fsnotify: use an enum for group priority constants

And use meaningfull names for the constants.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240317184154.1200192-10-amir73il@gmail.com>

fs/notify/fanotify/fanotify_user.c

@@ -1516,13 +1516,13 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 	INIT_LIST_HEAD(&group->fanotify_data.access_list);
 	switch (class) {
 	case FAN_CLASS_NOTIF:
-		group->priority = FS_PRIO_0;
+		group->priority = FSNOTIFY_PRIO_NORMAL;
 		break;
 	case FAN_CLASS_CONTENT:
-		group->priority = FS_PRIO_1;
+		group->priority = FSNOTIFY_PRIO_CONTENT;
 		break;
 	case FAN_CLASS_PRE_CONTENT:
-		group->priority = FS_PRIO_2;
+		group->priority = FSNOTIFY_PRIO_PRE_CONTENT;
 		break;
 	default:
 		fd = -EINVAL;
@@ -1774,12 +1774,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		goto fput_and_out;
 
 	/*
-	 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF.  These are not
-	 * allowed to set permissions events.
+	 * Permission events require minimum priority FAN_CLASS_CONTENT.
 	 */
 	ret = -EINVAL;
 	if (mask & FANOTIFY_PERM_EVENTS &&
-	    group->priority == FS_PRIO_0)
+	    group->priority < FSNOTIFY_PRIO_CONTENT)
 		goto fput_and_out;
 
 	if (mask & FAN_FS_ERROR &&

include/linux/fsnotify_backend.h

@@ -176,6 +176,17 @@ struct fsnotify_event {
 	struct list_head list;
 };
 
+/*
+ * fsnotify group priorities.
+ * Events are sent in order from highest priority to lowest priority.
+ */
+enum fsnotify_group_prio {
+	FSNOTIFY_PRIO_NORMAL = 0,	/* normal notifiers, no permissions */
+	FSNOTIFY_PRIO_CONTENT,		/* fanotify permission events */
+	FSNOTIFY_PRIO_PRE_CONTENT,	/* fanotify pre-content events */
+	__FSNOTIFY_PRIO_NUM
+};
+
 /*
  * A group is a "thing" that wants to receive notification about filesystem
  * events.  The mask holds the subset of event types this group cares about.
@@ -201,14 +212,7 @@ struct fsnotify_group {
 	wait_queue_head_t notification_waitq;	/* read() on the notification file blocks on this waitq */
 	unsigned int q_len;			/* events on the queue */
 	unsigned int max_events;		/* maximum events allowed on the list */
-	/*
-	 * Valid fsnotify group priorities.  Events are send in order from highest
-	 * priority to lowest priority.  We default to the lowest priority.
-	 */
-	#define FS_PRIO_0	0 /* normal notifiers, no permissions */
-	#define FS_PRIO_1	1 /* fanotify content based access control */
-	#define FS_PRIO_2	2 /* fanotify pre-content access */
-	unsigned int priority;
+	enum fsnotify_group_prio priority;	/* priority for sending events */
 	bool shutdown;		/* group is being shut down, don't queue more events */
 
 #define FSNOTIFY_GROUP_USER	0x01 /* user allocated group */