Commit 39220e8d authored by Jens Axboe's avatar Jens Axboe
Browse files

eventpoll: support non-blocking do_epoll_ctl() calls 



Also make it available outside of epoll, along with the helper that
decides if we need to copy the passed in epoll_event.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 58e41a44

fs/eventpoll.c

+33 −13
Original line number Original line Diff line number Diff line
@@ -354,12 +354,6 @@ static inline struct epitem *ep_item_from_epqueue(poll_table *p) 
	return container_of(p, struct ep_pqueue, pt)->epi;

	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 */

/* Initialize the poll safe wake up structure */

static void ep_nested_calls_init(struct nested_calls *ncalls)

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);

	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 error;

	int full_check = 0;

	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

	 * deep wakeup paths from forming in parallel through multiple

	 * EPOLL_CTL_ADD operations.

	 * 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 (op == EPOLL_CTL_ADD) {

		if (!list_empty(&f.file->f_ep_links) ||

		if (!list_empty(&f.file->f_ep_links) ||

						is_file_epoll(tf.file)) {

						is_file_epoll(tf.file)) {

			full_check = 1;

			mutex_unlock(&ep->mtx);

			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)) {

			if (is_file_epoll(tf.file)) {

				error = -ELOOP;

				error = -ELOOP;

				if (ep_loop_check(ep, tf.file) != 0) {

				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

			} else

				list_add(&tf.file->f_tfile_llink,

				list_add(&tf.file->f_tfile_llink,

							&tfile_check_list);

							&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)) {

			if (is_file_epoll(tf.file)) {

				tep = tf.file->private_data;

				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)))

	    copy_from_user(&epds, event, sizeof(struct epoll_event)))

		return -EFAULT;

		return -EFAULT;





	return do_epoll_ctl(epfd, op, fd, &epds);

	return do_epoll_ctl(epfd, op, fd, &epds, false);

}

}





/*

/*

include/linux/eventpoll.h

+9 −0
Original line number Original line Diff line number Diff line
@@ -61,6 +61,15 @@ static inline void eventpoll_release(struct file *file) 
	eventpoll_release_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

#else





static inline void eventpoll_init_file(struct file *file) {}

static inline void eventpoll_init_file(struct file *file) {}