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Date: Fri, 22 Sep 2017 10:20:21 -0400
From: Zhu Yanjun <yanjun.zhu@...cle.com>
To: davem@...emloft.net, jarod@...hat.com, netdev@...r.kernel.org
Subject: [PATCH 1/1] 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: Zhu Yanjun <yanjun.zhu@...cle.com>
---
drivers/net/ethernet/nvidia/forcedeth.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
index 0a7ba3a..63a9e1e 100644
--- a/drivers/net/ethernet/nvidia/forcedeth.c
+++ b/drivers/net/ethernet/nvidia/forcedeth.c
@@ -1816,8 +1816,8 @@ 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;
}
@@ -1857,8 +1857,8 @@ 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;
}
@@ -2224,8 +2224,8 @@ 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);
@@ -2265,7 +2265,8 @@ 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 {
@@ -2373,8 +2374,8 @@ 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);
@@ -2415,7 +2416,8 @@ 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 {
@@ -5070,8 +5072,8 @@ 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;
}
--
2.7.4
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