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mlx4: do not access rx_desc from mlx4_en_process_rx_cq()

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Instead of fetching dma address from rx_desc->data[0].addr,
prefer using frags[0].dma + frags[0].page_offset to avoid
a potential cache line miss.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2017-03-08 08:17:15 -08:00 committed by David S. Miller
parent 7d7bfc6a3f
commit 9e8c0395a7
1 changed files with 3 additions and 6 deletions
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9
drivers/net/ethernet/mellanox/mlx4/en_rx.c
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@ -528,7 +528,6 @@ fail:
static struct sk_buff *mlx4_en_rx_skb(struct mlx4_en_priv *priv,
struct mlx4_en_rx_desc *rx_desc,
struct mlx4_en_rx_alloc *frags,
unsigned int length)
{
@ -703,7 +702,6 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
struct mlx4_cqe *cqe;
struct mlx4_en_rx_ring *ring = priv->rx_ring[cq->ring];
struct mlx4_en_rx_alloc *frags;
struct mlx4_en_rx_desc *rx_desc;
struct bpf_prog *xdp_prog;
int doorbell_pending;
struct sk_buff *skb;
@ -738,7 +736,6 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
cq->mcq.cons_index & cq->size)) {
frags = ring->rx_info + (index << priv->log_rx_info);
rx_desc = ring->buf + (index << ring->log_stride);
/*
* make sure we read the CQE after we read the ownership bit
@ -767,7 +764,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
/* Get pointer to first fragment since we haven't
* skb yet and cast it to ethhdr struct
*/
dma = be64_to_cpu(rx_desc->data[0].addr);
dma = frags[0].dma + frags[0].page_offset;
dma_sync_single_for_cpu(priv->ddev, dma, sizeof(*ethh),
DMA_FROM_DEVICE);
ethh = (struct ethhdr *)(page_address(frags[0].page) +
@ -806,7 +803,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
void *orig_data;
u32 act;
dma = be64_to_cpu(rx_desc->data[0].addr);
dma = frags[0].dma + frags[0].page_offset;
dma_sync_single_for_cpu(priv->ddev, dma,
priv->frag_info[0].frag_size,
DMA_FROM_DEVICE);
@ -946,7 +943,7 @@ xdp_drop_no_cnt:
}
/* GRO not possible, complete processing here */
skb = mlx4_en_rx_skb(priv, rx_desc, frags, length);
skb = mlx4_en_rx_skb(priv, frags, length);
if (unlikely(!skb)) {
ring->dropped++;
goto next;