grants, keep them in the buffer

From: Jens Axboe
Date: Thu Sep 27 2018 - 10:26:22 EST


On 9/27/18 1:12 AM, Juergen Gross wrote:
> On 22/09/18 21:55, Boris Ostrovsky wrote:
>> Commit a46b53672b2c ("xen/blkfront: cleanup stale persistent grants")
>> added support for purging persistent grants when they are not in use. As
>> part of the purge, the grants were removed from the grant buffer, This
>> eventually causes the buffer to become empty, with BUG_ON triggered in
>> get_free_grant(). This can be observed even on an idle system, within
>> 20-30 minutes.
>>
>> We should keep the grants in the buffer when purging, and only free the
>> grant ref.
>>
>> Fixes: a46b53672b2c ("xen/blkfront: cleanup stale persistent grants")
>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
>
> Reviewed-by: Juergen Gross <jgross@xxxxxxxx>

Since Konrad is out, I'm going to queue this up for 4.19.

--
Jens Axboe