1 files changed, 49 insertions, 36 deletions

diff --git a/fs/select.c b/fs/select.c
index ba879c51288f..bc3cc0f98896 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -34,6 +34,29 @@
 
 #include <linux/uaccess.h>
 
+__poll_t vfs_poll(struct file *file, struct poll_table_struct *pt)
+{
+	if (file->f_op->poll) {
+		return file->f_op->poll(file, pt);
+	} else if (file_has_poll_mask(file)) {
+		unsigned int events = poll_requested_events(pt);
+		struct wait_queue_head *head;
+
+		if (pt && pt->_qproc) {
+			head = file->f_op->get_poll_head(file, events);
+			if (!head)
+				return DEFAULT_POLLMASK;
+			if (IS_ERR(head))
+				return EPOLLERR;
+			pt->_qproc(file, head, pt);
+		}
+
+		return file->f_op->poll_mask(file, events);
+	} else {
+		return DEFAULT_POLLMASK;
+	}
+}
+EXPORT_SYMBOL_GPL(vfs_poll);
 
 /*
  * Estimate expected accuracy in ns from a timeval.
@@ -233,7 +256,7 @@ static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
 	add_wait_queue(wait_address, &entry->wait);
 }
 
-int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
+static int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
 			  ktime_t *expires, unsigned long slack)
 {
 	int rc = -EINTR;
@@ -258,7 +281,6 @@ int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
 
 	return rc;
 }
-EXPORT_SYMBOL(poll_schedule_timeout);
 
 /**
  * poll_select_set_timeout - helper function to setup the timeout value
@@ -503,14 +525,10 @@ static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
 					continue;
 				f = fdget(i);
 				if (f.file) {
-					const struct file_operations *f_op;
-					f_op = f.file->f_op;
-					mask = DEFAULT_POLLMASK;
-					if (f_op->poll) {
-						wait_key_set(wait, in, out,
-							     bit, busy_flag);
-						mask = (*f_op->poll)(f.file, wait);
-					}
+					wait_key_set(wait, in, out, bit,
+						     busy_flag);
+					mask = vfs_poll(f.file, wait);
+
 					fdput(f);
 					if ((mask & POLLIN_SET) && (in & bit)) {
 						res_in |= bit;
@@ -813,34 +831,29 @@ static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait,
 				     bool *can_busy_poll,
 				     __poll_t busy_flag)
 {
-	__poll_t mask;
-	int fd;
-
-	mask = 0;
-	fd = pollfd->fd;
-	if (fd >= 0) {
-		struct fd f = fdget(fd);
-		mask = EPOLLNVAL;
-		if (f.file) {
-			/* userland u16 ->events contains POLL... bitmap */
-			__poll_t filter = demangle_poll(pollfd->events) |
-						EPOLLERR | EPOLLHUP;
-			mask = DEFAULT_POLLMASK;
-			if (f.file->f_op->poll) {
-				pwait->_key = filter;
-				pwait->_key |= busy_flag;
-				mask = f.file->f_op->poll(f.file, pwait);
-				if (mask & busy_flag)
-					*can_busy_poll = true;
-			}
-			/* Mask out unneeded events. */
-			mask &= filter;
-			fdput(f);
-		}
-	}
+	int fd = pollfd->fd;
+	__poll_t mask = 0, filter;
+	struct fd f;
+
+	if (fd < 0)
+		goto out;
+	mask = EPOLLNVAL;
+	f = fdget(fd);
+	if (!f.file)
+		goto out;
+
+	/* userland u16 ->events contains POLL... bitmap */
+	filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
+	pwait->_key = filter | busy_flag;
+	mask = vfs_poll(f.file, pwait);
+	if (mask & busy_flag)
+		*can_busy_poll = true;
+	mask &= filter;		/* Mask out unneeded events. */
+	fdput(f);
+
+out:
 	/* ... and so does ->revents */
 	pollfd->revents = mangle_poll(mask);
-
 	return mask;
 }