[PATCH 02/18] icmp_push_reply(): reorder adding the checksum up

From: Al Viro
Date: Tue Jul 21 2020 - 16:26:41 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

do csum_partial_copy_nocheck() on the first fragment, then
add the rest to it. Equivalent transformation.

That was the only caller of csum_partial_copy_nocheck() that
might pass it non-zero as the last argument.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
net/ipv4/icmp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 62d7a2bfc9a3..f93317157549 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -376,15 +376,15 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
ip_flush_pending_frames(sk);
} else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
struct icmphdr *icmph = icmp_hdr(skb);
- __wsum csum = 0;
+ __wsum csum;
struct sk_buff *skb1;

+ csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
+ (char *)icmph,
+ icmp_param->head_len, 0);
skb_queue_walk(&sk->sk_write_queue, skb1) {
csum = csum_add(csum, skb1->csum);
}
- csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
- (char *)icmph,
- icmp_param->head_len, csum);
icmph->checksum = csum_fold(csum);
skb->ip_summed = CHECKSUM_NONE;
ip_push_pending_frames(sk, fl4);
--
2.11.0