mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-17 01:04:19 +08:00
60063497a9
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
105 lines
3.0 KiB
C
105 lines
3.0 KiB
C
/*
|
|
* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2, or (at your option)
|
|
* any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; see the file COPYING. If not, write to
|
|
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#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/fsnotify_backend.h>
|
|
#include "fsnotify.h"
|
|
|
|
#include <linux/atomic.h>
|
|
|
|
/*
|
|
* Final freeing of a group
|
|
*/
|
|
void fsnotify_final_destroy_group(struct fsnotify_group *group)
|
|
{
|
|
/* clear the notification queue of all events */
|
|
fsnotify_flush_notify(group);
|
|
|
|
if (group->ops->free_group_priv)
|
|
group->ops->free_group_priv(group);
|
|
|
|
kfree(group);
|
|
}
|
|
|
|
/*
|
|
* Trying to get rid of a group. We need to first get rid of any outstanding
|
|
* allocations and then free the group. Remember that fsnotify_clear_marks_by_group
|
|
* could miss marks that are being freed by inode and those marks could still
|
|
* hold a reference to this group (via group->num_marks) If we get into that
|
|
* situtation, the fsnotify_final_destroy_group will get called when that final
|
|
* mark is freed.
|
|
*/
|
|
static void fsnotify_destroy_group(struct fsnotify_group *group)
|
|
{
|
|
/* clear all inode marks for this group */
|
|
fsnotify_clear_marks_by_group(group);
|
|
|
|
synchronize_srcu(&fsnotify_mark_srcu);
|
|
|
|
/* past the point of no return, matches the initial value of 1 */
|
|
if (atomic_dec_and_test(&group->num_marks))
|
|
fsnotify_final_destroy_group(group);
|
|
}
|
|
|
|
/*
|
|
* Drop a reference to a group. Free it if it's through.
|
|
*/
|
|
void fsnotify_put_group(struct fsnotify_group *group)
|
|
{
|
|
if (atomic_dec_and_test(&group->refcnt))
|
|
fsnotify_destroy_group(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 */
|
|
atomic_set(&group->refcnt, 1);
|
|
/*
|
|
* hits 0 when there are no external references AND no marks for
|
|
* this group
|
|
*/
|
|
atomic_set(&group->num_marks, 1);
|
|
|
|
mutex_init(&group->notification_mutex);
|
|
INIT_LIST_HEAD(&group->notification_list);
|
|
init_waitqueue_head(&group->notification_waitq);
|
|
group->max_events = UINT_MAX;
|
|
|
|
spin_lock_init(&group->mark_lock);
|
|
INIT_LIST_HEAD(&group->marks_list);
|
|
|
|
group->ops = ops;
|
|
|
|
return group;
|
|
}
|