From 27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 19 Apr 2007 20:29:13 -0700 Subject: [SK_BUFF]: Convert skb->tail to sk_buff_data_t So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes on 64bit architectures, allowing us to combine the 4 bytes hole left by the layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4 64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN... :-) Many calculations that previously required that skb->{transport,network, mac}_header be first converted to a pointer now can be done directly, being meaningful as offsets or pointers. Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- net/core/skbuff.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) (limited to 'net/core/skbuff.c') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a48b0868126..ddcbc4d10da 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -87,8 +87,9 @@ static struct kmem_cache *skbuff_fclone_cache __read_mostly; void skb_over_panic(struct sk_buff *skb, int sz, void *here) { printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " - "data:%p tail:%p end:%p dev:%s\n", - here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, + "data:%p tail:%#lx end:%p dev:%s\n", + here, skb->len, sz, skb->head, skb->data, + (unsigned long)skb->tail, skb->end, skb->dev ? skb->dev->name : ""); BUG(); } @@ -105,8 +106,9 @@ void skb_over_panic(struct sk_buff *skb, int sz, void *here) void skb_under_panic(struct sk_buff *skb, int sz, void *here) { printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " - "data:%p tail:%p end:%p dev:%s\n", - here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, + "data:%p tail:%#lx end:%p dev:%s\n", + here, skb->len, sz, skb->head, skb->data, + (unsigned long)skb->tail, skb->end, skb->dev ? skb->dev->name : ""); BUG(); } @@ -167,7 +169,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, atomic_set(&skb->users, 1); skb->head = data; skb->data = data; - skb->tail = data; + skb_reset_tail_pointer(skb); skb->end = data + size; /* make sure we initialize shinfo sequentially */ shinfo = skb_shinfo(skb); @@ -629,7 +631,12 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, /* Copy only real data... and, alas, header. This should be * optimized for the cases when header is void. */ - memcpy(data + nhead, skb->head, skb->tail - skb->head); + memcpy(data + nhead, skb->head, + skb->tail +#ifndef NET_SKBUFF_DATA_USES_OFFSET + - skb->head +#endif + ); memcpy(data + size, skb->end, sizeof(struct skb_shared_info)); for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) @@ -645,9 +652,9 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, skb->head = data; skb->end = data + size; skb->data += off; - skb->tail += off; #ifndef NET_SKBUFF_DATA_USES_OFFSET - /* {transport,network,mac}_header are relative to skb->head */ + /* {transport,network,mac}_header and tail are relative to skb->head */ + skb->tail += off; skb->transport_header += off; skb->network_header += off; skb->mac_header += off; @@ -762,7 +769,7 @@ int skb_pad(struct sk_buff *skb, int pad) return 0; } - ntail = skb->data_len + pad - (skb->end - skb->tail); + ntail = skb->data_len + pad - (skb->end - skb_tail_pointer(skb)); if (likely(skb_cloned(skb) || ntail > 0)) { err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); if (unlikely(err)) @@ -863,7 +870,7 @@ done: } else { skb->len = len; skb->data_len = 0; - skb->tail = skb->data + len; + skb_set_tail_pointer(skb, len); } return 0; @@ -900,7 +907,7 @@ unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) * plus 128 bytes for future expansions. If we have enough * room at tail, reallocate without expansion only if skb is cloned. */ - int i, k, eat = (skb->tail + delta) - skb->end; + int i, k, eat = (skb_tail_pointer(skb) + delta) - skb->end; if (eat > 0 || skb_cloned(skb)) { if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, @@ -908,7 +915,7 @@ unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) return NULL; } - if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta)) + if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta)) BUG(); /* Optimization: no fragments, no reasons to preestimate @@ -1004,7 +1011,7 @@ pull_pages: skb->tail += delta; skb->data_len -= delta; - return skb->tail; + return skb_tail_pointer(skb); } /* Copy some data bits from skb to kernel buffer. */ @@ -1539,7 +1546,7 @@ static inline void skb_split_inside_header(struct sk_buff *skb, skb1->len += skb1->data_len; skb->data_len = 0; skb->len = len; - skb->tail = skb->data + len; + skb_set_tail_pointer(skb, len); } static inline void skb_split_no_header(struct sk_buff *skb, -- cgit v1.2.3