Merge branch 'netdev_page_frags'

Alexander Duyck says:

====================
Refactor netdev page frags and move them into mm/

This patch series addresses several things.

First I found an issue in the performance of the pfmemalloc check from
build_skb.  To work around it I have provided a cached copy of pfmemalloc
to be used in __netdev_alloc_skb and __napi_alloc_skb.

Second I moved the page fragment allocation logic into the mm tree and
added functionality for freeing page fragments.  I had to fix igb before I
could do this as it was using a reference to NETDEV_FRAG_PAGE_MAX_SIZE
incorrectly.

Finally I went through and replaced all of the duplicate code that was
calling put_page and replaced it with calls to skb_free_frag.

With these changes in place a simple receive and drop test increased from a
packet rate of 8.9Mpps to 9.8Mpps.  The gains breakdown as follows:

8.9Mpps	Before			9.8Mpps	After
------------------------	------------------------
7.8%	put_compound_page	9.1%	__free_page_frag
3.9%	skb_free_head
1.1%	put_page

4.9%	build_skb		3.8%	__napi_alloc_skb
2.5%	__alloc_rx_skb
1.9%	__napi_alloc_skb
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

@@ -662,7 +662,7 @@ static int bnx2x_fill_frag_skb(struct bnx2x *bp, struct bnx2x_fastpath *fp,
 static void bnx2x_frag_free(const struct bnx2x_fastpath *fp, void *data)
 {
 	if (fp->rx_frag_size)
-		put_page(virt_to_head_page(data));
+		skb_free_frag(data);
 	else
 		kfree(data);
 }

drivers/net/ethernet/broadcom/tg3.c

@@ -6618,7 +6618,7 @@ static void tg3_tx(struct tg3_napi *tnapi)
 static void tg3_frag_free(bool is_frag, void *data)
 {
 	if (is_frag)
-		put_page(virt_to_head_page(data));
+		skb_free_frag(data);
 	else
 		kfree(data);
 }

drivers/net/ethernet/hisilicon/hip04_eth.c

@@ -798,7 +798,7 @@ static void hip04_free_ring(struct net_device *ndev, struct device *d)
 
 	for (i = 0; i < RX_DESC_NUM; i++)
 		if (priv->rx_buf[i])
-			put_page(virt_to_head_page(priv->rx_buf[i]));
+			skb_free_frag(priv->rx_buf[i]);
 
 	for (i = 0; i < TX_DESC_NUM; i++)
 		if (priv->tx_skb[i])

drivers/net/ethernet/intel/e1000/e1000_main.c

@@ -2079,11 +2079,6 @@ static void *e1000_alloc_frag(const struct e1000_adapter *a)
 	return data;
 }
 
-static void e1000_free_frag(const void *data)
-{
-	put_page(virt_to_head_page(data));
-}
-
 /**
  * e1000_clean_rx_ring - Free Rx Buffers per Queue
  * @adapter: board private structure
@@ -2107,7 +2102,7 @@ static void e1000_clean_rx_ring(struct e1000_adapter *adapter,
 						 adapter->rx_buffer_len,
 						 DMA_FROM_DEVICE);
 			if (buffer_info->rxbuf.data) {
-				e1000_free_frag(buffer_info->rxbuf.data);
+				skb_free_frag(buffer_info->rxbuf.data);
 				buffer_info->rxbuf.data = NULL;
 			}
 		} else if (adapter->clean_rx == e1000_clean_jumbo_rx_irq) {
@@ -4594,28 +4589,28 @@ static void e1000_alloc_rx_buffers(struct e1000_adapter *adapter,
 			data = e1000_alloc_frag(adapter);
 			/* Failed allocation, critical failure */
 			if (!data) {
-				e1000_free_frag(olddata);
+				skb_free_frag(olddata);
 				adapter->alloc_rx_buff_failed++;
 				break;
 			}
 
 			if (!e1000_check_64k_bound(adapter, data, bufsz)) {
 				/* give up */
-				e1000_free_frag(data);
+				skb_free_frag(data);
-				e1000_free_frag(olddata);
+				skb_free_frag(olddata);
 				adapter->alloc_rx_buff_failed++;
 				break;
 			}
 
 			/* Use new allocation */
-			e1000_free_frag(olddata);
+			skb_free_frag(olddata);
 		}
 		buffer_info->dma = dma_map_single(&pdev->dev,
 						  data,
 						  adapter->rx_buffer_len,
 						  DMA_FROM_DEVICE);
 		if (dma_mapping_error(&pdev->dev, buffer_info->dma)) {
-			e1000_free_frag(data);
+			skb_free_frag(data);
 			buffer_info->dma = 0;
 			adapter->alloc_rx_buff_failed++;
 			break;
@@ -4637,7 +4632,7 @@ static void e1000_alloc_rx_buffers(struct e1000_adapter *adapter,
 					 adapter->rx_buffer_len,
 					 DMA_FROM_DEVICE);
 
-			e1000_free_frag(data);
+			skb_free_frag(data);
 			buffer_info->rxbuf.data = NULL;
 			buffer_info->dma = 0;
 

drivers/net/ethernet/intel/igb/igb_main.c

@@ -4974,6 +4974,7 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 	struct igb_tx_buffer *first;
 	int tso;
 	u32 tx_flags = 0;
+	unsigned short f;
 	u16 count = TXD_USE_COUNT(skb_headlen(skb));
 	__be16 protocol = vlan_get_protocol(skb);
 	u8 hdr_len = 0;
@@ -4984,14 +4985,8 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 	 *       + 1 desc for context descriptor,
 	 * otherwise try next time
 	 */
-	if (NETDEV_FRAG_PAGE_MAX_SIZE > IGB_MAX_DATA_PER_TXD) {
+	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
-		unsigned short f;
+		count += TXD_USE_COUNT(skb_shinfo(skb)->frags[f].size);
-
-		for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
-			count += TXD_USE_COUNT(skb_shinfo(skb)->frags[f].size);
-	} else {
-		count += skb_shinfo(skb)->nr_frags;
-	}
 
 	if (igb_maybe_stop_tx(tx_ring, count + 3)) {
 		/* this is a hard error */

drivers/net/ethernet/marvell/mvneta.c

@@ -1359,7 +1359,7 @@ static void *mvneta_frag_alloc(const struct mvneta_port *pp)
 static void mvneta_frag_free(const struct mvneta_port *pp, void *data)
 {
 	if (likely(pp->frag_size <= PAGE_SIZE))
-		put_page(virt_to_head_page(data));
+		skb_free_frag(data);
 	else
 		kfree(data);
 }

drivers/net/ethernet/ti/netcp_core.c

@@ -537,7 +537,7 @@ int netcp_unregister_rxhook(struct netcp_intf *netcp_priv, int order,
 static void netcp_frag_free(bool is_frag, void *ptr)
 {
 	if (is_frag)
-		put_page(virt_to_head_page(ptr));
+		skb_free_frag(ptr);
 	else
 		kfree(ptr);
 }

include/linux/gfp.h

@@ -366,6 +366,11 @@ extern void free_pages(unsigned long addr, unsigned int order);
 extern void free_hot_cold_page(struct page *page, bool cold);
 extern void free_hot_cold_page_list(struct list_head *list, bool cold);
 
+struct page_frag_cache;
+extern void *__alloc_page_frag(struct page_frag_cache *nc,
+			       unsigned int fragsz, gfp_t gfp_mask);
+extern void __free_page_frag(void *addr);
+
 extern void __free_kmem_pages(struct page *page, unsigned int order);
 extern void free_kmem_pages(unsigned long addr, unsigned int order);
 

include/linux/mm_types.h

@@ -226,6 +226,24 @@ struct page_frag {
 #endif
 };
 
+#define PAGE_FRAG_CACHE_MAX_SIZE	__ALIGN_MASK(32768, ~PAGE_MASK)
+#define PAGE_FRAG_CACHE_MAX_ORDER	get_order(PAGE_FRAG_CACHE_MAX_SIZE)
+
+struct page_frag_cache {
+	void * va;
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+	__u16 offset;
+	__u16 size;
+#else
+	__u32 offset;
+#endif
+	/* we maintain a pagecount bias, so that we dont dirty cache line
+	 * containing page->_count every time we allocate a fragment.
+	 */
+	unsigned int		pagecnt_bias;
+	bool pfmemalloc;
+};
+
 typedef unsigned long __nocast vm_flags_t;
 
 /*

include/linux/skbuff.h

@@ -2128,10 +2128,6 @@ static inline void __skb_queue_purge(struct sk_buff_head *list)
 		kfree_skb(skb);
 }
 
-#define NETDEV_FRAG_PAGE_MAX_ORDER get_order(32768)
-#define NETDEV_FRAG_PAGE_MAX_SIZE  (PAGE_SIZE << NETDEV_FRAG_PAGE_MAX_ORDER)
-#define NETDEV_PAGECNT_MAX_BIAS	   NETDEV_FRAG_PAGE_MAX_SIZE
-
 void *netdev_alloc_frag(unsigned int fragsz);
 
 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
@@ -2186,6 +2182,11 @@ static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
 	return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
 }
 
+static inline void skb_free_frag(void *addr)
+{
+	__free_page_frag(addr);
+}
+
 void *napi_alloc_frag(unsigned int fragsz);
 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
 				 unsigned int length, gfp_t gfp_mask);

mm/page_alloc.c

@@ -2966,6 +2966,104 @@ void free_pages(unsigned long addr, unsigned int order)
 
 EXPORT_SYMBOL(free_pages);
 
+/*
+ * Page Fragment:
+ *  An arbitrary-length arbitrary-offset area of memory which resides
+ *  within a 0 or higher order page.  Multiple fragments within that page
+ *  are individually refcounted, in the page's reference counter.
+ *
+ * The page_frag functions below provide a simple allocation framework for
+ * page fragments.  This is used by the network stack and network device
+ * drivers to provide a backing region of memory for use as either an
+ * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
+ */
+static struct page *__page_frag_refill(struct page_frag_cache *nc,
+				       gfp_t gfp_mask)
+{
+	struct page *page = NULL;
+	gfp_t gfp = gfp_mask;
+
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+	gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
+		    __GFP_NOMEMALLOC;
+	page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
+				PAGE_FRAG_CACHE_MAX_ORDER);
+	nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
+#endif
+	if (unlikely(!page))
+		page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
+
+	nc->va = page ? page_address(page) : NULL;
+
+	return page;
+}
+
+void *__alloc_page_frag(struct page_frag_cache *nc,
+			unsigned int fragsz, gfp_t gfp_mask)
+{
+	unsigned int size = PAGE_SIZE;
+	struct page *page;
+	int offset;
+
+	if (unlikely(!nc->va)) {
+refill:
+		page = __page_frag_refill(nc, gfp_mask);
+		if (!page)
+			return NULL;
+
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+		/* if size can vary use size else just use PAGE_SIZE */
+		size = nc->size;
+#endif
+		/* Even if we own the page, we do not use atomic_set().
+		 * This would break get_page_unless_zero() users.
+		 */
+		atomic_add(size - 1, &page->_count);
+
+		/* reset page count bias and offset to start of new frag */
+		nc->pfmemalloc = page->pfmemalloc;
+		nc->pagecnt_bias = size;
+		nc->offset = size;
+	}
+
+	offset = nc->offset - fragsz;
+	if (unlikely(offset < 0)) {
+		page = virt_to_page(nc->va);
+
+		if (!atomic_sub_and_test(nc->pagecnt_bias, &page->_count))
+			goto refill;
+
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+		/* if size can vary use size else just use PAGE_SIZE */
+		size = nc->size;
+#endif
+		/* OK, page count is 0, we can safely set it */
+		atomic_set(&page->_count, size);
+
+		/* reset page count bias and offset to start of new frag */
+		nc->pagecnt_bias = size;
+		offset = size - fragsz;
+	}
+
+	nc->pagecnt_bias--;
+	nc->offset = offset;
+
+	return nc->va + offset;
+}
+EXPORT_SYMBOL(__alloc_page_frag);
+
+/*
+ * Frees a page fragment allocated out of either a compound or order 0 page.
+ */
+void __free_page_frag(void *addr)
+{
+	struct page *page = virt_to_head_page(addr);
+
+	if (unlikely(put_page_testzero(page)))
+		__free_pages_ok(page, compound_order(page));
+}
+EXPORT_SYMBOL(__free_page_frag);
+
 /*
  * alloc_kmem_pages charges newly allocated pages to the kmem resource counter
  * of the current memory cgroup.

net/core/skbuff.c

@@ -347,94 +347,18 @@ struct sk_buff *build_skb(void *data, unsigned int frag_size)
 }
 EXPORT_SYMBOL(build_skb);
 
-struct netdev_alloc_cache {
+static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
-	struct page_frag	frag;
+static DEFINE_PER_CPU(struct page_frag_cache, napi_alloc_cache);
-	/* we maintain a pagecount bias, so that we dont dirty cache line
-	 * containing page->_count every time we allocate a fragment.
-	 */
-	unsigned int		pagecnt_bias;
-};
-static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
-static DEFINE_PER_CPU(struct netdev_alloc_cache, napi_alloc_cache);
-
-static struct page *__page_frag_refill(struct netdev_alloc_cache *nc,
-				       gfp_t gfp_mask)
-{
-	const unsigned int order = NETDEV_FRAG_PAGE_MAX_ORDER;
-	struct page *page = NULL;
-	gfp_t gfp = gfp_mask;
-
-	if (order) {
-		gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
-			    __GFP_NOMEMALLOC;
-		page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
-		nc->frag.size = PAGE_SIZE << (page ? order : 0);
-	}
-
-	if (unlikely(!page))
-		page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
-
-	nc->frag.page = page;
-
-	return page;
-}
-
-static void *__alloc_page_frag(struct netdev_alloc_cache __percpu *cache,
-			       unsigned int fragsz, gfp_t gfp_mask)
-{
-	struct netdev_alloc_cache *nc = this_cpu_ptr(cache);
-	struct page *page = nc->frag.page;
-	unsigned int size;
-	int offset;
-
-	if (unlikely(!page)) {
-refill:
-		page = __page_frag_refill(nc, gfp_mask);
-		if (!page)
-			return NULL;
-
-		/* if size can vary use frag.size else just use PAGE_SIZE */
-		size = NETDEV_FRAG_PAGE_MAX_ORDER ? nc->frag.size : PAGE_SIZE;
-
-		/* Even if we own the page, we do not use atomic_set().
-		 * This would break get_page_unless_zero() users.
-		 */
-		atomic_add(size - 1, &page->_count);
-
-		/* reset page count bias and offset to start of new frag */
-		nc->pagecnt_bias = size;
-		nc->frag.offset = size;
-	}
-
-	offset = nc->frag.offset - fragsz;
-	if (unlikely(offset < 0)) {
-		if (!atomic_sub_and_test(nc->pagecnt_bias, &page->_count))
-			goto refill;
-
-		/* if size can vary use frag.size else just use PAGE_SIZE */
-		size = NETDEV_FRAG_PAGE_MAX_ORDER ? nc->frag.size : PAGE_SIZE;
-
-		/* OK, page count is 0, we can safely set it */
-		atomic_set(&page->_count, size);
-
-		/* reset page count bias and offset to start of new frag */
-		nc->pagecnt_bias = size;
-		offset = size - fragsz;
-	}
-
-	nc->pagecnt_bias--;
-	nc->frag.offset = offset;
-
-	return page_address(page) + offset;
-}
 
 static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
 {
+	struct page_frag_cache *nc;
 	unsigned long flags;
 	void *data;
 
 	local_irq_save(flags);
-	data = __alloc_page_frag(&netdev_alloc_cache, fragsz, gfp_mask);
+	nc = this_cpu_ptr(&netdev_alloc_cache);
+	data = __alloc_page_frag(nc, fragsz, gfp_mask);
 	local_irq_restore(flags);
 	return data;
 }
@@ -454,7 +378,9 @@ EXPORT_SYMBOL(netdev_alloc_frag);
 
 static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
 {
-	return __alloc_page_frag(&napi_alloc_cache, fragsz, gfp_mask);
+	struct page_frag_cache *nc = this_cpu_ptr(&napi_alloc_cache);
+
+	return __alloc_page_frag(nc, fragsz, gfp_mask);
 }
 
 void *napi_alloc_frag(unsigned int fragsz)
@@ -463,51 +389,6 @@ void *napi_alloc_frag(unsigned int fragsz)
 }
 EXPORT_SYMBOL(napi_alloc_frag);
 
-/**
- *	__alloc_rx_skb - allocate an skbuff for rx
- *	@length: length to allocate
- *	@gfp_mask: get_free_pages mask, passed to alloc_skb
- *	@flags:	If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
- *		allocations in case we have to fallback to __alloc_skb()
- *		If SKB_ALLOC_NAPI is set, page fragment will be allocated
- *		from napi_cache instead of netdev_cache.
- *
- *	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.
- */
-static struct sk_buff *__alloc_rx_skb(unsigned int length, gfp_t gfp_mask,
-				      int flags)
-{
-	struct sk_buff *skb = NULL;
-	unsigned int fragsz = SKB_DATA_ALIGN(length) +
-			      SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
-
-	if (fragsz <= PAGE_SIZE && !(gfp_mask & (__GFP_WAIT | GFP_DMA))) {
-		void *data;
-
-		if (sk_memalloc_socks())
-			gfp_mask |= __GFP_MEMALLOC;
-
-		data = (flags & SKB_ALLOC_NAPI) ?
-			__napi_alloc_frag(fragsz, gfp_mask) :
-			__netdev_alloc_frag(fragsz, gfp_mask);
-
-		if (likely(data)) {
-			skb = build_skb(data, fragsz);
-			if (unlikely(!skb))
-				put_page(virt_to_head_page(data));
-		}
-	} else {
-		skb = __alloc_skb(length, gfp_mask,
-				  SKB_ALLOC_RX, NUMA_NO_NODE);
-	}
-	return skb;
-}
-
 /**
  *	__netdev_alloc_skb - allocate an skbuff for rx on a specific device
  *	@dev: network device to receive on
@@ -521,19 +402,52 @@ static struct sk_buff *__alloc_rx_skb(unsigned int length, gfp_t gfp_mask,
  *
  *	%NULL is returned if there is no free memory.
  */
-struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
+struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
-				   unsigned int length, gfp_t gfp_mask)
+				   gfp_t gfp_mask)
 {
+	struct page_frag_cache *nc;
+	unsigned long flags;
 	struct sk_buff *skb;
+	bool pfmemalloc;
+	void *data;
 
-	length += NET_SKB_PAD;
+	len += NET_SKB_PAD;
-	skb = __alloc_rx_skb(length, gfp_mask, 0);
 
-	if (likely(skb)) {
+	if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) ||
-		skb_reserve(skb, NET_SKB_PAD);
+	    (gfp_mask & (__GFP_WAIT | GFP_DMA)))
-		skb->dev = dev;
+		return __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
+
+	len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	len = SKB_DATA_ALIGN(len);
+
+	if (sk_memalloc_socks())
+		gfp_mask |= __GFP_MEMALLOC;
+
+	local_irq_save(flags);
+
+	nc = this_cpu_ptr(&netdev_alloc_cache);
+	data = __alloc_page_frag(nc, len, gfp_mask);
+	pfmemalloc = nc->pfmemalloc;
+
+	local_irq_restore(flags);
+
+	if (unlikely(!data))
+		return NULL;
+
+	skb = __build_skb(data, len);
+	if (unlikely(!skb)) {
+		skb_free_frag(data);
+		return NULL;
 	}
 
+	/* use OR instead of assignment to avoid clearing of bits in mask */
+	if (pfmemalloc)
+		skb->pfmemalloc = 1;
+	skb->head_frag = 1;
+
+	skb_reserve(skb, NET_SKB_PAD);
+	skb->dev = dev;
+
 	return skb;
 }
 EXPORT_SYMBOL(__netdev_alloc_skb);
@@ -551,19 +465,43 @@ EXPORT_SYMBOL(__netdev_alloc_skb);
  *
  *	%NULL is returned if there is no free memory.
  */
-struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
+struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
-				 unsigned int length, gfp_t gfp_mask)
+				 gfp_t gfp_mask)
 {
+	struct page_frag_cache *nc = this_cpu_ptr(&napi_alloc_cache);
 	struct sk_buff *skb;
+	void *data;
 
-	length += NET_SKB_PAD + NET_IP_ALIGN;
+	len += NET_SKB_PAD + NET_IP_ALIGN;
-	skb = __alloc_rx_skb(length, gfp_mask, SKB_ALLOC_NAPI);
 
-	if (likely(skb)) {
+	if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) ||
-		skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
+	    (gfp_mask & (__GFP_WAIT | GFP_DMA)))
-		skb->dev = napi->dev;
+		return __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
+
+	len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	len = SKB_DATA_ALIGN(len);
+
+	if (sk_memalloc_socks())
+		gfp_mask |= __GFP_MEMALLOC;
+
+	data = __alloc_page_frag(nc, len, gfp_mask);
+	if (unlikely(!data))
+		return NULL;
+
+	skb = __build_skb(data, len);
+	if (unlikely(!skb)) {
+		skb_free_frag(data);
+		return NULL;
 	}
 
+	/* use OR instead of assignment to avoid clearing of bits in mask */
+	if (nc->pfmemalloc)
+		skb->pfmemalloc = 1;
+	skb->head_frag = 1;
+
+	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
+	skb->dev = napi->dev;
+
 	return skb;
 }
 EXPORT_SYMBOL(__napi_alloc_skb);
@@ -611,10 +549,12 @@ static void skb_clone_fraglist(struct sk_buff *skb)
 
 static void skb_free_head(struct sk_buff *skb)
 {
+	unsigned char *head = skb->head;
+
 	if (skb->head_frag)
-		put_page(virt_to_head_page(skb->head));
+		skb_free_frag(head);
 	else
-		kfree(skb->head);
+		kfree(head);
 }
 
 static void skb_release_data(struct sk_buff *skb)