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

[Mikulas Patocka]

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>

> ---
>  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
>