From: Michal Suchanek <msuchanek@xxxxxxx> commit a46624580376a3a0beb218d94cbc7f258696e29f upstream. DM writecache 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> Cc: stable@xxxxxxxxxxxxxxx # 5.3+ Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-writecache.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -2104,6 +2104,12 @@ invalid_optional: } 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";
