[Patch net-next 05/12] net: hns3: add unlikely for error handling in data path

From: Huazhong Tan
Date: Sat Feb 23 2019 - 04:23:38 EST


From: Yunsheng Lin <linyunsheng@xxxxxxxxxx>

This patch adds unlikely hint for error handling in critical data
path.

Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
Signed-off-by: Huazhong Tan <tanhuazhong@xxxxxxxxxx>
---
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 33ac732..50bfdba 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -619,7 +619,7 @@ static int hns3_set_tso(struct sk_buff *skb, u32 *paylen,
return 0;

ret = skb_cow_head(skb, 0);
- if (ret)
+ if (unlikely(ret))
return ret;

l3.hdr = skb_network_header(skb);
@@ -1012,7 +1012,7 @@ static int hns3_fill_desc_vtags(struct sk_buff *skb,
int rc;

rc = skb_cow_head(skb, 0);
- if (rc < 0)
+ if (unlikely(rc < 0))
return rc;
vhdr = (struct vlan_ethhdr *)skb->data;
vhdr->h_vlan_TCI |= cpu_to_be16((skb->priority & 0x7)
@@ -1057,7 +1057,7 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
skb_reset_mac_len(skb);

ret = hns3_get_l4_protocol(skb, &ol4_proto, &il4_proto);
- if (ret)
+ if (unlikely(ret))
return ret;
hns3_set_l2l3l4_len(skb, ol4_proto, il4_proto,
&type_cs_vlan_tso,
@@ -1065,12 +1065,12 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
ret = hns3_set_l3l4_type_csum(skb, ol4_proto, il4_proto,
&type_cs_vlan_tso,
&ol_type_vlan_len_msec);
- if (ret)
+ if (unlikely(ret))
return ret;

ret = hns3_set_tso(skb, &paylen, &mss,
&type_cs_vlan_tso);
- if (ret)
+ if (unlikely(ret))
return ret;
}

@@ -1090,7 +1090,7 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
dma = skb_frag_dma_map(dev, frag, 0, size, DMA_TO_DEVICE);
}

- if (dma_mapping_error(ring->dev, dma)) {
+ if (unlikely(dma_mapping_error(ring->dev, dma))) {
ring->stats.sw_err_cnt++;
return -ENOMEM;
}
@@ -1150,7 +1150,7 @@ static int hns3_nic_maybe_stop_tso(struct sk_buff **out_skb, int *bnum,
size = skb_frag_size(frag);
bdnum_for_frag = (size + HNS3_MAX_BD_SIZE - 1) >>
HNS3_MAX_BD_SIZE_OFFSET;
- if (bdnum_for_frag > HNS3_MAX_BD_PER_FRAG)
+ if (unlikely(bdnum_for_frag > HNS3_MAX_BD_PER_FRAG))
return -ENOMEM;

buf_num += bdnum_for_frag;
@@ -1281,7 +1281,7 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev)

ret = hns3_fill_desc(ring, skb, size, seg_num == 1 ? 1 : 0,
DESC_TYPE_SKB);
- if (ret)
+ if (unlikely(ret))
goto head_fill_err;

next_to_use_frag = ring->next_to_use;
@@ -1294,7 +1294,7 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev)
seg_num - 1 == i ? 1 : 0,
DESC_TYPE_PAGE);

- if (ret)
+ if (unlikely(ret))
goto frag_fill_err;
}

--
2.7.4