Staging: comedi: fix signal handling in read and write

commit 6a9ce6b6 upstream.

After sleeping on a wait queue, signal_pending(current) should be
checked (not before sleeping).
Acked-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/comedi_fops.c

@@ -1673,11 +1673,11 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
 				retval = -EAGAIN;
 				break;
 			}
+			schedule();
 			if (signal_pending(current)) {
 				retval = -ERESTARTSYS;
 				break;
 			}
-			schedule();
 			if (!s->busy)
 				break;
 			if (s->busy != file) {
@@ -1780,11 +1780,11 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 				retval = -EAGAIN;
 				break;
 			}
+			schedule();
 			if (signal_pending(current)) {
 				retval = -ERESTARTSYS;
 				break;
 			}
-			schedule();
 			if (!s->busy) {
 				retval = 0;
 				break;