net: packet split receive api

Add some packet-split receive hooks.

For one this allows to do NUMA node affine page allocs. Later on these
hooks will be extended to do emergency reserve allocations for
fragments.

Signed-off-by: Peter Zijlstra <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/skbuff.h

···
 	skb_shinfo(skb)->nr_frags = i + 1;
 }
 
+extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
+			    int off, int size);
+
 #define SKB_PAGE_ASSERT(skb) 	BUG_ON(skb_shinfo(skb)->nr_frags)
 #define SKB_FRAG_ASSERT(skb) 	BUG_ON(skb_shinfo(skb)->frag_list)
 #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
···
 		unsigned int length)
 {
 	return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
+}
+
+extern struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask);
+
+/**
+ *	netdev_alloc_page - allocate a page for ps-rx on a specific device
+ *	@dev: network device to receive on
+ *
+ * 	Allocate a new page node local to the specified device.
+ *
+ * 	%NULL is returned if there is no free memory.
+ */
+static inline struct page *netdev_alloc_page(struct net_device *dev)
+{
+	return __netdev_alloc_page(dev, GFP_ATOMIC);
+}
+
+static inline void netdev_free_page(struct net_device *dev, struct page *page)
+{
+	__free_page(page);
 }
 
 /**

net/core/skbuff.c

···
 	return skb;
 }
 
+struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask)
+{
+	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
+	struct page *page;
+
+	page = alloc_pages_node(node, gfp_mask, 0);
+	return page;
+}
+EXPORT_SYMBOL(__netdev_alloc_page);
+
+void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
+		int size)
+{
+	skb_fill_page_desc(skb, i, page, off, size);
+	skb->len += size;
+	skb->data_len += size;
+	skb->truesize += size;
+}
+EXPORT_SYMBOL(skb_add_rx_frag);
+
 /**
  *	dev_alloc_skb - allocate an skbuff for receiving
  *	@length: length to allocate