2 files changed, 41 insertions, 2 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a19ea43fea0..720b688c22b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -383,6 +383,8 @@ static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
         return __alloc_skb(size, priority, 1, -1);
 }
 
+extern int skb_recycle_check(struct sk_buff *skb, int skb_size);
+
 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
 extern struct sk_buff *skb_clone(struct sk_buff *skb,
                                  gfp_t priority);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ca1ccdf1ef7..2c218a0808b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -363,8 +363,7 @@ static void kfree_skbmem(struct sk_buff *skb)
         }
 }
 
-/* Free everything but the sk_buff shell. */
-static void skb_release_all(struct sk_buff *skb)
+static void skb_release_head_state(struct sk_buff *skb)
 {
         dst_release(skb->dst);
 #ifdef CONFIG_XFRM
@@ -388,6 +387,12 @@ static void skb_release_all(struct sk_buff *skb)
         skb->tc_verd = 0;
 #endif
 #endif
+}
+
+/* Free everything but the sk_buff shell. */
+static void skb_release_all(struct sk_buff *skb)
+{
+        skb_release_head_state(skb);
         skb_release_data(skb);
 }
 
@@ -424,6 +429,38 @@ void kfree_skb(struct sk_buff *skb)
         __kfree_skb(skb);
 }
 
+int skb_recycle_check(struct sk_buff *skb, int skb_size)
+{
+        struct skb_shared_info *shinfo;
+
+        if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
+                return 0;
+
+        skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
+        if (skb_end_pointer(skb) - skb->head < skb_size)
+                return 0;
+
+        if (skb_shared(skb) || skb_cloned(skb))
+                return 0;
+
+        skb_release_head_state(skb);
+        shinfo = skb_shinfo(skb);
+        atomic_set(&shinfo->dataref, 1);
+        shinfo->nr_frags = 0;
+        shinfo->gso_size = 0;
+        shinfo->gso_segs = 0;
+        shinfo->gso_type = 0;
+        shinfo->ip6_frag_id = 0;
+        shinfo->frag_list = NULL;
+
+        memset(skb, 0, offsetof(struct sk_buff, tail));
+        skb_reset_tail_pointer(skb);
+        skb->data = skb->head + NET_SKB_PAD;
+
+        return 1;
+}
+EXPORT_SYMBOL(skb_recycle_check);
+
 static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 {
         new->tstamp             = old->tstamp;