From 13f19624029f43f5d0f98a96a9e6ba4d38da96a9 Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Wed, 28 Nov 2012 00:10:44 +0100 Subject: [PATCH 1/1] HID: hiddev: fix nonblocking read semantics wrt EIO/ERESTARTSYS When the file has been open in non-blocking mode, EIO or ERESTARTSYS would never be returned even if they should (for example when device has been unplugged, you want EIO and not EAGAIN to be returned). Move the O_NONBLOCK check after other checks have been performed. Base on similar patch done to hidraw by Founder Fang Signed-off-by: Jiri Kosina --- drivers/hid/usbhid/hiddev.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c index 711c9656ec0f..87bd64959a91 100644 --- a/drivers/hid/usbhid/hiddev.c +++ b/drivers/hid/usbhid/hiddev.c @@ -361,10 +361,6 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE); while (list->head == list->tail) { - if (file->f_flags & O_NONBLOCK) { - retval = -EAGAIN; - break; - } if (signal_pending(current)) { retval = -ERESTARTSYS; break; @@ -373,6 +369,10 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun retval = -EIO; break; } + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } /* let O_NONBLOCK tasks run */ mutex_unlock(&list->thread_lock); -- 2.39.2