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HID: hiddev: fix nonblocking read semantics wrt EIO/ERESTARTSYS

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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 <founder.fang@gmail.com>

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Jiri Kosina 2012-11-28 00:10:44 +01:00
parent 4cc8541782
commit 13f1962402
1 changed files with 4 additions and 4 deletions
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8
drivers/hid/usbhid/hiddev.c
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@ -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); prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
while (list->head == list->tail) { while (list->head == list->tail) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
break;
}
if (signal_pending(current)) { if (signal_pending(current)) {
retval = -ERESTARTSYS; retval = -ERESTARTSYS;
break; break;
@ -373,6 +369,10 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
retval = -EIO; retval = -EIO;
break; break;
} }
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
break;
}
/* let O_NONBLOCK tasks run */ /* let O_NONBLOCK tasks run */
mutex_unlock(&list->thread_lock); mutex_unlock(&list->thread_lock);