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Commit 39e50d96 authored by Zhu Yanjun's avatar Zhu Yanjun Committed by David S. Miller
Browse files

forcedeth: optimize the xmit/rx with unlikely 



In the xmit/rx fastpath, the function dma_map_single rarely fails.
Therefore, add an unlikely() optimization to this error check
conditional.

Signed-off-by: default avatarZhu Yanjun <yanjun.zhu@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1f8d31d1

drivers/net/ethernet/nvidia/forcedeth.c

+14 −12
Original line number Diff line number Diff line
@@ -1817,8 +1817,8 @@ static int nv_alloc_rx(struct net_device *dev) 
							     skb->data,

							     skb_tailroom(skb),

							     DMA_FROM_DEVICE);

			if (dma_mapping_error(&np->pci_dev->dev,

					      np->put_rx_ctx->dma)) {

			if (unlikely(dma_mapping_error(&np->pci_dev->dev,

						       np->put_rx_ctx->dma))) {

				kfree_skb(skb);

				goto packet_dropped;

			}
@@ -1858,8 +1858,8 @@ static int nv_alloc_rx_optimized(struct net_device *dev) 
							     skb->data,

							     skb_tailroom(skb),

							     DMA_FROM_DEVICE);

			if (dma_mapping_error(&np->pci_dev->dev,

					      np->put_rx_ctx->dma)) {

			if (unlikely(dma_mapping_error(&np->pci_dev->dev,

						       np->put_rx_ctx->dma))) {

				kfree_skb(skb);

				goto packet_dropped;

			}
@@ -2227,8 +2227,8 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		np->put_tx_ctx->dma = dma_map_single(&np->pci_dev->dev,

						     skb->data + offset, bcnt,

						     DMA_TO_DEVICE);

		if (dma_mapping_error(&np->pci_dev->dev,

				      np->put_tx_ctx->dma)) {

		if (unlikely(dma_mapping_error(&np->pci_dev->dev,

					       np->put_tx_ctx->dma))) {

			/* on DMA mapping error - drop the packet */

			dev_kfree_skb_any(skb);

			u64_stats_update_begin(&np->swstats_tx_syncp);
@@ -2268,7 +2268,8 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev) 
							frag, offset,

							bcnt,

							DMA_TO_DEVICE);

			if (dma_mapping_error(&np->pci_dev->dev, np->put_tx_ctx->dma)) {

			if (unlikely(dma_mapping_error(&np->pci_dev->dev,

						       np->put_tx_ctx->dma))) {



				/* Unwind the mapped fragments */

				do {
@@ -2377,8 +2378,8 @@ static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb, 
		np->put_tx_ctx->dma = dma_map_single(&np->pci_dev->dev,

						     skb->data + offset, bcnt,

						     DMA_TO_DEVICE);

		if (dma_mapping_error(&np->pci_dev->dev,

				      np->put_tx_ctx->dma)) {

		if (unlikely(dma_mapping_error(&np->pci_dev->dev,

					       np->put_tx_ctx->dma))) {

			/* on DMA mapping error - drop the packet */

			dev_kfree_skb_any(skb);

			u64_stats_update_begin(&np->swstats_tx_syncp);
@@ -2419,7 +2420,8 @@ static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb, 
							bcnt,

							DMA_TO_DEVICE);



			if (dma_mapping_error(&np->pci_dev->dev, np->put_tx_ctx->dma)) {

			if (unlikely(dma_mapping_error(&np->pci_dev->dev,

						       np->put_tx_ctx->dma))) {



				/* Unwind the mapped fragments */

				do {
@@ -5075,8 +5077,8 @@ static int nv_loopback_test(struct net_device *dev) 
	test_dma_addr = dma_map_single(&np->pci_dev->dev, tx_skb->data,

				       skb_tailroom(tx_skb),

				       DMA_FROM_DEVICE);

	if (dma_mapping_error(&np->pci_dev->dev,

			      test_dma_addr)) {

	if (unlikely(dma_mapping_error(&np->pci_dev->dev,

				       test_dma_addr))) {

		dev_kfree_skb_any(tx_skb);

		goto out;

	}