Revert "net: udp: fix handling of CHECKSUM_COMPLETE packets"

This reverts commit e7bbc87.

Author: popcornmix

net/core/datagram.c

@@ -807,6 +807,9 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb,
 			iov_iter_revert(&msg->msg_iter, chunk);
 			return -EINVAL;
 		}
+
+		if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
+			netdev_rx_csum_fault(skb->dev);
 	}
 	return 0;
 fault:

net/ipv4/udp.c

@@ -2124,24 +2124,8 @@ static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
 	/* Note, we are only interested in != 0 or == 0, thus the
 	 * force to int.
 	 */
-	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
-							inet_compute_pseudo);
-	if (err)
-		return err;
-
-	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
-		/* If SW calculated the value, we know it's bad */
-		if (skb->csum_complete_sw)
-			return 1;
-
-		/* HW says the value is bad. Let's validate that.
-		 * skb->csum is no longer the full packet checksum,
-		 * so don't treat it as such.
-		 */
-		skb_checksum_complete_unset(skb);
-	}
-
-	return 0;
+	return (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
+							 inet_compute_pseudo);
 }
 
 /* wrapper for udp_queue_rcv_skb tacking care of csum conversion and

net/ipv6/ip6_checksum.c

@@ -88,24 +88,8 @@ int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
 	 * Note, we are only interested in != 0 or == 0, thus the
 	 * force to int.
 	 */
-	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
-							ip6_compute_pseudo);
-	if (err)
-		return err;
-
-	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
-		/* If SW calculated the value, we know it's bad */
-		if (skb->csum_complete_sw)
-			return 1;
-
-		/* HW says the value is bad. Let's validate that.
-		 * skb->csum is no longer the full packet checksum,
-		 * so don't treat is as such.
-		 */
-		skb_checksum_complete_unset(skb);
-	}
-
-	return 0;
+	return (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
+							 ip6_compute_pseudo);
 }
 EXPORT_SYMBOL(udp6_csum_init);