Re: [PATCH v3] dm writecache: reject asynchronous pmem.

[Mikulas Patocka]

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@xxxxxxxxxxxxx/
> > Fixes: 6e84200c0a29 ("virtio-pmem: Add virtio pmem driver")
> > 
> > Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
> 
> Acked-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>

BTW, we should also add

Cc: stable@xxxxxxxxxxxxxxx	# 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
> > 
>