[PATCH] ISDN: fix copy_to_user() unused result warning in isdn_ppp

   drivers/isdn/i4l/isdn_ppp.c:785: warning: ignoring return value of `copy_to_user', declared with attribute warn_unused_result
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/isdn/i4l/isdn_ppp.c

@@ -782,7 +782,8 @@ isdn_ppp_read(int min, struct file *file, char __user *buf, int count)
 	is->first = b;
 
 	spin_unlock_irqrestore(&is->buflock, flags);
-	copy_to_user(buf, save_buf, count);
+	if (copy_to_user(buf, save_buf, count))
+		count = -EFAULT;
 	kfree(save_buf);
 
 	return count;