ixgbevf: redo dma mapping using the tx buffer info

This patch takes advantage of the dma buffer always being present in the
first descriptor and mapped as single. As such we can call dma_unmap_single
and don't need to check for DMA mapping in ixgbevf_clean_tx_irq().

In addition this patch makes use of the DMA API.
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbevf/ixgbevf.h

@@ -52,9 +52,9 @@ struct ixgbevf_tx_buffer {
 	unsigned int bytecount;
 	unsigned short gso_segs;
 	__be16 protocol;
-	dma_addr_t dma;
+	DEFINE_DMA_UNMAP_ADDR(dma);
+	DEFINE_DMA_UNMAP_LEN(len);
 	u32 tx_flags;
-	u16 length;
 };
 
 struct ixgbevf_rx_buffer {
@@ -147,7 +147,6 @@ struct ixgbevf_ring {
 #define IXGBE_TX_FLAGS_VLAN		(u32)(1 << 1)
 #define IXGBE_TX_FLAGS_TSO		(u32)(1 << 2)
 #define IXGBE_TX_FLAGS_IPV4		(u32)(1 << 3)
-#define IXGBE_TX_FLAGS_MAPPED_AS_PAGE	(u32)(1 << 4)
 #define IXGBE_TX_FLAGS_VLAN_MASK	0xffff0000
 #define IXGBE_TX_FLAGS_VLAN_PRIO_MASK	0x0000e000
 #define IXGBE_TX_FLAGS_VLAN_SHIFT	16

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -145,28 +145,25 @@ static void ixgbevf_set_ivar(struct ixgbevf_adapter *adapter, s8 direction,
 }
 
 static void ixgbevf_unmap_and_free_tx_resource(struct ixgbevf_ring *tx_ring,
-					       struct ixgbevf_tx_buffer
-					       *tx_buffer_info)
-{
-	if (tx_buffer_info->dma) {
-		if (tx_buffer_info->tx_flags & IXGBE_TX_FLAGS_MAPPED_AS_PAGE)
-			dma_unmap_page(tx_ring->dev,
-				       tx_buffer_info->dma,
-				       tx_buffer_info->length,
-				       DMA_TO_DEVICE);
-		else
+					struct ixgbevf_tx_buffer *tx_buffer)
+{
+	if (tx_buffer->skb) {
+		dev_kfree_skb_any(tx_buffer->skb);
+		if (dma_unmap_len(tx_buffer, len))
 			dma_unmap_single(tx_ring->dev,
-					 tx_buffer_info->dma,
-					 tx_buffer_info->length,
+					 dma_unmap_addr(tx_buffer, dma),
+					 dma_unmap_len(tx_buffer, len),
 					 DMA_TO_DEVICE);
-		tx_buffer_info->dma = 0;
-	}
-	if (tx_buffer_info->skb) {
-		dev_kfree_skb_any(tx_buffer_info->skb);
-		tx_buffer_info->skb = NULL;
+	} else if (dma_unmap_len(tx_buffer, len)) {
+		dma_unmap_page(tx_ring->dev,
+			       dma_unmap_addr(tx_buffer, dma),
+			       dma_unmap_len(tx_buffer, len),
+			       DMA_TO_DEVICE);
 	}
-	tx_buffer_info->time_stamp = 0;
-	/* tx_buffer_info must be completely set up in the transmit path */
+	tx_buffer->next_to_watch = NULL;
+	tx_buffer->skb = NULL;
+	dma_unmap_len_set(tx_buffer, len, 0);
+	/* tx_buffer must be completely set up in the transmit path */
 }
 
 #define IXGBE_MAX_TXD_PWR	14
@@ -221,8 +218,18 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_q_vector *q_vector,
 		total_bytes += tx_buffer->bytecount;
 		total_packets += tx_buffer->gso_segs;
 
+		/* free the skb */
+		dev_kfree_skb_any(tx_buffer->skb);
+
+		/* unmap skb header data */
+		dma_unmap_single(tx_ring->dev,
+				 dma_unmap_addr(tx_buffer, dma),
+				 dma_unmap_len(tx_buffer, len),
+				 DMA_TO_DEVICE);
+
 		/* clear tx_buffer data */
-		ixgbevf_unmap_and_free_tx_resource(tx_ring, tx_buffer);
+		tx_buffer->skb = NULL;
+		dma_unmap_len_set(tx_buffer, len, 0);
 
 		/* unmap remaining buffers */
 		while (tx_desc != eop_desc) {
@@ -237,7 +244,14 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_q_vector *q_vector,
 				tx_desc = IXGBEVF_TX_DESC(tx_ring, 0);
 			}
 
-			ixgbevf_unmap_and_free_tx_resource(tx_ring, tx_buffer);
+			/* unmap any remaining paged data */
+			if (dma_unmap_len(tx_buffer, len)) {
+				dma_unmap_page(tx_ring->dev,
+					       dma_unmap_addr(tx_buffer, dma),
+					       dma_unmap_len(tx_buffer, len),
+					       DMA_TO_DEVICE);
+				dma_unmap_len_set(tx_buffer, len, 0);
+			}
 		}
 
 		tx_desc->wb.status = 0;
@@ -2904,6 +2918,7 @@ static void ixgbevf_tx_csum(struct ixgbevf_ring *tx_ring,
 static int ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 			  struct ixgbevf_tx_buffer *first)
 {
+	dma_addr_t dma;
 	struct sk_buff *skb = first->skb;
 	struct ixgbevf_tx_buffer *tx_buffer_info;
 	unsigned int len;
@@ -2921,14 +2936,16 @@ static int ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 		tx_buffer_info = &tx_ring->tx_buffer_info[i];
 		size = min(len, (unsigned int)IXGBE_MAX_DATA_PER_TXD);
 
-		tx_buffer_info->length = size;
 		tx_buffer_info->tx_flags = first->tx_flags;
-		tx_buffer_info->dma = dma_map_single(tx_ring->dev,
-						     skb->data + offset,
-						     size, DMA_TO_DEVICE);
-		if (dma_mapping_error(tx_ring->dev, tx_buffer_info->dma))
+		dma = dma_map_single(tx_ring->dev, skb->data + offset,
+				     size, DMA_TO_DEVICE);
+		if (dma_mapping_error(tx_ring->dev, dma))
 			goto dma_error;
 
+		/* record length, and DMA address */
+		dma_unmap_len_set(tx_buffer_info, len, size);
+		dma_unmap_addr_set(tx_buffer_info, dma, dma);
+
 		len -= size;
 		total -= size;
 		offset += size;
@@ -2949,16 +2966,15 @@ static int ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 			tx_buffer_info = &tx_ring->tx_buffer_info[i];
 			size = min(len, (unsigned int)IXGBE_MAX_DATA_PER_TXD);
 
-			tx_buffer_info->length = size;
-			tx_buffer_info->dma =
-				skb_frag_dma_map(tx_ring->dev, frag,
-						 offset, size, DMA_TO_DEVICE);
-			tx_buffer_info->tx_flags |=
-						IXGBE_TX_FLAGS_MAPPED_AS_PAGE;
-			if (dma_mapping_error(tx_ring->dev,
-					      tx_buffer_info->dma))
+			dma = skb_frag_dma_map(tx_ring->dev, frag,
+					       offset, size, DMA_TO_DEVICE);
+			if (dma_mapping_error(tx_ring->dev, dma))
 				goto dma_error;
 
+			/* record length, and DMA address */
+			dma_unmap_len_set(tx_buffer_info, len, size);
+			dma_unmap_addr_set(tx_buffer_info, dma, dma);
+
 			len -= size;
 			total -= size;
 			offset += size;
@@ -3043,11 +3059,15 @@ static void ixgbevf_tx_queue(struct ixgbevf_ring *tx_ring,
 
 	i = tx_ring->next_to_use;
 	while (count--) {
+		dma_addr_t dma;
+		unsigned int len;
+
 		tx_buffer_info = &tx_ring->tx_buffer_info[i];
+		dma = dma_unmap_addr(tx_buffer_info, dma);
+		len = dma_unmap_len(tx_buffer_info, len);
 		tx_desc = IXGBEVF_TX_DESC(tx_ring, i);
-		tx_desc->read.buffer_addr = cpu_to_le64(tx_buffer_info->dma);
-		tx_desc->read.cmd_type_len =
-			cpu_to_le32(cmd_type_len | tx_buffer_info->length);
+		tx_desc->read.buffer_addr = cpu_to_le64(dma);
+		tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type_len | len);
 		tx_desc->read.olinfo_status = cpu_to_le32(olinfo_status);
 		i++;
 		if (i == tx_ring->count)