audit: do not get and put just to free a watch

deleting audit watch rules is not currently done under audit_filter_mutex.
It was done this way because we could not hold the mutex during inotify
manipulation.  Since we are using fsnotify we don't need to do the extra
get/put pair nor do we need the private list on which to store the parents
while they are about to be freed.
Signed-off-by: Eric Paris <eparis@redhat.com>

kernel/audit.h

@@ -108,8 +108,7 @@ extern void audit_put_watch(struct audit_watch *watch);
 extern void audit_get_watch(struct audit_watch *watch);
 extern int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op);
 extern int audit_add_watch(struct audit_krule *krule, struct list_head **list);
-extern void audit_remove_watch_rule(struct audit_krule *krule, struct list_head *list);
-extern void audit_watch_inotify_unregister(struct list_head *in_list);
+extern void audit_remove_watch_rule(struct audit_krule *krule);
 extern char *audit_watch_path(struct audit_watch *watch);
 extern int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev);
 extern struct audit_entry *audit_dupe_rule(struct audit_krule *old);

kernel/audit_watch.c

@@ -55,7 +55,6 @@ struct audit_watch {
 };
 
 struct audit_parent {
-	struct list_head	ilist;	/* tmp list used to free parents */
 	struct list_head	watches; /* anchor for audit_watch->wlist */
 	struct fsnotify_mark_entry mark; /* fsnotify mark on the inode */
 };
@@ -356,20 +355,6 @@ static void audit_remove_parent_watches(struct audit_parent *parent)
 	fsnotify_destroy_mark_by_entry(&parent->mark);
 }
 
-/* Unregister inotify watches for parents on in_list.
- * Generates an FS_IGNORED event. */
-void audit_watch_inotify_unregister(struct list_head *in_list)
-{
-	struct audit_parent *p, *n;
-
-	list_for_each_entry_safe(p, n, in_list, ilist) {
-		list_del(&p->ilist);
-		fsnotify_destroy_mark_by_entry(&p->mark);
-		/* matches the get in audit_remove_watch_rule() */
-		audit_put_parent(p);
-	}
-}
-
 /* Get path information necessary for adding watches. */
 static int audit_get_nd(char *path, struct nameidata **ndp, struct nameidata **ndw)
 {
@@ -502,7 +487,7 @@ int audit_add_watch(struct audit_krule *krule, struct list_head **list)
 
 }
 
-void audit_remove_watch_rule(struct audit_krule *krule, struct list_head *list)
+void audit_remove_watch_rule(struct audit_krule *krule)
 {
 	struct audit_watch *watch = krule->watch;
 	struct audit_parent *parent = watch->parent;
@@ -513,15 +498,9 @@ void audit_remove_watch_rule(struct audit_krule *krule, struct list_head *list)
 		audit_remove_watch(watch);
 
 		if (list_empty(&parent->watches)) {
-			/* Put parent on the un-registration list.
-			 * Grab a reference before releasing
-			 * audit_filter_mutex, to be released in
-			 * audit_watch_inotify_unregister().
-			 * If filesystem is going away, just leave
-			 * the sucker alone, eviction will take
-			 * care of it. */
 			audit_get_parent(parent);
-			list_add(&parent->ilist, list);
+			fsnotify_destroy_mark_by_entry(&parent->mark);
+			audit_put_parent(parent);
 		}
 	}
 }

kernel/auditfilter.c

@@ -945,7 +945,6 @@ static inline int audit_del_rule(struct audit_entry *entry)
 	struct audit_watch *watch = entry->rule.watch;
 	struct audit_tree *tree = entry->rule.tree;
 	struct list_head *list;
-	LIST_HEAD(inotify_unregister_list);
 	int ret = 0;
 #ifdef CONFIG_AUDITSYSCALL
 	int dont_count = 0;
@@ -965,7 +964,7 @@ static inline int audit_del_rule(struct audit_entry *entry)
 	}
 
 	if (e->rule.watch)
-		audit_remove_watch_rule(&e->rule, &inotify_unregister_list);
+		audit_remove_watch_rule(&e->rule);
 
 	if (e->rule.tree)
 		audit_remove_tree_rule(&e->rule);
@@ -983,9 +982,6 @@ static inline int audit_del_rule(struct audit_entry *entry)
 #endif
 	mutex_unlock(&audit_filter_mutex);
 
-	if (!list_empty(&inotify_unregister_list))
-		audit_watch_inotify_unregister(&inotify_unregister_list);
-
 out:
 	if (watch)
 		audit_put_watch(watch); /* match initial get */