input: evdev: do not block waiting for an event if fd is nonblock
If there is a full packet in the buffer, and we overflow that buffer
right after checking for that condition, it would have been possible
for us to block indefinitely (rather, until the next full packet) even if
the file was marked as O_NONBLOCK.
Change-Id: Icd0f59f8cc98392be4c4d13bd45b5cf94317eb5a
Signed-off-by: Dima Zavin <dima@android.com>
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 10ae1c9..5c5f9db 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -405,14 +405,12 @@
if (count < input_event_size())
return -EINVAL;
- if (client->packet_head == client->tail && evdev->exist &&
- (file->f_flags & O_NONBLOCK))
- return -EAGAIN;
-
- retval = wait_event_interruptible(evdev->wait,
- client->packet_head != client->tail || !evdev->exist);
- if (retval)
- return retval;
+ if (!(file->f_flags & O_NONBLOCK)) {
+ retval = wait_event_interruptible(evdev->wait,
+ client->packet_head != client->tail || !evdev->exist);
+ if (retval)
+ return retval;
+ }
if (!evdev->exist)
return -ENODEV;