batman-adv: Directly check read of icmp packet in copy_from_user

The access_ok read check can be directly done in copy_from_user since a failure
of access_ok is handled the same way as an error in __copy_from_user.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

net/batman-adv/icmp_socket.c

@@ -187,12 +187,7 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
 	skb_reserve(skb, sizeof(struct ethhdr));
 	icmp_packet = (struct icmp_packet_rr *)skb_put(skb, packet_len);
 
-	if (!access_ok(VERIFY_READ, buff, packet_len)) {
-		len = -EFAULT;
-		goto free_skb;
-	}
-
-	if (__copy_from_user(icmp_packet, buff, packet_len)) {
+	if (copy_from_user(icmp_packet, buff, packet_len)) {
 		len = -EFAULT;
 		goto free_skb;
 	}