Commit 509f87c5 authored Dec 30, 2011 by Dima Zavin Committed by Dmitry Torokhov Dec 30, 2011

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 <jeffbrown@android.com>
Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

parent e90f869c

drivers/input/evdev.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -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;

		if (!(file->f_flags & O_NONBLOCK)) {
		retval = wait_event_interruptible(evdev->wait,
		client->packet_head != client->tail \|\| !evdev->exist);
		client->packet_head != client->tail \|\|
		!evdev->exist);
		if (retval)
		return retval;
		}

		if (!evdev->exist)
		return -ENODEV;

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