From 7ce5a27f2ef8ed4f8f892f46391f933c0e2ac0f1 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 2 Dec 2013 17:26:05 -0500 Subject: [PATCH] Revert "net: Handle CHECKSUM_COMPLETE more adequately in pskb_trim_rcsum()." This reverts commit 018c5bba052b3a383d83cf0c756da0e7bc748397. It causes regressions for people using chips driven by the sungem driver. Suspicion is that the skb->csum value isn't being adjusted properly. The change also has a bug in that if __pskb_trim() fails, we'll leave a corruped skb->csum value in there. We would really need to revert it to it's original value in that case. Signed-off-by: David S. Miller --- include/linux/skbuff.h | 39 ++++++++++++++++++--------------------- 1 file changed, 18 insertions(+), 21 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index bec1cc7d5e3c..215b5ea1cb30 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2263,6 +2263,24 @@ static inline void skb_postpull_rcsum(struct sk_buff *skb, unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len); +/** + * pskb_trim_rcsum - trim received skb and update checksum + * @skb: buffer to trim + * @len: new length + * + * This is exactly the same as pskb_trim except that it ensures the + * checksum of received packets are still valid after the operation. + */ + +static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) +{ + if (likely(len >= skb->len)) + return 0; + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + return __pskb_trim(skb, len); +} + #define skb_queue_walk(queue, skb) \ for (skb = (queue)->next; \ skb != (struct sk_buff *)(queue); \ @@ -2360,27 +2378,6 @@ __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len, __wsum skb_checksum(const struct sk_buff *skb, int offset, int len, __wsum csum); -/** - * pskb_trim_rcsum - trim received skb and update checksum - * @skb: buffer to trim - * @len: new length - * - * This is exactly the same as pskb_trim except that it ensures the - * checksum of received packets are still valid after the operation. - */ - -static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) -{ - if (likely(len >= skb->len)) - return 0; - if (skb->ip_summed == CHECKSUM_COMPLETE) { - __wsum adj = skb_checksum(skb, len, skb->len - len, 0); - - skb->csum = csum_sub(skb->csum, adj); - } - return __pskb_trim(skb, len); -} - static inline void *skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer) { -- 2.20.1