1 files changed, 117 insertions, 98 deletions

diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index d4e488267988..b758846d4dc5 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -501,14 +501,15 @@ void i40evf_clean_rx_ring(struct i40e_ring *rx_ring)
 	if (!rx_ring->rx_bi)
 		return;
 
+	if (rx_ring->skb) {
+		dev_kfree_skb(rx_ring->skb);
+		rx_ring->skb = NULL;
+	}
+
 	/* Free all the Rx ring sk_buffs */
 	for (i = 0; i < rx_ring->count; i++) {
 		struct i40e_rx_buffer *rx_bi = &rx_ring->rx_bi[i];
 
-		if (rx_bi->skb) {
-			dev_kfree_skb(rx_bi->skb);
-			rx_bi->skb = NULL;
-		}
 		if (!rx_bi->page)
 			continue;
 
@@ -903,45 +904,6 @@ void i40evf_process_skb_fields(struct i40e_ring *rx_ring,
 }
 
 /**
- * i40e_pull_tail - i40e specific version of skb_pull_tail
- * @rx_ring: rx descriptor ring packet is being transacted on
- * @skb: pointer to current skb being adjusted
- *
- * This function is an i40e specific version of __pskb_pull_tail.  The
- * main difference between this version and the original function is that
- * this function can make several assumptions about the state of things
- * that allow for significant optimizations versus the standard function.
- * As a result we can do things like drop a frag and maintain an accurate
- * truesize for the skb.
- */
-static void i40e_pull_tail(struct i40e_ring *rx_ring, struct sk_buff *skb)
-{
-	struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
-	unsigned char *va;
-	unsigned int pull_len;
-
-	/* it is valid to use page_address instead of kmap since we are
-	 * working with pages allocated out of the lomem pool per
-	 * alloc_page(GFP_ATOMIC)
-	 */
-	va = skb_frag_address(frag);
-
-	/* we need the header to contain the greater of either ETH_HLEN or
-	 * 60 bytes if the skb->len is less than 60 for skb_pad.
-	 */
-	pull_len = eth_get_headlen(va, I40E_RX_HDR_SIZE);
-
-	/* align pull length to size of long to optimize memcpy performance */
-	skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long)));
-
-	/* update all of the pointers */
-	skb_frag_size_sub(frag, pull_len);
-	frag->page_offset += pull_len;
-	skb->data_len -= pull_len;
-	skb->tail += pull_len;
-}
-
-/**
  * i40e_cleanup_headers - Correct empty headers
  * @rx_ring: rx descriptor ring packet is being transacted on
  * @skb: pointer to current skb being fixed
@@ -956,10 +918,6 @@ static void i40e_pull_tail(struct i40e_ring *rx_ring, struct sk_buff *skb)
  **/
 static bool i40e_cleanup_headers(struct i40e_ring *rx_ring, struct sk_buff *skb)
 {
-	/* place header in linear portion of buffer */
-	if (skb_is_nonlinear(skb))
-		i40e_pull_tail(rx_ring, skb);
-
 	/* if eth_skb_pad returns an error the skb was freed */
 	if (eth_skb_pad(skb))
 		return true;
@@ -991,19 +949,85 @@ static void i40e_reuse_rx_page(struct i40e_ring *rx_ring,
 }
 
 /**
- * i40e_page_is_reserved - check if reuse is possible
+ * i40e_page_is_reusable - check if any reuse is possible
  * @page: page struct to check
+ *
+ * A page is not reusable if it was allocated under low memory
+ * conditions, or it's not in the same NUMA node as this CPU.
  */
-static inline bool i40e_page_is_reserved(struct page *page)
+static inline bool i40e_page_is_reusable(struct page *page)
 {
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
+	return (page_to_nid(page) == numa_mem_id()) &&
+		!page_is_pfmemalloc(page);
+}
+
+/**
+ * i40e_can_reuse_rx_page - Determine if this page can be reused by
+ * the adapter for another receive
+ *
+ * @rx_buffer: buffer containing the page
+ * @page: page address from rx_buffer
+ * @truesize: actual size of the buffer in this page
+ *
+ * If page is reusable, rx_buffer->page_offset is adjusted to point to
+ * an unused region in the page.
+ *
+ * For small pages, @truesize will be a constant value, half the size
+ * of the memory at page.  We'll attempt to alternate between high and
+ * low halves of the page, with one half ready for use by the hardware
+ * and the other half being consumed by the stack.  We use the page
+ * ref count to determine whether the stack has finished consuming the
+ * portion of this page that was passed up with a previous packet.  If
+ * the page ref count is >1, we'll assume the "other" half page is
+ * still busy, and this page cannot be reused.
+ *
+ * For larger pages, @truesize will be the actual space used by the
+ * received packet (adjusted upward to an even multiple of the cache
+ * line size).  This will advance through the page by the amount
+ * actually consumed by the received packets while there is still
+ * space for a buffer.  Each region of larger pages will be used at
+ * most once, after which the page will not be reused.
+ *
+ * In either case, if the page is reusable its refcount is increased.
+ **/
+static bool i40e_can_reuse_rx_page(struct i40e_rx_buffer *rx_buffer,
+				   struct page *page,
+				   const unsigned int truesize)
+{
+#if (PAGE_SIZE >= 8192)
+	unsigned int last_offset = PAGE_SIZE - I40E_RXBUFFER_2048;
+#endif
+
+	/* Is any reuse possible? */
+	if (unlikely(!i40e_page_is_reusable(page)))
+		return false;
+
+#if (PAGE_SIZE < 8192)
+	/* if we are only owner of page we can reuse it */
+	if (unlikely(page_count(page) != 1))
+		return false;
+
+	/* flip page offset to other buffer */
+	rx_buffer->page_offset ^= truesize;
+#else
+	/* move offset up to the next cache line */
+	rx_buffer->page_offset += truesize;
+
+	if (rx_buffer->page_offset > last_offset)
+		return false;
+#endif
+
+	/* Inc ref count on page before passing it up to the stack */
+	get_page(page);
+
+	return true;
 }
 
 /**
  * i40e_add_rx_frag - Add contents of Rx buffer to sk_buff
  * @rx_ring: rx descriptor ring to transact packets on
  * @rx_buffer: buffer containing page to add
- * @rx_desc: descriptor containing length of buffer written by hardware
+ * @size: packet length from rx_desc
  * @skb: sk_buff to place the data into
  *
  * This function will add the data contained in rx_buffer->page to the skb.
@@ -1016,30 +1040,29 @@ static inline bool i40e_page_is_reserved(struct page *page)
  **/
 static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
 			     struct i40e_rx_buffer *rx_buffer,
-			     union i40e_rx_desc *rx_desc,
+			     unsigned int size,
 			     struct sk_buff *skb)
 {
 	struct page *page = rx_buffer->page;
-	u64 qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
-	unsigned int size = (qword & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
-			    I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
+	unsigned char *va = page_address(page) + rx_buffer->page_offset;
 #if (PAGE_SIZE < 8192)
 	unsigned int truesize = I40E_RXBUFFER_2048;
 #else
 	unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
-	unsigned int last_offset = PAGE_SIZE - I40E_RXBUFFER_2048;
 #endif
+	unsigned int pull_len;
+
+	if (unlikely(skb_is_nonlinear(skb)))
+		goto add_tail_frag;
 
 	/* will the data fit in the skb we allocated? if so, just
 	 * copy it as it is pretty small anyway
 	 */
-	if ((size <= I40E_RX_HDR_SIZE) && !skb_is_nonlinear(skb)) {
-		unsigned char *va = page_address(page) + rx_buffer->page_offset;
-
+	if (size <= I40E_RX_HDR_SIZE) {
 		memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
 
-		/* page is not reserved, we can reuse buffer as-is */
-		if (likely(!i40e_page_is_reserved(page)))
+		/* page is reusable, we can reuse buffer as-is */
+		if (likely(i40e_page_is_reusable(page)))
 			return true;
 
 		/* this page cannot be reused so discard it */
@@ -1047,34 +1070,26 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
 		return false;
 	}
 
-	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
-			rx_buffer->page_offset, size, truesize);
-
-	/* avoid re-using remote pages */
-	if (unlikely(i40e_page_is_reserved(page)))
-		return false;
-
-#if (PAGE_SIZE < 8192)
-	/* if we are only owner of page we can reuse it */
-	if (unlikely(page_count(page) != 1))
-		return false;
+	/* we need the header to contain the greater of either
+	 * ETH_HLEN or 60 bytes if the skb->len is less than
+	 * 60 for skb_pad.
+	 */
+	pull_len = eth_get_headlen(va, I40E_RX_HDR_SIZE);
 
-	/* flip page offset to other buffer */
-	rx_buffer->page_offset ^= truesize;
-#else
-	/* move offset up to the next cache line */
-	rx_buffer->page_offset += truesize;
+	/* align pull length to size of long to optimize
+	 * memcpy performance
+	 */
+	memcpy(__skb_put(skb, pull_len), va, ALIGN(pull_len, sizeof(long)));
 
-	if (rx_buffer->page_offset > last_offset)
-		return false;
-#endif
+	/* update all of the pointers */
+	va += pull_len;
+	size -= pull_len;
 
-	/* Even if we own the page, we are not allowed to use atomic_set()
-	 * This would break get_page_unless_zero() users.
-	 */
-	get_page(rx_buffer->page);
+add_tail_frag:
+	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
+			(unsigned long)va & ~PAGE_MASK, size, truesize);
 
-	return true;
+	return i40e_can_reuse_rx_page(rx_buffer, page, truesize);
 }
 
 /**
@@ -1089,18 +1104,21 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
  */
 static inline
 struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,
-				       union i40e_rx_desc *rx_desc)
+				       union i40e_rx_desc *rx_desc,
+				       struct sk_buff *skb)
 {
+	u64 local_status_error_len =
+		le64_to_cpu(rx_desc->wb.qword1.status_error_len);
+	unsigned int size =
+		(local_status_error_len & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
+		I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
 	struct i40e_rx_buffer *rx_buffer;
-	struct sk_buff *skb;
 	struct page *page;
 
 	rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];
 	page = rx_buffer->page;
 	prefetchw(page);
 
-	skb = rx_buffer->skb;
-
 	if (likely(!skb)) {
 		void *page_addr = page_address(page) + rx_buffer->page_offset;
 
@@ -1124,19 +1142,17 @@ struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,
 		 * it now to avoid a possible cache miss
 		 */
 		prefetchw(skb->data);
-	} else {
-		rx_buffer->skb = NULL;
 	}
 
 	/* we are reusing so sync this buffer for CPU use */
 	dma_sync_single_range_for_cpu(rx_ring->dev,
 				      rx_buffer->dma,
 				      rx_buffer->page_offset,
-				      I40E_RXBUFFER_2048,
+				      size,
 				      DMA_FROM_DEVICE);
 
 	/* pull page into skb */
-	if (i40e_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
+	if (i40e_add_rx_frag(rx_ring, rx_buffer, size, skb)) {
 		/* hand second half of page back to the ring */
 		i40e_reuse_rx_page(rx_ring, rx_buffer);
 		rx_ring->rx_stats.page_reuse_count++;
@@ -1180,8 +1196,6 @@ static bool i40e_is_non_eop(struct i40e_ring *rx_ring,
 	if (likely(i40e_test_staterr(rx_desc, I40E_RXD_EOF)))
 		return false;
 
-	/* place skb in next buffer to be received */
-	rx_ring->rx_bi[ntc].skb = skb;
 	rx_ring->rx_stats.non_eop_descs++;
 
 	return true;
@@ -1202,12 +1216,12 @@ static bool i40e_is_non_eop(struct i40e_ring *rx_ring,
 static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 {
 	unsigned int total_rx_bytes = 0, total_rx_packets = 0;
+	struct sk_buff *skb = rx_ring->skb;
 	u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
 	bool failure = false;
 
 	while (likely(total_rx_packets < budget)) {
 		union i40e_rx_desc *rx_desc;
-		struct sk_buff *skb;
 		u16 vlan_tag;
 		u8 rx_ptype;
 		u64 qword;
@@ -1236,7 +1250,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 		 */
 		dma_rmb();
 
-		skb = i40evf_fetch_rx_buffer(rx_ring, rx_desc);
+		skb = i40evf_fetch_rx_buffer(rx_ring, rx_desc, skb);
 		if (!skb)
 			break;
 
@@ -1255,8 +1269,10 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 			continue;
 		}
 
-		if (i40e_cleanup_headers(rx_ring, skb))
+		if (i40e_cleanup_headers(rx_ring, skb)) {
+			skb = NULL;
 			continue;
+		}
 
 		/* probably a little skewed due to removing CRC */
 		total_rx_bytes += skb->len;
@@ -1273,11 +1289,14 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 			   le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1) : 0;
 
 		i40e_receive_skb(rx_ring, skb, vlan_tag);
+		skb = NULL;
 
 		/* update budget accounting */
 		total_rx_packets++;
 	}
 
+	rx_ring->skb = skb;
+
 	u64_stats_update_begin(&rx_ring->syncp);
 	rx_ring->stats.packets += total_rx_packets;
 	rx_ring->stats.bytes += total_rx_bytes;