igb: split buffer_info into tx_buffer_info and rx_buffer_info

In order to be able to improve the performance of the TX path it has been
necessary to add addition info to the tx_buffer_info structure.  However a
side effect is that the structure has gotten larger and this in turn has
also increased the size of the RX buffer info structure.  In order to avoid
this in the future I am splitting the single buffer_info structure into two
separate ones and instead I will join them by making the buffer_info
pointer in the ring a union of the two.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown  <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb.h

@@ -132,27 +132,24 @@ struct vf_data_storage {
 
 /* wrapper around a pointer to a socket buffer,
  * so a DMA handle can be stored along with the buffer */
-struct igb_buffer {
-	struct sk_buff *skb;
-	dma_addr_t dma;
-	union {
-		/* TX */
-		struct {
-			unsigned long time_stamp;
-			u16 length;
+struct igb_tx_buffer {
 	u16 next_to_watch;
+	unsigned long time_stamp;
+	dma_addr_t dma;
+	u32 length;
+	u32 tx_flags;
+	struct sk_buff *skb;
 	unsigned int bytecount;
 	u16 gso_segs;
-			u8 tx_flags;
 	u8 mapped_as_page;
-		};
-		/* RX */
-		struct {
+};
+
+struct igb_rx_buffer {
+	struct sk_buff *skb;
+	dma_addr_t dma;
 	struct page *page;
 	dma_addr_t page_dma;
-			u16 page_offset;
-		};
-	};
+	u32 page_offset;
 };
 
 struct igb_tx_queue_stats {
@@ -191,7 +188,10 @@ struct igb_ring {
 	struct igb_q_vector *q_vector;	/* backlink to q_vector */
 	struct net_device *netdev;	/* back pointer to net_device */
 	struct device *dev;		/* device pointer for dma mapping */
-	struct igb_buffer *buffer_info;	/* array of buffer info structs */
+	union {				/* array of buffer info structs */
+		struct igb_tx_buffer *tx_buffer_info;
+		struct igb_rx_buffer *rx_buffer_info;
+	};
 	void *desc;			/* descriptor ring memory */
 	unsigned long flags;		/* ring specific flags */
 	void __iomem *tail;		/* pointer to ring tail register */
@@ -377,7 +377,7 @@ extern void igb_setup_tctl(struct igb_adapter *);
 extern void igb_setup_rctl(struct igb_adapter *);
 extern netdev_tx_t igb_xmit_frame_ring(struct sk_buff *, struct igb_ring *);
 extern void igb_unmap_and_free_tx_resource(struct igb_ring *,
-					   struct igb_buffer *);
+					   struct igb_tx_buffer *);
 extern void igb_alloc_rx_buffers(struct igb_ring *, u16);
 extern void igb_update_stats(struct igb_adapter *, struct rtnl_link_stats64 *);
 extern bool igb_has_link(struct igb_adapter *adapter);

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

@@ -1579,7 +1579,8 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
                                 unsigned int size)
 {
 	union e1000_adv_rx_desc *rx_desc;
-	struct igb_buffer *buffer_info;
+	struct igb_rx_buffer *rx_buffer_info;
+	struct igb_tx_buffer *tx_buffer_info;
 	int rx_ntc, tx_ntc, count = 0;
 	u32 staterr;
 
@@ -1591,22 +1592,22 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
 
 	while (staterr & E1000_RXD_STAT_DD) {
 		/* check rx buffer */
-		buffer_info = &rx_ring->buffer_info[rx_ntc];
+		rx_buffer_info = &rx_ring->rx_buffer_info[rx_ntc];
 
 		/* unmap rx buffer, will be remapped by alloc_rx_buffers */
 		dma_unmap_single(rx_ring->dev,
-		                 buffer_info->dma,
+				 rx_buffer_info->dma,
 				 IGB_RX_HDR_LEN,
 				 DMA_FROM_DEVICE);
-		buffer_info->dma = 0;
+		rx_buffer_info->dma = 0;
 
 		/* verify contents of skb */
-		if (!igb_check_lbtest_frame(buffer_info->skb, size))
+		if (!igb_check_lbtest_frame(rx_buffer_info->skb, size))
 			count++;
 
 		/* unmap buffer on tx side */
-		buffer_info = &tx_ring->buffer_info[tx_ntc];
-		igb_unmap_and_free_tx_resource(tx_ring, buffer_info);
+		tx_buffer_info = &tx_ring->tx_buffer_info[tx_ntc];
+		igb_unmap_and_free_tx_resource(tx_ring, tx_buffer_info);
 
 		/* increment rx/tx next to clean counters */
 		rx_ntc++;