1 files changed, 98 insertions, 34 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 44f6a181a7545..c54f3664bce5b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -71,13 +71,6 @@ static kmem_cache_t *skbuff_head_cache __read_mostly;
 static kmem_cache_t *skbuff_fclone_cache __read_mostly;
 
 /*
- * lockdep: lock class key used by skb_queue_head_init():
- */
-struct lock_class_key skb_queue_lock_key;
-
-EXPORT_SYMBOL(skb_queue_lock_key);
-
-/*
  *	Keep out-of-line to prevent kernel bloat.
  *	__builtin_return_address is not used because it is not always
  *	reliable.
@@ -256,12 +249,37 @@ nodata:
 	goto out;
 }
 
+/**
+ *	__netdev_alloc_skb - allocate an skbuff for rx on a specific device
+ *	@dev: network device to receive on
+ *	@length: length to allocate
+ *	@gfp_mask: get_free_pages mask, passed to alloc_skb
+ *
+ *	Allocate a new &sk_buff and assign it a usage count of one. The
+ *	buffer has unspecified headroom built in. Users should allocate
+ *	the headroom they think they need without accounting for the
+ *	built in space. The built in space is used for optimisations.
+ *
+ *	%NULL is returned if there is no free memory.
+ */
+struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
+		unsigned int length, gfp_t gfp_mask)
+{
+	struct sk_buff *skb;
 
-static void skb_drop_fraglist(struct sk_buff *skb)
+	skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
+	if (likely(skb)) {
+		skb_reserve(skb, NET_SKB_PAD);
+		skb->dev = dev;
+	}
+	return skb;
+}
+
+static void skb_drop_list(struct sk_buff **listp)
 {
-	struct sk_buff *list = skb_shinfo(skb)->frag_list;
+	struct sk_buff *list = *listp;
 
-	skb_shinfo(skb)->frag_list = NULL;
+	*listp = NULL;
 
 	do {
 		struct sk_buff *this = list;
@@ -270,6 +288,11 @@ static void skb_drop_fraglist(struct sk_buff *skb)
 	} while (list);
 }
 
+static inline void skb_drop_fraglist(struct sk_buff *skb)
+{
+	skb_drop_list(&skb_shinfo(skb)->frag_list);
+}
+
 static void skb_clone_fraglist(struct sk_buff *skb)
 {
 	struct sk_buff *list;
@@ -830,41 +853,81 @@ free_skb:
 
 int ___pskb_trim(struct sk_buff *skb, unsigned int len)
 {
+	struct sk_buff **fragp;
+	struct sk_buff *frag;
 	int offset = skb_headlen(skb);
 	int nfrags = skb_shinfo(skb)->nr_frags;
 	int i;
+	int err;
 
-	for (i = 0; i < nfrags; i++) {
+	if (skb_cloned(skb) &&
+	    unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
+		return err;
+
+	i = 0;
+	if (offset >= len)
+		goto drop_pages;
+
+	for (; i < nfrags; i++) {
 		int end = offset + skb_shinfo(skb)->frags[i].size;
-		if (end > len) {
-			if (skb_cloned(skb)) {
-				if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
-					return -ENOMEM;
-			}
-			if (len <= offset) {
-				put_page(skb_shinfo(skb)->frags[i].page);
-				skb_shinfo(skb)->nr_frags--;
-			} else {
-				skb_shinfo(skb)->frags[i].size = len - offset;
-			}
+
+		if (end < len) {
+			offset = end;
+			continue;
 		}
-		offset = end;
+
+		skb_shinfo(skb)->frags[i++].size = len - offset;
+
+drop_pages:
+		skb_shinfo(skb)->nr_frags = i;
+
+		for (; i < nfrags; i++)
+			put_page(skb_shinfo(skb)->frags[i].page);
+
+		if (skb_shinfo(skb)->frag_list)
+			skb_drop_fraglist(skb);
+		goto done;
 	}
 
-	if (offset < len) {
+	for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
+	     fragp = &frag->next) {
+		int end = offset + frag->len;
+
+		if (skb_shared(frag)) {
+			struct sk_buff *nfrag;
+
+			nfrag = skb_clone(frag, GFP_ATOMIC);
+			if (unlikely(!nfrag))
+				return -ENOMEM;
+
+			nfrag->next = frag->next;
+			kfree_skb(frag);
+			frag = nfrag;
+			*fragp = frag;
+		}
+
+		if (end < len) {
+			offset = end;
+			continue;
+		}
+
+		if (end > len &&
+		    unlikely((err = pskb_trim(frag, len - offset))))
+			return err;
+
+		if (frag->next)
+			skb_drop_list(&frag->next);
+		break;
+	}
+
+done:
+	if (len > skb_headlen(skb)) {
 		skb->data_len -= skb->len - len;
 		skb->len       = len;
 	} else {
-		if (len <= skb_headlen(skb)) {
-			skb->len      = len;
-			skb->data_len = 0;
-			skb->tail     = skb->data + len;
-			if (skb_shinfo(skb)->frag_list && !skb_cloned(skb))
-				skb_drop_fraglist(skb);
-		} else {
-			skb->data_len -= skb->len - len;
-			skb->len       = len;
-		}
+		skb->len       = len;
+		skb->data_len  = 0;
+		skb->tail      = skb->data + len;
 	}
 
 	return 0;
@@ -2003,6 +2066,7 @@ EXPORT_SYMBOL(__kfree_skb);
 EXPORT_SYMBOL(kfree_skb);
 EXPORT_SYMBOL(__pskb_pull_tail);
 EXPORT_SYMBOL(__alloc_skb);
+EXPORT_SYMBOL(__netdev_alloc_skb);
 EXPORT_SYMBOL(pskb_copy);
 EXPORT_SYMBOL(pskb_expand_head);
 EXPORT_SYMBOL(skb_checksum);