mirror of
https://github.com/torvalds/linux.git
synced 2024-11-18 10:01:43 +00:00
191e1656d1
Call mutex_destroy() before freeing notification group. This only adds some additional debug checks when mutex debugging is enabled but still it may be useful. Link: https://lore.kernel.org/r/20200512181803.405832-1-fabf@skynet.be Signed-off-by: Fabian Frederick <fabf@skynet.be> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
150 lines
4.0 KiB
C
150 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
|
|
*/
|
|
|
|
#include <linux/list.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/srcu.h>
|
|
#include <linux/rculist.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/memcontrol.h>
|
|
|
|
#include <linux/fsnotify_backend.h>
|
|
#include "fsnotify.h"
|
|
|
|
#include <linux/atomic.h>
|
|
|
|
/*
|
|
* Final freeing of a group
|
|
*/
|
|
static void fsnotify_final_destroy_group(struct fsnotify_group *group)
|
|
{
|
|
if (group->ops->free_group_priv)
|
|
group->ops->free_group_priv(group);
|
|
|
|
mem_cgroup_put(group->memcg);
|
|
mutex_destroy(&group->mark_mutex);
|
|
|
|
kfree(group);
|
|
}
|
|
|
|
/*
|
|
* Stop queueing new events for this group. Once this function returns
|
|
* fsnotify_add_event() will not add any new events to the group's queue.
|
|
*/
|
|
void fsnotify_group_stop_queueing(struct fsnotify_group *group)
|
|
{
|
|
spin_lock(&group->notification_lock);
|
|
group->shutdown = true;
|
|
spin_unlock(&group->notification_lock);
|
|
}
|
|
|
|
/*
|
|
* Trying to get rid of a group. Remove all marks, flush all events and release
|
|
* the group reference.
|
|
* Note that another thread calling fsnotify_clear_marks_by_group() may still
|
|
* hold a ref to the group.
|
|
*/
|
|
void fsnotify_destroy_group(struct fsnotify_group *group)
|
|
{
|
|
/*
|
|
* Stop queueing new events. The code below is careful enough to not
|
|
* require this but fanotify needs to stop queuing events even before
|
|
* fsnotify_destroy_group() is called and this makes the other callers
|
|
* of fsnotify_destroy_group() to see the same behavior.
|
|
*/
|
|
fsnotify_group_stop_queueing(group);
|
|
|
|
/* Clear all marks for this group and queue them for destruction */
|
|
fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_ALL_TYPES_MASK);
|
|
|
|
/*
|
|
* Some marks can still be pinned when waiting for response from
|
|
* userspace. Wait for those now. fsnotify_prepare_user_wait() will
|
|
* not succeed now so this wait is race-free.
|
|
*/
|
|
wait_event(group->notification_waitq, !atomic_read(&group->user_waits));
|
|
|
|
/*
|
|
* Wait until all marks get really destroyed. We could actually destroy
|
|
* them ourselves instead of waiting for worker to do it, however that
|
|
* would be racy as worker can already be processing some marks before
|
|
* we even entered fsnotify_destroy_group().
|
|
*/
|
|
fsnotify_wait_marks_destroyed();
|
|
|
|
/*
|
|
* Since we have waited for fsnotify_mark_srcu in
|
|
* fsnotify_mark_destroy_list() there can be no outstanding event
|
|
* notification against this group. So clearing the notification queue
|
|
* of all events is reliable now.
|
|
*/
|
|
fsnotify_flush_notify(group);
|
|
|
|
/*
|
|
* Destroy overflow event (we cannot use fsnotify_destroy_event() as
|
|
* that deliberately ignores overflow events.
|
|
*/
|
|
if (group->overflow_event)
|
|
group->ops->free_event(group->overflow_event);
|
|
|
|
fsnotify_put_group(group);
|
|
}
|
|
|
|
/*
|
|
* Get reference to a group.
|
|
*/
|
|
void fsnotify_get_group(struct fsnotify_group *group)
|
|
{
|
|
refcount_inc(&group->refcnt);
|
|
}
|
|
|
|
/*
|
|
* Drop a reference to a group. Free it if it's through.
|
|
*/
|
|
void fsnotify_put_group(struct fsnotify_group *group)
|
|
{
|
|
if (refcount_dec_and_test(&group->refcnt))
|
|
fsnotify_final_destroy_group(group);
|
|
}
|
|
EXPORT_SYMBOL_GPL(fsnotify_put_group);
|
|
|
|
/*
|
|
* Create a new fsnotify_group and hold a reference for the group returned.
|
|
*/
|
|
struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
|
|
{
|
|
struct fsnotify_group *group;
|
|
|
|
group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
|
|
if (!group)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/* set to 0 when there a no external references to this group */
|
|
refcount_set(&group->refcnt, 1);
|
|
atomic_set(&group->num_marks, 0);
|
|
atomic_set(&group->user_waits, 0);
|
|
|
|
spin_lock_init(&group->notification_lock);
|
|
INIT_LIST_HEAD(&group->notification_list);
|
|
init_waitqueue_head(&group->notification_waitq);
|
|
group->max_events = UINT_MAX;
|
|
|
|
mutex_init(&group->mark_mutex);
|
|
INIT_LIST_HEAD(&group->marks_list);
|
|
|
|
group->ops = ops;
|
|
|
|
return group;
|
|
}
|
|
EXPORT_SYMBOL_GPL(fsnotify_alloc_group);
|
|
|
|
int fsnotify_fasync(int fd, struct file *file, int on)
|
|
{
|
|
struct fsnotify_group *group = file->private_data;
|
|
|
|
return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
|
|
}
|