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Subject: Re: [PATCH] xen/blkfront: When purging persistent grants, keep them
 in the buffer
To:     Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk
Cc:     xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
References: <20180922195549.27953-1-boris.ostrovsky@oracle.com>
From:   Juergen Gross <jgross@suse.com>
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Date:   Thu, 27 Sep 2018 09:12:56 +0200
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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@oracle.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen