diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 9e0c1afac8bd..16162207e886 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -100,24 +100,30 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group, { size_t event_size = FAN_EVENT_METADATA_LEN; struct fanotify_event *event = NULL; + struct fsnotify_event *fsn_event; unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); pr_debug("%s: group=%p count=%zd\n", __func__, group, count); spin_lock(&group->notification_lock); - if (fsnotify_notify_queue_is_empty(group)) + fsn_event = fsnotify_peek_first_event(group); + if (!fsn_event) goto out; - if (fid_mode) { - event_size += fanotify_event_info_len(fid_mode, - FANOTIFY_E(fsnotify_peek_first_event(group))); - } + event = FANOTIFY_E(fsn_event); + if (fid_mode) + event_size += fanotify_event_info_len(fid_mode, event); if (event_size > count) { event = ERR_PTR(-EINVAL); goto out; } - event = FANOTIFY_E(fsnotify_remove_first_event(group)); + + /* + * Held the notification_lock the whole time, so this is the + * same event we peeked above. + */ + fsnotify_remove_first_event(group); if (fanotify_is_perm_event(event->mask)) FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED; out: @@ -573,6 +579,7 @@ static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t static int fanotify_release(struct inode *ignored, struct file *file) { struct fsnotify_group *group = file->private_data; + struct fsnotify_event *fsn_event; /* * Stop new events from arriving in the notification queue. since @@ -601,13 +608,12 @@ static int fanotify_release(struct inode *ignored, struct file *file) * dequeue them and set the response. They will be freed once the * response is consumed and fanotify_get_response() returns. */ - while (!fsnotify_notify_queue_is_empty(group)) { - struct fanotify_event *event; + while ((fsn_event = fsnotify_remove_first_event(group))) { + struct fanotify_event *event = FANOTIFY_E(fsn_event); - event = FANOTIFY_E(fsnotify_remove_first_event(group)); if (!(event->mask & FANOTIFY_PERM_EVENTS)) { spin_unlock(&group->notification_lock); - fsnotify_destroy_event(group, &event->fse); + fsnotify_destroy_event(group, fsn_event); } else { finish_permission_event(group, FANOTIFY_PERM(event), FAN_ALLOW); diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index c71be4fb7dc5..a6c95bd64618 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -146,10 +146,9 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group, size_t event_size = sizeof(struct inotify_event); struct fsnotify_event *event; - if (fsnotify_notify_queue_is_empty(group)) - return NULL; - event = fsnotify_peek_first_event(group); + if (!event) + return NULL; pr_debug("%s: group=%p event=%p\n", __func__, group, event); diff --git a/fs/notify/notification.c b/fs/notify/notification.c index 75d79d6d3ef0..001cfe7d2e4e 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -47,13 +47,6 @@ u32 fsnotify_get_cookie(void) } EXPORT_SYMBOL_GPL(fsnotify_get_cookie); -/* return true if the notify queue is empty, false otherwise */ -bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group) -{ - assert_spin_locked(&group->notification_lock); - return list_empty(&group->notification_list) ? true : false; -} - void fsnotify_destroy_event(struct fsnotify_group *group, struct fsnotify_event *event) { @@ -141,35 +134,38 @@ void fsnotify_remove_queued_event(struct fsnotify_group *group, } /* - * Remove and return the first event from the notification list. It is the - * responsibility of the caller to destroy the obtained event - */ -struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group) -{ - struct fsnotify_event *event; - - assert_spin_locked(&group->notification_lock); - - pr_debug("%s: group=%p\n", __func__, group); - - event = list_first_entry(&group->notification_list, - struct fsnotify_event, list); - fsnotify_remove_queued_event(group, event); - return event; -} - -/* - * This will not remove the event, that must be done with - * fsnotify_remove_first_event() + * Return the first event on the notification list without removing it. + * Returns NULL if the list is empty. */ struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group) { assert_spin_locked(&group->notification_lock); + if (fsnotify_notify_queue_is_empty(group)) + return NULL; + return list_first_entry(&group->notification_list, struct fsnotify_event, list); } +/* + * Remove and return the first event from the notification list. It is the + * responsibility of the caller to destroy the obtained event + */ +struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group) +{ + struct fsnotify_event *event = fsnotify_peek_first_event(group); + + if (!event) + return NULL; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + fsnotify_remove_queued_event(group, event); + + return event; +} + /* * Called when a group is being torn down to clean up any outstanding * event notifications. diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index e5409b83e731..7eb979bfc141 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -495,7 +495,13 @@ static inline void fsnotify_queue_overflow(struct fsnotify_group *group) fsnotify_add_event(group, group->overflow_event, NULL); } -/* true if the group notification queue is empty */ +static inline bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group) +{ + assert_spin_locked(&group->notification_lock); + + return list_empty(&group->notification_list); +} + extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group); /* return, but do not dequeue the first event on the notification queue */ extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group);