On Wed, Feb 13, 2019 at 4:54 PM Jan Kara <jack@xxxxxxx> wrote:
>
> get_one_event() has a single caller and that just locks
> notification_lock around the call. Move locking inside get_one_event()
> as that will make using ->response field for permission event state
> easier.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/notify/fanotify/fanotify_user.c | 25 +++++++++++--------------
> 1 file changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 908ebc421d15..4e36f5642797 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -51,25 +51,25 @@ struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
> * Get an fsnotify notification event if one exists and is small
> * enough to fit in "count". Return an error pointer if the count
> * is not large enough.
> - *
> - * Called with the group->notification_lock held.
> */
> static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
> size_t count)
> {
> - assert_spin_locked(&group->notification_lock);
> + struct fsnotify_event *event = NULL;
>
> pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
> -
> + spin_lock(&group->notification_lock);
> if (fsnotify_notify_queue_is_empty(group))
> - return NULL;
> + goto out;
>
> - if (FAN_EVENT_METADATA_LEN > count)
> - return ERR_PTR(-EINVAL);
> -
> - /* held the notification_lock the whole time, so this is the
> - * same event we peeked above */
> - return fsnotify_remove_first_event(group);
> + if (FAN_EVENT_METADATA_LEN > count) {
> + event = ERR_PTR(-EINVAL);
> + goto out;
> + }
> + event = fsnotify_remove_first_event(group);
> +out:
> + spin_unlock(&group->notification_lock);
> + return event;
> }
>
> static int create_fd(struct fsnotify_group *group,
> @@ -261,10 +261,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
>
> add_wait_queue(&group->notification_waitq, &wait);
> while (1) {
> - spin_lock(&group->notification_lock);
> kevent = get_one_event(group, count);
> - spin_unlock(&group->notification_lock);
> -
> if (IS_ERR(kevent)) {
> ret = PTR_ERR(kevent);
> break;
> --
> 2.16.4
>
