tree-wide: introduce mfree()

Pretty trivial helper which wraps free() but returns NULL, so we can
simplify this:
        free(foobar);
        foobar = NULL;
to this:
        foobar = mfree(foobar);

2 files changed, 5 insertions, 10 deletions

diff --git a/src/udev/udev-builtin-path_id.c b/src/udev/udev-builtin-path_id.c
index 4ca0a69d7d..aa5cda6fe7 100644
--- a/src/udev/udev-builtin-path_id.c
+++ b/src/udev/udev-builtin-path_id.c
@@ -674,20 +674,16 @@ static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool
          * might produce conflicting IDs if the parent does not provide a
          * unique and predictable name.
          */
-        if (!supported_parent) {
-                free(path);
-                path = NULL;
-        }
+        if (!supported_parent)
+                path = mfree(path);
 
         /*
          * Do not return block devices without a well-known transport. Some
          * devices do not expose their buses and do not provide a unique
          * and predictable name that way.
          */
-        if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport) {
-                free(path);
-                path = NULL;
-        }
+        if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport)
+                path = mfree(path);
 
 out:
         if (path != NULL) {
diff --git a/src/udev/udev-rules.c b/src/udev/udev-rules.c
index bbb9f97226..368da9b1ae 100644
--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -2589,8 +2589,7 @@ int udev_rules_apply_static_dev_perms(struct udev_rules *rules) {
                         uid = 0;
                         gid = 0;
                         mode = 0;
-                        strv_free(tags);
-                        tags = NULL;
+                        tags = strv_free(tags);
                         break;
                 case TK_A_OWNER_ID:
                         uid = cur->key.uid;