1 files changed, 98 insertions, 34 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 44f6a181a754..c54f3664bce5 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);