nfsd: Avoid some useless tests

memdup_user() can't return NULL, so there is no point for checking for it.

Simplify some tests accordingly.
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4recover.c

@@ -807,7 +807,7 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
 			if (get_user(namelen, &ci->cc_name.cn_len))
 				return -EFAULT;
 			name.data = memdup_user(&ci->cc_name.cn_id, namelen);
-			if (IS_ERR_OR_NULL(name.data))
+			if (IS_ERR(name.data))
 				return -EFAULT;
 			name.len = namelen;
 			get_user(princhashlen, &ci->cc_princhash.cp_len);
@@ -815,7 +815,7 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
 				princhash.data = memdup_user(
 						&ci->cc_princhash.cp_data,
 						princhashlen);
-				if (IS_ERR_OR_NULL(princhash.data)) {
+				if (IS_ERR(princhash.data)) {
 					kfree(name.data);
 					return -EFAULT;
 				}
@@ -829,7 +829,7 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
 			if (get_user(namelen, &cnm->cn_len))
 				return -EFAULT;
 			name.data = memdup_user(&cnm->cn_id, namelen);
-			if (IS_ERR_OR_NULL(name.data))
+			if (IS_ERR(name.data))
 				return -EFAULT;
 			name.len = namelen;
 		}