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Commit 4b62dce4 authored by Felix Fietkau's avatar Felix Fietkau Committed by David S. Miller
Browse files

bgmac: set received skb headroom to NET_SKB_PAD 



A packet buffer offset of 30 bytes is inefficient, because the first 2
bytes end up in a different cacheline.

Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent eb64e292

drivers/net/ethernet/broadcom/bgmac.c

+8 −6
Original line number Diff line number Diff line
@@ -346,13 +346,13 @@ static int bgmac_dma_rx_skb_for_slot(struct bgmac *bgmac, 
		return -ENOMEM;



	/* Poison - if everything goes fine, hardware will overwrite it */

	rx = buf;

	rx = buf + BGMAC_RX_BUF_OFFSET;

	rx->len = cpu_to_le16(0xdead);

	rx->flags = cpu_to_le16(0xbeef);



	/* Map skb for the DMA */

	dma_addr = dma_map_single(dma_dev, buf, BGMAC_RX_BUF_SIZE,

				  DMA_FROM_DEVICE);

	dma_addr = dma_map_single(dma_dev, buf + BGMAC_RX_BUF_OFFSET,

				  BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);

	if (dma_mapping_error(dma_dev, dma_addr)) {

		bgmac_err(bgmac, "DMA mapping error\n");

		put_page(virt_to_head_page(buf));
@@ -403,7 +403,7 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring, 
	while (ring->start != ring->end) {

		struct device *dma_dev = bgmac->core->dma_dev;

		struct bgmac_slot_info *slot = &ring->slots[ring->start];

		struct bgmac_rx_header *rx = slot->buf;

		struct bgmac_rx_header *rx = slot->buf + BGMAC_RX_BUF_OFFSET;

		struct sk_buff *skb;

		void *buf = slot->buf;

		u16 len, flags;
@@ -454,8 +454,10 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring, 
					 BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);



			skb = build_skb(buf, BGMAC_RX_ALLOC_SIZE);

			skb_put(skb, BGMAC_RX_FRAME_OFFSET + len);

			skb_pull(skb, BGMAC_RX_FRAME_OFFSET);

			skb_put(skb, BGMAC_RX_FRAME_OFFSET +

				BGMAC_RX_BUF_OFFSET + len);

			skb_pull(skb, BGMAC_RX_FRAME_OFFSET +

				 BGMAC_RX_BUF_OFFSET);



			skb_checksum_none_assert(skb);

			skb->protocol = eth_type_trans(skb, bgmac->net_dev);

drivers/net/ethernet/broadcom/bgmac.h

+3 −1
Original line number Diff line number Diff line
@@ -360,9 +360,11 @@ 


#define BGMAC_RX_HEADER_LEN			28		/* Last 24 bytes are unused. Well... */

#define BGMAC_RX_FRAME_OFFSET			30		/* There are 2 unused bytes between header and real data */

#define BGMAC_RX_BUF_OFFSET			(NET_SKB_PAD + NET_IP_ALIGN - \

						 BGMAC_RX_FRAME_OFFSET)

#define BGMAC_RX_MAX_FRAME_SIZE			1536		/* Copied from b44/tg3 */

#define BGMAC_RX_BUF_SIZE			(BGMAC_RX_FRAME_OFFSET + BGMAC_RX_MAX_FRAME_SIZE)

#define BGMAC_RX_ALLOC_SIZE			(SKB_DATA_ALIGN(BGMAC_RX_BUF_SIZE) + \

#define BGMAC_RX_ALLOC_SIZE			(SKB_DATA_ALIGN(BGMAC_RX_BUF_SIZE + BGMAC_RX_BUF_OFFSET) + \

						 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))



#define BGMAC_BFL_ENETROBO			0x0010		/* has ephy roboswitch spi */