eventpoll: support non-blocking do_epoll_ctl() calls (39220e8d) · Commits · 戴 / test

fs/eventpoll.c

+33 −13

Original line number	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;
		}

		/* 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);
		}

		/*

include/linux/eventpoll.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -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) {}

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