Fix match_prepath()

Incorrect return value for shares not using the prefix path means that
we will never match superblocks for these shares.

Fixes: commit c1d8b24d1819 ("Compare prepaths when comparing superblocks")
Cc: stable@vger.kernel.org
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/connect.c

@@ -2912,16 +2912,14 @@ match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
 {
 	struct cifs_sb_info *old = CIFS_SB(sb);
 	struct cifs_sb_info *new = mnt_data->cifs_sb;
+	bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
+	bool new_set = new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
 
-	if (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) {
-		if (!(new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH))
-			return 0;
-		/* The prepath should be null terminated strings */
-		if (strcmp(new->prepath, old->prepath))
-			return 0;
-
+	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
 		return 1;
-	}
+	else if (!old_set && !new_set)
+		return 1;
+
 	return 0;
 }