From 716ea3a7aae3a2bfc44cb97b5419c1c9868c7bc9 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Apr 2007 20:19:53 -0700 Subject: [NET]: Move generic skbuff stuff from XFRM code to generic code Move generic skbuff stuff from XFRM code to generic code so that AF_RXRPC can use it too. The kdoc comments I've attached to the functions needs to be checked by whoever wrote them as I had to make some guesses about the workings of these functions. Signed-off-By: David Howells Signed-off-by: David S. Miller --- net/xfrm/xfrm_algo.c | 169 --------------------------------------------------- 1 file changed, 169 deletions(-) (limited to 'net/xfrm/xfrm_algo.c') diff --git a/net/xfrm/xfrm_algo.c b/net/xfrm/xfrm_algo.c index f373a8a7d9c8..6249a9405bb8 100644 --- a/net/xfrm/xfrm_algo.c +++ b/net/xfrm/xfrm_algo.c @@ -612,175 +612,6 @@ EXPORT_SYMBOL_GPL(skb_icv_walk); #if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE) -/* Looking generic it is not used in another places. */ - -int -skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) -{ - int start = skb_headlen(skb); - int i, copy = start - offset; - int elt = 0; - - if (copy > 0) { - if (copy > len) - copy = len; - sg[elt].page = virt_to_page(skb->data + offset); - sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE; - sg[elt].length = copy; - elt++; - if ((len -= copy) == 0) - return elt; - offset += copy; - } - - for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { - int end; - - BUG_TRAP(start <= offset + len); - - end = start + skb_shinfo(skb)->frags[i].size; - if ((copy = end - offset) > 0) { - skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; - - if (copy > len) - copy = len; - sg[elt].page = frag->page; - sg[elt].offset = frag->page_offset+offset-start; - sg[elt].length = copy; - elt++; - if (!(len -= copy)) - return elt; - 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); - - end = start + list->len; - if ((copy = end - offset) > 0) { - if (copy > len) - copy = len; - elt += skb_to_sgvec(list, sg+elt, offset - start, copy); - if ((len -= copy) == 0) - return elt; - offset += copy; - } - start = end; - } - } - BUG_ON(len); - return elt; -} -EXPORT_SYMBOL_GPL(skb_to_sgvec); - -/* Check that skb data bits are writable. If they are not, copy data - * to newly created private area. If "tailbits" is given, make sure that - * tailbits bytes beyond current end of skb are writable. - * - * Returns amount of elements of scatterlist to load for subsequent - * transformations and pointer to writable trailer skb. - */ - -int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) -{ - int copyflag; - int elt; - struct sk_buff *skb1, **skb_p; - - /* If skb is cloned or its head is paged, reallocate - * head pulling out all the pages (pages are considered not writable - * at the moment even if they are anonymous). - */ - if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) && - __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL) - return -ENOMEM; - - /* Easy case. Most of packets will go this way. */ - if (!skb_shinfo(skb)->frag_list) { - /* A little of trouble, not enough of space for trailer. - * This should not happen, when stack is tuned to generate - * good frames. OK, on miss we reallocate and reserve even more - * space, 128 bytes is fair. */ - - if (skb_tailroom(skb) < tailbits && - pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC)) - return -ENOMEM; - - /* Voila! */ - *trailer = skb; - return 1; - } - - /* Misery. We are in troubles, going to mincer fragments... */ - - elt = 1; - skb_p = &skb_shinfo(skb)->frag_list; - copyflag = 0; - - while ((skb1 = *skb_p) != NULL) { - int ntail = 0; - - /* The fragment is partially pulled by someone, - * this can happen on input. Copy it and everything - * after it. */ - - if (skb_shared(skb1)) - copyflag = 1; - - /* If the skb is the last, worry about trailer. */ - - if (skb1->next == NULL && tailbits) { - if (skb_shinfo(skb1)->nr_frags || - skb_shinfo(skb1)->frag_list || - skb_tailroom(skb1) < tailbits) - ntail = tailbits + 128; - } - - if (copyflag || - skb_cloned(skb1) || - ntail || - skb_shinfo(skb1)->nr_frags || - skb_shinfo(skb1)->frag_list) { - struct sk_buff *skb2; - - /* Fuck, we are miserable poor guys... */ - if (ntail == 0) - skb2 = skb_copy(skb1, GFP_ATOMIC); - else - skb2 = skb_copy_expand(skb1, - skb_headroom(skb1), - ntail, - GFP_ATOMIC); - if (unlikely(skb2 == NULL)) - return -ENOMEM; - - if (skb1->sk) - skb_set_owner_w(skb2, skb1->sk); - - /* Looking around. Are we still alive? - * OK, link new skb, drop old one */ - - skb2->next = skb1->next; - *skb_p = skb2; - kfree_skb(skb1); - skb1 = skb2; - } - elt++; - *trailer = skb1; - skb_p = &skb1->next; - } - - return elt; -} -EXPORT_SYMBOL_GPL(skb_cow_data); - void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len) { if (tail != skb) { -- cgit v1.2.3 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 6249a9405bb8..be529c4241a6 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 From 1a028e50729b85d0a038fad13daf0ee201a37454 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 27 Apr 2007 15:21:23 -0700 Subject: [NET]: Revert sk_buff walker cleanups. This reverts eefa3906283a2b60a6d02a2cda593a7d7d7946c5 The simplification made in that change works with the assumption that the 'offset' parameter to these functions is always positive or zero, which is not true. It can be and often is negative in order to access SKB header values in front of skb->data. Signed-off-by: David S. Miller --- net/xfrm/xfrm_algo.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) (limited to 'net/xfrm/xfrm_algo.c') diff --git a/net/xfrm/xfrm_algo.c b/net/xfrm/xfrm_algo.c index be529c4241a6..6249a9405bb8 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 end = skb_headlen(skb); - int i, copy = end - offset; + int start = skb_headlen(skb); + int i, copy = start - offset; int err; struct scatterlist sg; @@ -556,9 +556,11 @@ int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, } for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { - BUG_TRAP(len >= 0); + int end; - end = offset + skb_shinfo(skb)->frags[i].size; + BUG_TRAP(start <= offset + len); + + end = start + skb_shinfo(skb)->frags[i].size; if ((copy = end - offset) > 0) { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; @@ -566,7 +568,7 @@ int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc, copy = len; sg.page = frag->page; - sg.offset = frag->page_offset; + sg.offset = frag->page_offset + offset-start; sg.length = copy; err = icv_update(desc, &sg, copy); @@ -577,19 +579,22 @@ 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) { - BUG_TRAP(len >= 0); + int end; + + BUG_TRAP(start <= offset + len); - end = offset + list->len; + end = start + list->len; if ((copy = end - offset) > 0) { if (copy > len) copy = len; - err = skb_icv_walk(list, desc, 0, + err = skb_icv_walk(list, desc, offset-start, copy, icv_update); if (unlikely(err)) return err; @@ -597,6 +602,7 @@ 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