md/dm-writecache: Don't request pointer dummy_addr when not required

Function persistent_memory_claim doesn't need to get local pointer
dummy_addr from direct_access. Using NULL instead of having to pass
in a useless local pointer that caller then just throw away.

Suggested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 5961c7794ef37008f7a10f521517aded086f20f3..1839236a0f8150b4db50be5f8178895f0d3dc3b0 100644 (file)
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -267,9 +267,8 @@ static int persistent_memory_claim(struct dm_writecache *wc)
                i = 0;
                do {
                        long daa;
-                       void *dummy_addr;
                        daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
-                                               &dummy_addr, &pfn);
+                                               NULL, &pfn);
                        if (daa <= 0) {
                                r = daa ? daa : -EINVAL;
                                goto err3;