fsnotify: Add wrapper around fsnotify_add_event

fsnotify_add_event is growing in number of parameters, which in most
case are just passed a NULL pointer.  So, split out a new
fsnotify_insert_event function to clean things up for users who don't
need an insert hook.

Link: https://lore.kernel.org/r/20211025192746.66445-10-krisman@collabora.com
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/fanotify/fanotify.c

@@ -781,8 +781,8 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
 	}
 
 	fsn_event = &event->fse;
-	ret = fsnotify_add_event(group, fsn_event, fanotify_merge,
+	ret = fsnotify_insert_event(group, fsn_event, fanotify_merge,
-				 fanotify_insert_event);
+				    fanotify_insert_event);
 	if (ret) {
 		/* Permission events shouldn't be merged */
 		BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS);

fs/notify/inotify/inotify_fsnotify.c

@@ -116,7 +116,7 @@ int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, u32 mask,
 	if (len)
 		strcpy(event->name, name->name);
 
-	ret = fsnotify_add_event(group, fsn_event, inotify_merge, NULL);
+	ret = fsnotify_add_event(group, fsn_event, inotify_merge);
 	if (ret) {
 		/* Our event wasn't used in the end. Free it. */
 		fsnotify_destroy_event(group, fsn_event);

fs/notify/notification.c

@@ -78,12 +78,12 @@ void fsnotify_destroy_event(struct fsnotify_group *group,
  * 2 if the event was not queued - either the queue of events has overflown
  *   or the group is shutting down.
  */
-int fsnotify_add_event(struct fsnotify_group *group,
+int fsnotify_insert_event(struct fsnotify_group *group,
-		       struct fsnotify_event *event,
+			  struct fsnotify_event *event,
-		       int (*merge)(struct fsnotify_group *,
+			  int (*merge)(struct fsnotify_group *,
-				    struct fsnotify_event *),
+				       struct fsnotify_event *),
-		       void (*insert)(struct fsnotify_group *,
+			  void (*insert)(struct fsnotify_group *,
-				      struct fsnotify_event *))
+					 struct fsnotify_event *))
 {
 	int ret = 0;
 	struct list_head *list = &group->notification_list;

include/linux/fsnotify_backend.h

@@ -498,16 +498,25 @@ extern int fsnotify_fasync(int fd, struct file *file, int on);
 extern void fsnotify_destroy_event(struct fsnotify_group *group,
 				   struct fsnotify_event *event);
 /* attach the event to the group notification queue */
-extern int fsnotify_add_event(struct fsnotify_group *group,
+extern int fsnotify_insert_event(struct fsnotify_group *group,
-			      struct fsnotify_event *event,
+				 struct fsnotify_event *event,
-			      int (*merge)(struct fsnotify_group *,
+				 int (*merge)(struct fsnotify_group *,
-					   struct fsnotify_event *),
+					      struct fsnotify_event *),
-			      void (*insert)(struct fsnotify_group *,
+				 void (*insert)(struct fsnotify_group *,
-					     struct fsnotify_event *));
+						struct fsnotify_event *));
+
+static inline int fsnotify_add_event(struct fsnotify_group *group,
+				     struct fsnotify_event *event,
+				     int (*merge)(struct fsnotify_group *,
+						  struct fsnotify_event *))
+{
+	return fsnotify_insert_event(group, event, merge, NULL);
+}
+
 /* Queue overflow event to a notification group */
 static inline void fsnotify_queue_overflow(struct fsnotify_group *group)
 {
-	fsnotify_add_event(group, group->overflow_event, NULL, NULL);
+	fsnotify_add_event(group, group->overflow_event, NULL);
 }
 
 static inline bool fsnotify_is_overflow_event(u32 mask)