From b8a6c3a2f0ae4d82732810e55ca8aa455e040bbf Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 8 Jul 2020 14:11:42 +0300 Subject: fanotify: create overflow event type The special overflow event is allocated as struct fanotify_path_event, but with a null path. Use a special event type to identify the overflow event, so the helper fanotify_has_event_path() will always indicate a non null path. Allocating the overflow event doesn't need any of the fancy stuff in fanotify_alloc_event(), so create a simplified helper for allocating the overflow event. There is also no need to store and report the pid with an overflow event. Link: https://lore.kernel.org/r/20200708111156.24659-7-amir73il@gmail.com Suggested-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara --- fs/notify/fanotify/fanotify_user.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'fs/notify/fanotify/fanotify_user.c') diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index d7f63aeca992..c9a824e5c045 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -836,13 +836,26 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group, FSNOTIFY_OBJ_TYPE_INODE, mask, flags, fsid); } +static struct fsnotify_event *fanotify_alloc_overflow_event(void) +{ + struct fanotify_event *oevent; + + oevent = kmalloc(sizeof(*oevent), GFP_KERNEL_ACCOUNT); + if (!oevent) + return NULL; + + fanotify_init_event(oevent, 0, FS_Q_OVERFLOW); + oevent->type = FANOTIFY_EVENT_TYPE_OVERFLOW; + + return &oevent->fse; +} + /* fanotify syscalls */ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) { struct fsnotify_group *group; int f_flags, fd; struct user_struct *user; - struct fanotify_event *oevent; pr_debug("%s: flags=%x event_f_flags=%x\n", __func__, flags, event_f_flags); @@ -897,13 +910,11 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) atomic_inc(&user->fanotify_listeners); group->memcg = get_mem_cgroup_from_mm(current->mm); - oevent = fanotify_alloc_event(group, NULL, FS_Q_OVERFLOW, NULL, - FSNOTIFY_EVENT_NONE, NULL, NULL); - if (unlikely(!oevent)) { + group->overflow_event = fanotify_alloc_overflow_event(); + if (unlikely(!group->overflow_event)) { fd = -ENOMEM; goto out_destroy_group; } - group->overflow_event = &oevent->fse; if (force_o_largefile()) event_f_flags |= O_LARGEFILE; -- cgit v1.2.3