c82ee6d3be
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 52 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154042.342335923@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
147 lines
3.9 KiB
C
147 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
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*/
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/srcu.h>
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#include <linux/rculist.h>
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#include <linux/wait.h>
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#include <linux/memcontrol.h>
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#include <linux/fsnotify_backend.h>
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#include "fsnotify.h"
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#include <linux/atomic.h>
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/*
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* Final freeing of a group
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*/
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static void fsnotify_final_destroy_group(struct fsnotify_group *group)
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{
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if (group->ops->free_group_priv)
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group->ops->free_group_priv(group);
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mem_cgroup_put(group->memcg);
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kfree(group);
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}
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/*
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* Stop queueing new events for this group. Once this function returns
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* fsnotify_add_event() will not add any new events to the group's queue.
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*/
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void fsnotify_group_stop_queueing(struct fsnotify_group *group)
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{
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spin_lock(&group->notification_lock);
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group->shutdown = true;
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spin_unlock(&group->notification_lock);
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}
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/*
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* Trying to get rid of a group. Remove all marks, flush all events and release
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* the group reference.
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* Note that another thread calling fsnotify_clear_marks_by_group() may still
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* hold a ref to the group.
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*/
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void fsnotify_destroy_group(struct fsnotify_group *group)
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{
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/*
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* Stop queueing new events. The code below is careful enough to not
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* require this but fanotify needs to stop queuing events even before
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* fsnotify_destroy_group() is called and this makes the other callers
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* of fsnotify_destroy_group() to see the same behavior.
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*/
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fsnotify_group_stop_queueing(group);
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/* Clear all marks for this group and queue them for destruction */
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fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_ALL_TYPES_MASK);
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/*
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* Some marks can still be pinned when waiting for response from
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* userspace. Wait for those now. fsnotify_prepare_user_wait() will
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* not succeed now so this wait is race-free.
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*/
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wait_event(group->notification_waitq, !atomic_read(&group->user_waits));
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/*
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* Wait until all marks get really destroyed. We could actually destroy
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* them ourselves instead of waiting for worker to do it, however that
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* would be racy as worker can already be processing some marks before
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* we even entered fsnotify_destroy_group().
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*/
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fsnotify_wait_marks_destroyed();
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/*
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* Since we have waited for fsnotify_mark_srcu in
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* fsnotify_mark_destroy_list() there can be no outstanding event
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* notification against this group. So clearing the notification queue
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* of all events is reliable now.
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*/
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fsnotify_flush_notify(group);
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/*
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* Destroy overflow event (we cannot use fsnotify_destroy_event() as
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* that deliberately ignores overflow events.
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*/
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if (group->overflow_event)
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group->ops->free_event(group->overflow_event);
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fsnotify_put_group(group);
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}
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/*
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* Get reference to a group.
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*/
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void fsnotify_get_group(struct fsnotify_group *group)
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{
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refcount_inc(&group->refcnt);
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}
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/*
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* Drop a reference to a group. Free it if it's through.
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*/
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void fsnotify_put_group(struct fsnotify_group *group)
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{
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if (refcount_dec_and_test(&group->refcnt))
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fsnotify_final_destroy_group(group);
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}
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/*
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* Create a new fsnotify_group and hold a reference for the group returned.
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*/
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struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
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{
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struct fsnotify_group *group;
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group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
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if (!group)
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return ERR_PTR(-ENOMEM);
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/* set to 0 when there a no external references to this group */
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refcount_set(&group->refcnt, 1);
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atomic_set(&group->num_marks, 0);
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atomic_set(&group->user_waits, 0);
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spin_lock_init(&group->notification_lock);
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INIT_LIST_HEAD(&group->notification_list);
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init_waitqueue_head(&group->notification_waitq);
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group->max_events = UINT_MAX;
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mutex_init(&group->mark_mutex);
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INIT_LIST_HEAD(&group->marks_list);
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group->ops = ops;
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return group;
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}
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int fsnotify_fasync(int fd, struct file *file, int on)
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{
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struct fsnotify_group *group = file->private_data;
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return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
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}
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