From e9fa4f7bd291c29a785666e2fa5a9cf3241ee6c3 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 13 Aug 2006 20:12:58 -0700 Subject: [PATCH] [INET]: Use pskb_trim_unique when trimming paged unique skbs The IPv4/IPv6 datagram output path was using skb_trim to trim paged packets because they know that the packet has not been cloned yet (since the packet hasn't been given to anything else in the system). This broke because skb_trim no longer allows paged packets to be trimmed. Paged packets must be given to one of the pskb_trim functions instead. This patch adds a new pskb_trim_unique function to cover the IPv4/IPv6 datagram output path scenario and replaces the corresponding skb_trim calls with it. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/linux/skbuff.h | 15 +++++++++++++++ net/ipv4/ip_output.c | 4 ++-- net/ipv6/ip6_output.c | 2 +- 3 files changed, 18 insertions(+), 3 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 3573ba9a25..755e9cddac 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1039,6 +1039,21 @@ static inline int pskb_trim(struct sk_buff *skb, unsigned int len) return (len < skb->len) ? __pskb_trim(skb, len) : 0; } +/** + * pskb_trim_unique - remove end from a paged unique (not cloned) buffer + * @skb: buffer to alter + * @len: new length + * + * This is identical to pskb_trim except that the caller knows that + * the skb is not cloned so we should never get an error due to out- + * of-memory. + */ +static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len) +{ + int err = pskb_trim(skb, len); + BUG_ON(err); +} + /** * skb_orphan - orphan a buffer * @skb: buffer to orphan diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 9bf307a297..4c20f55468 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -947,7 +947,7 @@ alloc_new_skb: skb_prev->csum = csum_sub(skb_prev->csum, skb->csum); data += fraggap; - skb_trim(skb_prev, maxfraglen); + pskb_trim_unique(skb_prev, maxfraglen); } copy = datalen - transhdrlen - fraggap; @@ -1142,7 +1142,7 @@ ssize_t ip_append_page(struct sock *sk, struct page *page, data, fraggap, 0); skb_prev->csum = csum_sub(skb_prev->csum, skb->csum); - skb_trim(skb_prev, maxfraglen); + pskb_trim_unique(skb_prev, maxfraglen); } /* diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 69451af6ab..4fb47a2529 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1095,7 +1095,7 @@ alloc_new_skb: skb_prev->csum = csum_sub(skb_prev->csum, skb->csum); data += fraggap; - skb_trim(skb_prev, maxfraglen); + pskb_trim_unique(skb_prev, maxfraglen); } copy = datalen - transhdrlen - fraggap; if (copy < 0) { -- 2.39.5