The patch titled
Subject: fanotify: use notification_lock instead of access_lock
has been added to the -mm tree. Its filename is
fanotify-use-notification_lock-instead-of-access_lock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fanotify-use-notification_lock-instead-of-access_lock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fanotify-use-notification_lock-instead-of-access_lock.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Jan Kara <jack@xxxxxxx>
Subject: fanotify: use notification_lock instead of access_lock
Fanotify code has an own lock (access_lock) to protect a list of events
waiting for a response from userspace. However this is somewhat awkward
as the same list_head in the event is protected by notification_lock if it
is part of the notification queue and by access_lock if it is part of the
fanotify private queue which makes it difficult for any reliable checks in
the generic code. So make fanotify use the same lock - notification_lock
- for protecting its private event list.
Link: http://lkml.kernel.org/r/1473797711-14111-6-git-send-email-jack@xxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
Cc: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Cc: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 13 +++++--------
include/linux/fsnotify_backend.h | 1 -
2 files changed, 5 insertions(+), 9 deletions(-)
diff -puN fs/notify/fanotify/fanotify_user.c~fanotify-use-notification_lock-instead-of-access_lock fs/notify/fanotify/fanotify_user.c
--- a/fs/notify/fanotify/fanotify_user.c~fanotify-use-notification_lock-instead-of-access_lock
+++ a/fs/notify/fanotify/fanotify_user.c
@@ -147,7 +147,7 @@ static struct fanotify_perm_event_info *
{
struct fanotify_perm_event_info *event, *return_e = NULL;
- spin_lock(&group->fanotify_data.access_lock);
+ spin_lock(&group->notification_lock);
list_for_each_entry(event, &group->fanotify_data.access_list,
fae.fse.list) {
if (event->fd != fd)
@@ -157,7 +157,7 @@ static struct fanotify_perm_event_info *
return_e = event;
break;
}
- spin_unlock(&group->fanotify_data.access_lock);
+ spin_unlock(&group->notification_lock);
pr_debug("%s: found return_re=%p\n", __func__, return_e);
@@ -309,10 +309,10 @@ static ssize_t fanotify_read(struct file
wake_up(&group->fanotify_data.access_waitq);
break;
}
- spin_lock(&group->fanotify_data.access_lock);
+ spin_lock(&group->notification_lock);
list_add_tail(&kevent->list,
&group->fanotify_data.access_list);
- spin_unlock(&group->fanotify_data.access_lock);
+ spin_unlock(&group->notification_lock);
#endif
}
buf += ret;
@@ -371,7 +371,7 @@ static int fanotify_release(struct inode
* Process all permission events on access_list and notification queue
* and simulate reply from userspace.
*/
- spin_lock(&group->fanotify_data.access_lock);
+ spin_lock(&group->notification_lock);
list_for_each_entry_safe(event, next, &group->fanotify_data.access_list,
fae.fse.list) {
pr_debug("%s: found group=%p event=%p\n", __func__, group,
@@ -380,14 +380,12 @@ static int fanotify_release(struct inode
list_del_init(&event->fae.fse.list);
event->response = FAN_ALLOW;
}
- spin_unlock(&group->fanotify_data.access_lock);
/*
* Destroy all non-permission events. For permission events just
* dequeue them and set the response. They will be freed once the
* response is consumed and fanotify_get_response() returns.
*/
- spin_lock(&group->notification_lock);
while (!fsnotify_notify_queue_is_empty(group)) {
fsn_event = fsnotify_remove_first_event(group);
if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS)) {
@@ -767,7 +765,6 @@ SYSCALL_DEFINE2(fanotify_init, unsigned
event_f_flags |= O_LARGEFILE;
group->fanotify_data.f_flags = event_f_flags;
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
- spin_lock_init(&group->fanotify_data.access_lock);
init_waitqueue_head(&group->fanotify_data.access_waitq);
INIT_LIST_HEAD(&group->fanotify_data.access_list);
#endif
diff -puN include/linux/fsnotify_backend.h~fanotify-use-notification_lock-instead-of-access_lock include/linux/fsnotify_backend.h
--- a/include/linux/fsnotify_backend.h~fanotify-use-notification_lock-instead-of-access_lock
+++ a/include/linux/fsnotify_backend.h
@@ -177,7 +177,6 @@ struct fsnotify_group {
struct fanotify_group_private_data {
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
/* allows a group to block waiting for a userspace response */
- spinlock_t access_lock;
struct list_head access_list;
wait_queue_head_t access_waitq;
#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
_
Patches currently in -mm which might be from jack@xxxxxxx are
fsnotify-add-a-way-to-stop-queueing-events-on-group-shutdown.patch
fanotify-fix-list-corruption-in-fanotify_get_response.patch
fsnotify-drop-notification_mutex-before-destroying-event.patch
fsnotify-convert-notification_mutex-to-a-spinlock.patch
fanotify-use-notification_lock-instead-of-access_lock.patch
fanotify-fix-possible-false-warning-when-freeing-events.patch
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