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Commit 74be0cc8 authored by Eric Paris's avatar Eric Paris
Browse files

fsnotify: remove group_num altogether 



The original fsnotify interface has a group-num which was intended to be
able to find a group after it was added.  I no longer think this is a
necessary thing to do and so we remove the group_num.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent cac69dad

fs/notify/dnotify/dnotify.c

+1 −2
Original line number Diff line number Diff line
@@ -433,8 +433,7 @@ static int __init dnotify_init(void) 
	dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC);

	dnotify_mark_entry_cache = KMEM_CACHE(dnotify_mark_entry, SLAB_PANIC);



	dnotify_group = fsnotify_obtain_group(DNOTIFY_GROUP_NUM,

					      0, &dnotify_fsnotify_ops);

	dnotify_group = fsnotify_obtain_group(0, &dnotify_fsnotify_ops);

	if (IS_ERR(dnotify_group))

		panic("unable to allocate fsnotify group for dnotify\n");

	return 0;

fs/notify/group.c

+2 −46
Original line number Diff line number Diff line
@@ -77,15 +77,6 @@ void fsnotify_recalc_group_mask(struct fsnotify_group *group) 
		fsnotify_recalc_global_mask();

}



/*

 * Take a reference to a group so things found under the fsnotify_grp_mutex

 * can't get freed under us

 */

static void fsnotify_get_group(struct fsnotify_group *group)

{

	atomic_inc(&group->refcnt);

}



/*

 * Final freeing of a group

 */
@@ -170,41 +161,15 @@ void fsnotify_put_group(struct fsnotify_group *group) 
	fsnotify_destroy_group(group);

}



/*

 * Simply run the fsnotify_groups list and find a group which matches

 * the given parameters.  If a group is found we take a reference to that

 * group.

 */

static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask,

						  const struct fsnotify_ops *ops)

{

	struct fsnotify_group *group_iter;

	struct fsnotify_group *group = NULL;



	BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));



	list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) {

		if (group_iter->group_num == group_num) {

			if ((group_iter->mask == mask) &&

			    (group_iter->ops == ops)) {

				fsnotify_get_group(group_iter);

				group = group_iter;

			} else

				group = ERR_PTR(-EEXIST);

		}

	}

	return group;

}



/*

 * Either finds an existing group which matches the group_num, mask, and ops or

 * creates a new group and adds it to the global group list.  In either case we

 * take a reference for the group returned.

 */

struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,

struct fsnotify_group *fsnotify_obtain_group(__u32 mask,

					     const struct fsnotify_ops *ops)

{

	struct fsnotify_group *group, *tgroup;

	struct fsnotify_group *group;



	/* very low use, simpler locking if we just always alloc */

	group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
@@ -214,7 +179,6 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, 
	atomic_set(&group->refcnt, 1);



	group->on_group_list = 0;

	group->group_num = group_num;

	group->mask = mask;



	mutex_init(&group->notification_mutex);
@@ -230,14 +194,6 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, 
	group->ops = ops;



	mutex_lock(&fsnotify_grp_mutex);

	tgroup = fsnotify_find_group(group_num, mask, ops);

	if (tgroup) {

		/* group already exists */

		mutex_unlock(&fsnotify_grp_mutex);

		/* destroy the new one we made */

		fsnotify_put_group(group);

		return tgroup;

	}



	/* group not found, add a new one */

	list_add_rcu(&group->group_list, &fsnotify_groups);

fs/notify/inotify/inotify_user.c

+1 −10
Original line number Diff line number Diff line
@@ -51,12 +51,6 @@ int inotify_max_user_watches __read_mostly; 
static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;

struct kmem_cache *event_priv_cachep __read_mostly;



/*

 * When inotify registers a new group it increments this and uses that

 * value as an offset to set the fsnotify group "name" and priority.

 */

static atomic_t inotify_grp_num;



#ifdef CONFIG_SYSCTL



#include <linux/sysctl.h>
@@ -700,11 +694,8 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod 
static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events)

{

	struct fsnotify_group *group;

	unsigned int grp_num;



	/* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */

	grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num));

	group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops);

	group = fsnotify_obtain_group(0, &inotify_fsnotify_ops);

	if (IS_ERR(group))

		return group;

include/linux/fsnotify_backend.h

+1 −9
Original line number Diff line number Diff line
@@ -60,12 +60,6 @@ 


#define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)



/* listeners that hard code group numbers near the top */

#define DNOTIFY_GROUP_NUM	UINT_MAX

#define AUDIT_WATCH_GROUP_NUM	(DNOTIFY_GROUP_NUM-1)

#define AUDIT_TREE_GROUP_NUM	(AUDIT_WATCH_GROUP_NUM-1)

#define INOTIFY_GROUP_NUM	(AUDIT_TREE_GROUP_NUM-1)



struct fsnotify_group;

struct fsnotify_event;

struct fsnotify_mark_entry;
@@ -124,7 +118,6 @@ struct fsnotify_group { 
	 * closed.

	 */

	atomic_t refcnt;		/* things with interest in this group */

	unsigned int group_num;		/* simply prevents accidental group collision */



	const struct fsnotify_ops *ops;	/* how this group handles things */
@@ -312,8 +305,7 @@ static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode 
/* must call when a group changes its ->mask */

extern void fsnotify_recalc_global_mask(void);

/* get a reference to an existing or create a new group */

extern struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num,

						    __u32 mask,

extern struct fsnotify_group *fsnotify_obtain_group(__u32 mask,

						    const struct fsnotify_ops *ops);

/* run all marks associated with this group and update group->mask */

extern void fsnotify_recalc_group_mask(struct fsnotify_group *group);

kernel/audit_tree.c

+1 −2
Original line number Diff line number Diff line
@@ -937,8 +937,7 @@ static int __init audit_tree_init(void) 
{

	int i;



	audit_tree_group = fsnotify_obtain_group(AUDIT_TREE_GROUP_NUM,

						 0, &audit_tree_ops);

	audit_tree_group = fsnotify_obtain_group(0, &audit_tree_ops);

	if (IS_ERR(audit_tree_group))

		audit_panic("cannot initialize fsnotify group for rectree watches");