From eefa3906283a2b60a6d02a2cda593a7d7d7946c5 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 26 Apr 2007 00:44:22 -0700 Subject: [NET]: Clean up sk_buff walkers. I noticed recently that, in skb_checksum(), "offset" and "start" are essentially the same thing and have the same value throughout the function, despite being computed differently. Using a single variable allows some cleanups and makes the skb_checksum() function smaller, more readable, and presumably marginally faster. We appear to have many other "sk_buff walker" functions built on the exact same model, so the cleanup applies to them, too. Here is a list of the functions I found to be affected: net/appletalk/ddp.c:atalk_sum_skb() net/core/datagram.c:skb_copy_datagram_iovec() net/core/datagram.c:skb_copy_and_csum_datagram() net/core/skbuff.c:skb_copy_bits() net/core/skbuff.c:skb_store_bits() net/core/skbuff.c:skb_checksum() net/core/skbuff.c:skb_copy_and_csum_bit() net/core/user_dma.c:dma_skb_copy_datagram_iovec() net/xfrm/xfrm_algo.c:skb_icv_walk() net/xfrm/xfrm_algo.c:skb_to_sgvec() OTOH, I admit I'm a bit surprised, the cleanup is rather obvious so I'm really wondering if I am missing something. Can anyone please comment on this? Signed-off-by: Jean Delvare Signed-off-by: David S. Miller --- net/xfrm/xfrm_algo.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) (limited to 'net/xfrm/xfrm_algo.c') diff --git a/net/xfrm/xfrm_algo.c b/net/xfrm/xfrm_algo.c index 6249a9405bb..be529c4241a 100644 --- a/net/xfrm/xfrm_algo.c +++ b/net/xfrm/xfrm_algo.c @@ -532,8 +532,8 @@ EXPORT_SYMBOL_GPL(xfrm_count_enc_supported); int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, int offset, int len, icv_update_fn_t icv_update) { - int start = skb_headlen(skb); - int i, copy = start - offset; + int end = skb_headlen(skb); + int i, copy = end - offset; int err; struct scatterlist sg; @@ -556,11 +556,9 @@ int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, } for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { - int end; + BUG_TRAP(len >= 0); - BUG_TRAP(start <= offset + len); - - end = start + skb_shinfo(skb)->frags[i].size; + end = offset + skb_shinfo(skb)->frags[i].size; if ((copy = end - offset) > 0) { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; @@ -568,7 +566,7 @@ int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, copy = len; sg.page = frag->page; - sg.offset = frag->page_offset + offset-start; + sg.offset = frag->page_offset; sg.length = copy; err = icv_update(desc, &sg, copy); @@ -579,22 +577,19 @@ int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, return 0; offset += copy; } - start = end; } if (skb_shinfo(skb)->frag_list) { struct sk_buff *list = skb_shinfo(skb)->frag_list; for (; list; list = list->next) { - int end; - - BUG_TRAP(start <= offset + len); + BUG_TRAP(len >= 0); - end = start + list->len; + end = offset + list->len; if ((copy = end - offset) > 0) { if (copy > len) copy = len; - err = skb_icv_walk(list, desc, offset-start, + err = skb_icv_walk(list, desc, 0, copy, icv_update); if (unlikely(err)) return err; @@ -602,7 +597,6 @@ int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, return 0; offset += copy; } - start = end; } } BUG_ON(len); -- cgit v1.2.3-70-g09d2