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authorDima Zavin <dima@android.com>2011-12-30 15:16:44 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2011-12-30 15:26:35 -0800
commit509f87c5f564627b6b9fc763e74ef3608213d610 (patch)
treec5034b38b7c49d75726ed24411a4bd9c57bc1f73 /drivers/input
parente90f869cae3b4aedf0f6d2ca8048d60245ee77f7 (diff)
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>
Diffstat (limited to 'drivers/input')
-rw-r--r--drivers/input/evdev.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index a9d871651ce..76457d50bc3 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;