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HID: hidraw: fix nonblock read return EAGAIN after device removed

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When nonblock read the condition check (file->f_flags & O_NONBLOCK) always be
true, signal_pending and device exist checking never get a chance to run, so
the user mode code always get EAGAIN even if device removed. move nonblock mode
checking to the last can fix this problem.

Signed-off-by: Founder Fang <founder.fang@gmail.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Founder Fang 2012-11-21 15:20:31 +08:00 committed by Jiri Kosina
parent 1a1e8c6fad
commit 7611e8d26d
1 changed files with 4 additions and 4 deletions
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8
drivers/hid/hidraw.c
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@ -57,10 +57,6 @@ static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count,
set_current_state(TASK_INTERRUPTIBLE);
while (list->head == list->tail) {
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
@ -69,6 +65,10 @@ static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count,
ret = -EIO;
break;
}
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
/* allow O_NONBLOCK to work well from other threads */
mutex_unlock(&list->read_mutex);