diff options
| -rw-r--r-- | fs/eventpoll.c | 46 | ||||
| -rw-r--r-- | include/linux/eventpoll.h | 9 |
2 files changed, 42 insertions, 13 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index cd848e8d08e2..b041b66002db 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -354,12 +354,6 @@ static inline struct epitem *ep_item_from_epqueue(poll_table *p) return container_of(p, struct ep_pqueue, pt)->epi; } -/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ -static inline int ep_op_has_event(int op) -{ - return op != EPOLL_CTL_DEL; -} - /* Initialize the poll safe wake up structure */ static void ep_nested_calls_init(struct nested_calls *ncalls) { @@ -2074,7 +2068,20 @@ SYSCALL_DEFINE1(epoll_create, int, size) return do_epoll_create(0); } -static int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds) +static inline int epoll_mutex_lock(struct mutex *mutex, int depth, + bool nonblock) +{ + if (!nonblock) { + mutex_lock_nested(mutex, depth); + return 0; + } + if (mutex_trylock(mutex)) + return 0; + return -EAGAIN; +} + +int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, + bool nonblock) { int error; int full_check = 0; @@ -2145,13 +2152,17 @@ static int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds) * deep wakeup paths from forming in parallel through multiple * EPOLL_CTL_ADD operations. */ - mutex_lock_nested(&ep->mtx, 0); + error = epoll_mutex_lock(&ep->mtx, 0, nonblock); + if (error) + goto error_tgt_fput; if (op == EPOLL_CTL_ADD) { if (!list_empty(&f.file->f_ep_links) || is_file_epoll(tf.file)) { - full_check = 1; mutex_unlock(&ep->mtx); - mutex_lock(&epmutex); + error = epoll_mutex_lock(&epmutex, 0, nonblock); + if (error) + goto error_tgt_fput; + full_check = 1; if (is_file_epoll(tf.file)) { error = -ELOOP; if (ep_loop_check(ep, tf.file) != 0) { @@ -2161,10 +2172,19 @@ static int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds) } else list_add(&tf.file->f_tfile_llink, &tfile_check_list); - mutex_lock_nested(&ep->mtx, 0); + error = epoll_mutex_lock(&ep->mtx, 0, nonblock); + if (error) { +out_del: + list_del(&tf.file->f_tfile_llink); + goto error_tgt_fput; + } if (is_file_epoll(tf.file)) { tep = tf.file->private_data; - mutex_lock_nested(&tep->mtx, 1); + error = epoll_mutex_lock(&tep->mtx, 1, nonblock); + if (error) { + mutex_unlock(&ep->mtx); + goto out_del; + } } } } @@ -2233,7 +2253,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, copy_from_user(&epds, event, sizeof(struct epoll_event))) return -EFAULT; - return do_epoll_ctl(epfd, op, fd, &epds); + return do_epoll_ctl(epfd, op, fd, &epds, false); } /* diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h index bc6d79b00c4e..8f000fada5a4 100644 --- a/include/linux/eventpoll.h +++ b/include/linux/eventpoll.h @@ -61,6 +61,15 @@ static inline void eventpoll_release(struct file *file) eventpoll_release_file(file); } +int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, + bool nonblock); + +/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ +static inline int ep_op_has_event(int op) +{ + return op != EPOLL_CTL_DEL; +} + #else static inline void eventpoll_init_file(struct file *file) {} |