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Commit 9e8c0395 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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mlx4: do not access rx_desc from mlx4_en_process_rx_cq() 



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: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarTariq Toukan <tariqt@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7d7bfc6a

drivers/net/ethernet/mellanox/mlx4/en_rx.c

+3 −6
Original line number Diff line number Diff line
@@ -528,7 +528,6 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv, 




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 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud 
		}



		/* 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;