---

yaml
---
r: 277536
b: refs/heads/master
c: b2b5ce9
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c3e072f8a6c5625028531c40ec65f7e301531be2
+refs/heads/master: b2b5ce9d1ccf1c45f8ac68e5d901112ab76ba199

trunk/include/linux/skbuff.h

@@ -540,6 +540,7 @@ extern void consume_skb(struct sk_buff *skb);
 extern void	       __kfree_skb(struct sk_buff *skb);
 extern struct sk_buff *__alloc_skb(unsigned int size,
 				   gfp_t priority, int fclone, int node);
+extern struct sk_buff *build_skb(void *data);
 static inline struct sk_buff *alloc_skb(unsigned int size,
 					gfp_t priority)
 {

trunk/net/core/skbuff.c

@@ -244,6 +244,55 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 }
 EXPORT_SYMBOL(__alloc_skb);
 
+/**
+ * build_skb - build a network buffer
+ * @data: data buffer provided by caller
+ *
+ * Allocate a new &sk_buff. Caller provides space holding head and
+ * skb_shared_info. @data must have been allocated by kmalloc()
+ * The return is the new skb buffer.
+ * On a failure the return is %NULL, and @data is not freed.
+ * Notes :
+ *  Before IO, driver allocates only data buffer where NIC put incoming frame
+ *  Driver should add room at head (NET_SKB_PAD) and
+ *  MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
+ *  After IO, driver calls build_skb(), to allocate sk_buff and populate it
+ *  before giving packet to stack.
+ *  RX rings only contains data buffers, not full skbs.
+ */
+struct sk_buff *build_skb(void *data)
+{
+	struct skb_shared_info *shinfo;
+	struct sk_buff *skb;
+	unsigned int size;
+
+	skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
+	if (!skb)
+		return NULL;
+
+	size = ksize(data) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+	memset(skb, 0, offsetof(struct sk_buff, tail));
+	skb->truesize = SKB_TRUESIZE(size);
+	atomic_set(&skb->users, 1);
+	skb->head = data;
+	skb->data = data;
+	skb_reset_tail_pointer(skb);
+	skb->end = skb->tail + size;
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+	skb->mac_header = ~0U;
+#endif
+
+	/* make sure we initialize shinfo sequentially */
+	shinfo = skb_shinfo(skb);
+	memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
+	atomic_set(&shinfo->dataref, 1);
+	kmemcheck_annotate_variable(shinfo->destructor_arg);
+
+	return skb;
+}
+EXPORT_SYMBOL(build_skb);
+
 /**
  *	__netdev_alloc_skb - allocate an skbuff for rx on a specific device
  *	@dev: network device to receive on