From e3e096e7fc30c28cfc53fe8a1e265d65b85f60bb Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 26 Sep 2020 18:09:29 -0400 Subject: ep_insert(): don't open-code ep_remove() on failure exits Signed-off-by: Al Viro --- fs/eventpoll.c | 51 ++++++++++++++------------------------------------- 1 file changed, 14 insertions(+), 37 deletions(-) (limited to 'fs/eventpoll.c') diff --git a/fs/eventpoll.c b/fs/eventpoll.c index f9c567af1f5f..c987b61701e4 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1384,12 +1384,16 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, epi->next = EP_UNACTIVE_PTR; if (epi->event.events & EPOLLWAKEUP) { error = ep_create_wakeup_source(epi); - if (error) - goto error_create_wakeup_source; + if (error) { + kmem_cache_free(epi_cache, epi); + return error; + } } else { RCU_INIT_POINTER(epi->ws, NULL); } + atomic_long_inc(&ep->user->epoll_watches); + /* Add the current item to the list of active epoll hook for this file */ spin_lock(&tfile->f_lock); list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); @@ -1402,9 +1406,10 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, ep_rbtree_insert(ep, epi); /* now check if we've created too many backpaths */ - error = -EINVAL; - if (full_check && reverse_path_check()) - goto error_remove_epi; + if (unlikely(full_check && reverse_path_check())) { + ep_remove(ep, epi); + return -EINVAL; + } /* Initialize the poll table using the queue callback */ epq.epi = epi; @@ -1424,9 +1429,10 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, * install process. Namely an allocation for a wait queue failed due * high memory pressure. */ - error = -ENOMEM; - if (!epq.epi) - goto error_unregister; + if (unlikely(!epq.epi)) { + ep_remove(ep, epi); + return -ENOMEM; + } /* We have to drop the new item inside our item list to keep track of it */ write_lock_irq(&ep->lock); @@ -1448,40 +1454,11 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, write_unlock_irq(&ep->lock); - atomic_long_inc(&ep->user->epoll_watches); - /* We have to call this outside the lock */ if (pwake) ep_poll_safewake(ep, NULL); return 0; - -error_unregister: - ep_unregister_pollwait(ep, epi); -error_remove_epi: - spin_lock(&tfile->f_lock); - list_del_rcu(&epi->fllink); - spin_unlock(&tfile->f_lock); - - rb_erase_cached(&epi->rbn, &ep->rbr); - - /* - * We need to do this because an event could have been arrived on some - * allocated wait queue. Note that we don't care about the ep->ovflist - * list, since that is used/cleaned only inside a section bound by "mtx". - * And ep_insert() is called with "mtx" held. - */ - write_lock_irq(&ep->lock); - if (ep_is_linked(epi)) - list_del_init(&epi->rdllink); - write_unlock_irq(&ep->lock); - - wakeup_source_unregister(ep_wakeup_source(epi)); - -error_create_wakeup_source: - kmem_cache_free(epi_cache, epi); - - return error; } /* -- cgit v1.2.3-59-g8ed1b