fs: cleanup do_pollfd

Use straightline code with failure handling gotos instead of a lot
of nested conditionals.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 23 insertions, 25 deletions

diff --git a/fs/select.c b/fs/select.c
index a87f396f0313..25da26253485 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -812,34 +812,32 @@ 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;
+        mask = DEFAULT_POLLMASK;
+        if (f.file->f_op->poll) {
+                pwait->_key = filter | busy_flag;
+                mask = f.file->f_op->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;
 }