From 509f87c5f564627b6b9fc763e74ef3608213d610 Mon Sep 17 00:00:00 2001 From: Dima Zavin Date: Fri, 30 Dec 2011 15:16:44 -0800 Subject: [PATCH] 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. Cc: Jeff Brown Signed-off-by: Dima Zavin Signed-off-by: Dmitry Torokhov --- drivers/input/evdev.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index a9d8716..76457d5 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -391,14 +391,13 @@ static ssize_t evdev_read(struct file *file, char __user *buffer, 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; -- 2.7.4