Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 30 Jun 2020 12:14:26 -0400 (EDT)
From:   Mikulas Patocka <mpatocka@redhat.com>
To:     Michal Suchanek <msuchanek@suse.de>
cc:     linux-nvdimm@lists.01.org,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Jan Kara <jack@suse.cz>, Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com,
        Jakub Staron <jstaron@google.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Yuval Shaia <yuval.shaia@oracle.com>,
        Cornelia Huck <cohuck@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] dm writecache: reject asynchronous pmem.
In-Reply-To: <alpine.LRH.2.02.2006301210270.24082@file01.intranet.prod.int.rdu2.redhat.com>
Message-ID: <alpine.LRH.2.02.2006301213080.24082@file01.intranet.prod.int.rdu2.redhat.com>
References: <alpine.LRH.2.02.2006301101210.24028@file01.intranet.prod.int.rdu2.redhat.com> <20200630154924.3283-1-msuchanek@suse.de> <alpine.LRH.2.02.2006301210270.24082@file01.intranet.prod.int.rdu2.redhat.com>
User-Agent: Alpine 2.02 (LRH 1266 2009-07-14)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On Tue, 30 Jun 2020, Mikulas Patocka wrote:

> 
> 
> On Tue, 30 Jun 2020, Michal Suchanek wrote:
> 
> > The writecache driver does not handle asynchronous pmem. Reject it when
> > supplied as cache.
> > 
> > Link: https://lore.kernel.org/linux-nvdimm/87lfk5hahc.fsf@linux.ibm.com/
> > Fixes: 6e84200c0a29 ("virtio-pmem: Add virtio pmem driver")
> > 
> > Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> 
> Acked-by: Mikulas Patocka <mpatocka@redhat.com>

BTW, we should also add

Cc: stable@vger.kernel.org	# v5.3+

> > ---
> >  drivers/md/dm-writecache.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> > index 30505d70f423..5358894bb9fd 100644
> > --- a/drivers/md/dm-writecache.c
> > +++ b/drivers/md/dm-writecache.c
> > @@ -2266,6 +2266,12 @@ static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
> >  	}
> >  
> >  	if (WC_MODE_PMEM(wc)) {
> > +		if (!dax_synchronous(wc->ssd_dev->dax_dev)) {
> > +			r = -EOPNOTSUPP;
> > +			ti->error = "Asynchronous persistent memory not supported as pmem cache";
> > +			goto bad;
> > +		}
> > +
> >  		r = persistent_memory_claim(wc);
> >  		if (r) {
> >  			ti->error = "Unable to map persistent memory for cache";
> > -- 
> > 2.26.2
> > 
>