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authorHerbert Xu <herbert@gondor.apana.org.au>2006-03-21 07:43:56 +0100
committerDavid S. Miller <davem@davemloft.net>2006-03-21 07:43:56 +0100
commitcbb042f9e1292434e3cacb90e67d8d381aeac5a9 (patch)
treecc42f42232e56b68111cfebdc175197d8607bdd7 /net/core
parent[DECnet]: Use RCU locking in dn_rules.c (diff)
downloadlinux-cbb042f9e1292434e3cacb90e67d8d381aeac5a9.tar.xz
linux-cbb042f9e1292434e3cacb90e67d8d381aeac5a9.zip
[NET]: Replace skb_pull/skb_postpull_rcsum with skb_pull_rcsum
We're now starting to have quite a number of places that do skb_pull followed immediately by an skb_postpull_rcsum. We can merge these two operations into one function with skb_pull_rcsum. This makes sense since most pull operations on receive skb's need to update the checksum. I've decided to make this out-of-line since it is fairly big and the fast path where hardware checksums are enabled need to call csum_partial anyway. Since this is a brand new function we get to add an extra check on the len argument. As it is most callers of skb_pull ignore its return value which essentially means that there is no check on the len argument. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/skbuff.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 01abf1e8990b..2960c8b82b23 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1795,6 +1795,27 @@ int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
return 0;
}
+/**
+ * skb_pull_rcsum - pull skb and update receive checksum
+ * @skb: buffer to update
+ * @start: start of data before pull
+ * @len: length of data pulled
+ *
+ * This function performs an skb_pull on the packet and updates
+ * update the CHECKSUM_HW checksum. It should be used on receive
+ * path processing instead of skb_pull unless you know that the
+ * checksum difference is zero (e.g., a valid IP header) or you
+ * are setting ip_summed to CHECKSUM_NONE.
+ */
+unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
+{
+ BUG_ON(len > skb->len);
+ skb->len -= len;
+ BUG_ON(skb->len < skb->data_len);
+ skb_postpull_rcsum(skb, skb->data, len);
+ return skb->data += len;
+}
+
void __init skb_init(void)
{
skbuff_head_cache = kmem_cache_create("skbuff_head_cache",