1 files changed, 45 insertions, 313 deletions

diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 7b51b05f160c..1e58402171a5 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -48,15 +48,6 @@
 #include <linux/fsnotify_backend.h>
 #include "fsnotify.h"
 
-static struct kmem_cache *fsnotify_event_cachep;
-static struct kmem_cache *fsnotify_event_holder_cachep;
-/*
- * This is a magic event we send when the q is too full.  Since it doesn't
- * hold real event information we just keep one system wide and use it any time
- * it is needed.  It's refcnt is set 1 at kernel init time and will never
- * get set to 0 so it will never get 'freed'
- */
-static struct fsnotify_event *q_overflow_event;
 static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0);
 
 /**
@@ -76,186 +67,82 @@ bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group)
 	return list_empty(&group->notification_list) ? true : false;
 }
 
-void fsnotify_get_event(struct fsnotify_event *event)
+void fsnotify_destroy_event(struct fsnotify_group *group,
+			    struct fsnotify_event *event)
 {
-	atomic_inc(&event->refcnt);
-}
-
-void fsnotify_put_event(struct fsnotify_event *event)
-{
-	if (!event)
+	/* Overflow events are per-group and we don't want to free them */
+	if (!event || event->mask == FS_Q_OVERFLOW)
 		return;
 
-	if (atomic_dec_and_test(&event->refcnt)) {
-		pr_debug("%s: event=%p\n", __func__, event);
-
-		if (event->data_type == FSNOTIFY_EVENT_PATH)
-			path_put(&event->path);
-
-		BUG_ON(!list_empty(&event->private_data_list));
-
-		kfree(event->file_name);
-		put_pid(event->tgid);
-		kmem_cache_free(fsnotify_event_cachep, event);
-	}
-}
-
-struct fsnotify_event_holder *fsnotify_alloc_event_holder(void)
-{
-	return kmem_cache_alloc(fsnotify_event_holder_cachep, GFP_KERNEL);
-}
-
-void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder)
-{
-	if (holder)
-		kmem_cache_free(fsnotify_event_holder_cachep, holder);
-}
-
-/*
- * Find the private data that the group previously attached to this event when
- * the group added the event to the notification queue (fsnotify_add_notify_event)
- */
-struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnotify_group *group, struct fsnotify_event *event)
-{
-	struct fsnotify_event_private_data *lpriv;
-	struct fsnotify_event_private_data *priv = NULL;
-
-	assert_spin_locked(&event->lock);
-
-	list_for_each_entry(lpriv, &event->private_data_list, event_list) {
-		if (lpriv->group == group) {
-			priv = lpriv;
-			list_del(&priv->event_list);
-			break;
-		}
-	}
-	return priv;
+	group->ops->free_event(event);
 }
 
 /*
  * Add an event to the group notification queue.  The group can later pull this
- * event off the queue to deal with.  If the event is successfully added to the
- * group's notification queue, a reference is taken on event.
+ * event off the queue to deal with.  The function returns 0 if the event was
+ * added to the queue, 1 if the event was merged with some other queued event,
+ * 2 if the queue of events has overflown.
  */
-struct fsnotify_event *fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event,
-						 struct fsnotify_event_private_data *priv,
-						 struct fsnotify_event *(*merge)(struct list_head *,
-										 struct fsnotify_event *))
+int fsnotify_add_notify_event(struct fsnotify_group *group,
+			      struct fsnotify_event *event,
+			      int (*merge)(struct list_head *,
+					   struct fsnotify_event *))
 {
-	struct fsnotify_event *return_event = NULL;
-	struct fsnotify_event_holder *holder = NULL;
+	int ret = 0;
 	struct list_head *list = &group->notification_list;
 
-	pr_debug("%s: group=%p event=%p priv=%p\n", __func__, group, event, priv);
-
-	/*
-	 * There is one fsnotify_event_holder embedded inside each fsnotify_event.
-	 * Check if we expect to be able to use that holder.  If not alloc a new
-	 * holder.
-	 * For the overflow event it's possible that something will use the in
-	 * event holder before we get the lock so we may need to jump back and
-	 * alloc a new holder, this can't happen for most events...
-	 */
-	if (!list_empty(&event->holder.event_list)) {
-alloc_holder:
-		holder = fsnotify_alloc_event_holder();
-		if (!holder)
-			return ERR_PTR(-ENOMEM);
-	}
+	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 
 	mutex_lock(&group->notification_mutex);
 
 	if (group->q_len >= group->max_events) {
-		event = q_overflow_event;
-
-		/*
-		 * we need to return the overflow event
-		 * which means we need a ref
-		 */
-		fsnotify_get_event(event);
-		return_event = event;
-
-		/* sorry, no private data on the overflow event */
-		priv = NULL;
-	}
-
-	if (!list_empty(list) && merge) {
-		struct fsnotify_event *tmp;
-
-		tmp = merge(list, event);
-		if (tmp) {
+		ret = 2;
+		/* Queue overflow event only if it isn't already queued */
+		if (!list_empty(&group->overflow_event->list)) {
 			mutex_unlock(&group->notification_mutex);
-
-			if (return_event)
-				fsnotify_put_event(return_event);
-			if (holder != &event->holder)
-				fsnotify_destroy_event_holder(holder);
-			return tmp;
+			return ret;
 		}
+		event = group->overflow_event;
+		goto queue;
 	}
 
-	spin_lock(&event->lock);
-
-	if (list_empty(&event->holder.event_list)) {
-		if (unlikely(holder))
-			fsnotify_destroy_event_holder(holder);
-		holder = &event->holder;
-	} else if (unlikely(!holder)) {
-		/* between the time we checked above and got the lock the in
-		 * event holder was used, go back and get a new one */
-		spin_unlock(&event->lock);
-		mutex_unlock(&group->notification_mutex);
-
-		if (return_event) {
-			fsnotify_put_event(return_event);
-			return_event = NULL;
+	if (!list_empty(list) && merge) {
+		ret = merge(list, event);
+		if (ret) {
+			mutex_unlock(&group->notification_mutex);
+			return ret;
 		}
-
-		goto alloc_holder;
 	}
 
+queue:
 	group->q_len++;
-	holder->event = event;
-
-	fsnotify_get_event(event);
-	list_add_tail(&holder->event_list, list);
-	if (priv)
-		list_add_tail(&priv->event_list, &event->private_data_list);
-	spin_unlock(&event->lock);
+	list_add_tail(&event->list, list);
 	mutex_unlock(&group->notification_mutex);
 
 	wake_up(&group->notification_waitq);
 	kill_fasync(&group->fsn_fa, SIGIO, POLL_IN);
-	return return_event;
+	return ret;
 }
 
 /*
- * Remove and return the first event from the notification list.  There is a
- * reference held on this event since it was on the list.  It is the responsibility
- * of the caller to drop this reference.
+ * Remove and return the first event from the notification list.  It is the
+ * responsibility of the caller to destroy the obtained event
  */
 struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group)
 {
 	struct fsnotify_event *event;
-	struct fsnotify_event_holder *holder;
 
 	BUG_ON(!mutex_is_locked(&group->notification_mutex));
 
 	pr_debug("%s: group=%p\n", __func__, group);
 
-	holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list);
-
-	event = holder->event;
-
-	spin_lock(&event->lock);
-	holder->event = NULL;
-	list_del_init(&holder->event_list);
-	spin_unlock(&event->lock);
-
-	/* event == holder means we are referenced through the in event holder */
-	if (holder != &event->holder)
-		fsnotify_destroy_event_holder(holder);
-
+	event = list_first_entry(&group->notification_list,
+				 struct fsnotify_event, list);
+	/*
+	 * We need to init list head for the case of overflow event so that
+	 * check in fsnotify_add_notify_events() works
+	 */
+	list_del_init(&event->list);
 	group->q_len--;
 
 	return event;
@@ -266,15 +153,10 @@ struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group
  */
 struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group)
 {
-	struct fsnotify_event *event;
-	struct fsnotify_event_holder *holder;
-
 	BUG_ON(!mutex_is_locked(&group->notification_mutex));
 
-	holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list);
-	event = holder->event;
-
-	return event;
+	return list_first_entry(&group->notification_list,
+				struct fsnotify_event, list);
 }
 
 /*
@@ -284,181 +166,31 @@ struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group)
 void fsnotify_flush_notify(struct fsnotify_group *group)
 {
 	struct fsnotify_event *event;
-	struct fsnotify_event_private_data *priv;
 
 	mutex_lock(&group->notification_mutex);
 	while (!fsnotify_notify_queue_is_empty(group)) {
 		event = fsnotify_remove_notify_event(group);
-		/* if they don't implement free_event_priv they better not have attached any */
-		if (group->ops->free_event_priv) {
-			spin_lock(&event->lock);
-			priv = fsnotify_remove_priv_from_event(group, event);
-			spin_unlock(&event->lock);
-			if (priv)
-				group->ops->free_event_priv(priv);
-		}
-		fsnotify_put_event(event); /* matches fsnotify_add_notify_event */
+		fsnotify_destroy_event(group, event);
 	}
 	mutex_unlock(&group->notification_mutex);
 }
 
-static void initialize_event(struct fsnotify_event *event)
-{
-	INIT_LIST_HEAD(&event->holder.event_list);
-	atomic_set(&event->refcnt, 1);
-
-	spin_lock_init(&event->lock);
-
-	INIT_LIST_HEAD(&event->private_data_list);
-}
-
-/*
- * Caller damn well better be holding whatever mutex is protecting the
- * old_holder->event_list and the new_event must be a clean event which
- * cannot be found anywhere else in the kernel.
- */
-int fsnotify_replace_event(struct fsnotify_event_holder *old_holder,
-			   struct fsnotify_event *new_event)
-{
-	struct fsnotify_event *old_event = old_holder->event;
-	struct fsnotify_event_holder *new_holder = &new_event->holder;
-
-	enum event_spinlock_class {
-		SPINLOCK_OLD,
-		SPINLOCK_NEW,
-	};
-
-	pr_debug("%s: old_event=%p new_event=%p\n", __func__, old_event, new_event);
-
-	/*
-	 * if the new_event's embedded holder is in use someone
-	 * screwed up and didn't give us a clean new event.
-	 */
-	BUG_ON(!list_empty(&new_holder->event_list));
-
-	spin_lock_nested(&old_event->lock, SPINLOCK_OLD);
-	spin_lock_nested(&new_event->lock, SPINLOCK_NEW);
-
-	new_holder->event = new_event;
-	list_replace_init(&old_holder->event_list, &new_holder->event_list);
-
-	spin_unlock(&new_event->lock);
-	spin_unlock(&old_event->lock);
-
-	/* event == holder means we are referenced through the in event holder */
-	if (old_holder != &old_event->holder)
-		fsnotify_destroy_event_holder(old_holder);
-
-	fsnotify_get_event(new_event); /* on the list take reference */
-	fsnotify_put_event(old_event); /* off the list, drop reference */
-
-	return 0;
-}
-
-struct fsnotify_event *fsnotify_clone_event(struct fsnotify_event *old_event)
-{
-	struct fsnotify_event *event;
-
-	event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL);
-	if (!event)
-		return NULL;
-
-	pr_debug("%s: old_event=%p new_event=%p\n", __func__, old_event, event);
-
-	memcpy(event, old_event, sizeof(*event));
-	initialize_event(event);
-
-	if (event->name_len) {
-		event->file_name = kstrdup(old_event->file_name, GFP_KERNEL);
-		if (!event->file_name) {
-			kmem_cache_free(fsnotify_event_cachep, event);
-			return NULL;
-		}
-	}
-	event->tgid = get_pid(old_event->tgid);
-	if (event->data_type == FSNOTIFY_EVENT_PATH)
-		path_get(&event->path);
-
-	return event;
-}
-
 /*
  * fsnotify_create_event - Allocate a new event which will be sent to each
  * group's handle_event function if the group was interested in this
  * particular event.
  *
- * @to_tell the inode which is supposed to receive the event (sometimes a
+ * @inode the inode which is supposed to receive the event (sometimes a
  *	parent of the inode to which the event happened.
  * @mask what actually happened.
  * @data pointer to the object which was actually affected
  * @data_type flag indication if the data is a file, path, inode, nothing...
  * @name the filename, if available
  */
-struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, void *data,
-					     int data_type, const unsigned char *name,
-					     u32 cookie, gfp_t gfp)
+void fsnotify_init_event(struct fsnotify_event *event, struct inode *inode,
+			 u32 mask)
 {
-	struct fsnotify_event *event;
-
-	event = kmem_cache_zalloc(fsnotify_event_cachep, gfp);
-	if (!event)
-		return NULL;
-
-	pr_debug("%s: event=%p to_tell=%p mask=%x data=%p data_type=%d\n",
-		 __func__, event, to_tell, mask, data, data_type);
-
-	initialize_event(event);
-
-	if (name) {
-		event->file_name = kstrdup(name, gfp);
-		if (!event->file_name) {
-			kmem_cache_free(fsnotify_event_cachep, event);
-			return NULL;
-		}
-		event->name_len = strlen(event->file_name);
-	}
-
-	event->tgid = get_pid(task_tgid(current));
-	event->sync_cookie = cookie;
-	event->to_tell = to_tell;
-	event->data_type = data_type;
-
-	switch (data_type) {
-	case FSNOTIFY_EVENT_PATH: {
-		struct path *path = data;
-		event->path.dentry = path->dentry;
-		event->path.mnt = path->mnt;
-		path_get(&event->path);
-		break;
-	}
-	case FSNOTIFY_EVENT_INODE:
-		event->inode = data;
-		break;
-	case FSNOTIFY_EVENT_NONE:
-		event->inode = NULL;
-		event->path.dentry = NULL;
-		event->path.mnt = NULL;
-		break;
-	default:
-		BUG();
-	}
-
+	INIT_LIST_HEAD(&event->list);
+	event->inode = inode;
 	event->mask = mask;
-
-	return event;
-}
-
-static __init int fsnotify_notification_init(void)
-{
-	fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC);
-	fsnotify_event_holder_cachep = KMEM_CACHE(fsnotify_event_holder, SLAB_PANIC);
-
-	q_overflow_event = fsnotify_create_event(NULL, FS_Q_OVERFLOW, NULL,
-						 FSNOTIFY_EVENT_NONE, NULL, 0,
-						 GFP_KERNEL);
-	if (!q_overflow_event)
-		panic("unable to allocate fsnotify q_overflow_event\n");
-
-	return 0;
 }
-subsys_initcall(fsnotify_notification_init);