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Commit a526f140 authored by Steve Hodgson's avatar Steve Hodgson Committed by Ben Hutchings
Browse files

sfc: Reduce size of efx_rx_buffer further by removing data member 



Instead calculate the KVA of receive data. It's not like it's a hard sum.

[bwh: Fixed to work with GRO.]
Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
parent 8ba5366a

drivers/net/sfc/net_driver.h

+0 −2
Original line number Diff line number Diff line
@@ -214,7 +214,6 @@ struct efx_tx_queue { 
 *	If both this and page are %NULL, the buffer slot is currently free.

 * @page: The associated page buffer, if any.

 *	If both this and skb are %NULL, the buffer slot is currently free.

 * @data: Pointer to ethernet header

 * @len: Buffer length, in bytes.

 * @is_page: Indicates if @page is valid. If false, @skb is valid.

 */
@@ -224,7 +223,6 @@ struct efx_rx_buffer { 
		struct sk_buff *skb;

		struct page *page;

	} u;

	char *data;

	unsigned int len;

	bool is_page;

};

drivers/net/sfc/rx.c

+28 −22
Original line number Diff line number Diff line
@@ -89,24 +89,37 @@ static unsigned int rx_refill_limit = 95; 
 */

#define EFX_RXD_HEAD_ROOM 2



static inline unsigned int efx_rx_buf_offset(struct efx_rx_buffer *buf)

/* Offset of ethernet header within page */

static inline unsigned int efx_rx_buf_offset(struct efx_nic *efx,

					     struct efx_rx_buffer *buf)

{

	/* Offset is always within one page, so we don't need to consider

	 * the page order.

	 */

	return (__force unsigned long) buf->data & (PAGE_SIZE - 1);

	return (((__force unsigned long) buf->dma_addr & (PAGE_SIZE - 1)) +

		efx->type->rx_buffer_hash_size);

}

static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)

{

	return PAGE_SIZE << efx->rx_buffer_order;

}



static inline u32 efx_rx_buf_hash(struct efx_rx_buffer *buf)

static u8 *efx_rx_buf_eh(struct efx_nic *efx, struct efx_rx_buffer *buf)

{

	if (buf->is_page)

		return page_address(buf->u.page) + efx_rx_buf_offset(efx, buf);

	else

		return ((u8 *)buf->u.skb->data +

			efx->type->rx_buffer_hash_size);

}



static inline u32 efx_rx_buf_hash(const u8 *eh)

{

	/* The ethernet header is always directly after any hash. */

#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || NET_IP_ALIGN % 4 == 0

	return __le32_to_cpup((const __le32 *)(buf->data - 4));

	return __le32_to_cpup((const __le32 *)(eh - 4));

#else

	const u8 *data = (const u8 *)(buf->data - 4);

	const u8 *data = eh - 4;

	return ((u32)data[0]       |

		(u32)data[1] << 8  |

		(u32)data[2] << 16 |
@@ -143,13 +156,12 @@ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue) 


		/* Adjust the SKB for padding and checksum */

		skb_reserve(skb, NET_IP_ALIGN);

		rx_buf->data = (char *)skb->data;

		rx_buf->len = skb_len - NET_IP_ALIGN;

		rx_buf->is_page = false;

		skb->ip_summed = CHECKSUM_UNNECESSARY;



		rx_buf->dma_addr = pci_map_single(efx->pci_dev,

						  rx_buf->data, rx_buf->len,

						  skb->data, rx_buf->len,

						  PCI_DMA_FROMDEVICE);

		if (unlikely(pci_dma_mapping_error(efx->pci_dev,

						   rx_buf->dma_addr))) {
@@ -213,7 +225,6 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) 
		rx_buf = efx_rx_buffer(rx_queue, index);

		rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;

		rx_buf->u.page = page;

		rx_buf->data = page_addr + EFX_PAGE_IP_ALIGN;

		rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;

		rx_buf->is_page = true;

		++rx_queue->added_count;
@@ -297,8 +308,6 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue, 
	new_buf = efx_rx_buffer(rx_queue, index);

	new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1);

	new_buf->u.page = rx_buf->u.page;

	new_buf->data = (void *)

		((__force unsigned long)rx_buf->data ^ (PAGE_SIZE >> 1));

	new_buf->len = rx_buf->len;

	new_buf->is_page = true;

	++rx_queue->added_count;
@@ -446,7 +455,7 @@ static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue, 
 */

static void efx_rx_packet_gro(struct efx_channel *channel,

			      struct efx_rx_buffer *rx_buf,

			      bool checksummed)

			      const u8 *eh, bool checksummed)

{

	struct napi_struct *napi = &channel->napi_str;

	gro_result_t gro_result;
@@ -466,11 +475,11 @@ static void efx_rx_packet_gro(struct efx_channel *channel, 
		}



		if (efx->net_dev->features & NETIF_F_RXHASH)

			skb->rxhash = efx_rx_buf_hash(rx_buf);

			skb->rxhash = efx_rx_buf_hash(eh);



		skb_shinfo(skb)->frags[0].page = page;

		skb_shinfo(skb)->frags[0].page_offset =

			efx_rx_buf_offset(rx_buf);

			efx_rx_buf_offset(efx, rx_buf);

		skb_shinfo(skb)->frags[0].size = rx_buf->len;

		skb_shinfo(skb)->nr_frags = 1;
@@ -509,7 +518,6 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, 
	bool leak_packet = false;



	rx_buf = efx_rx_buffer(rx_queue, index);

	EFX_BUG_ON_PARANOID(!rx_buf->data);



	/* This allows the refill path to post another buffer.

	 * EFX_RXD_HEAD_ROOM ensures that the slot we are using
@@ -548,12 +556,12 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, 
	/* Prefetch nice and early so data will (hopefully) be in cache by

	 * the time we look at it.

	 */

	prefetch(rx_buf->data);

	prefetch(efx_rx_buf_eh(efx, rx_buf));



	/* Pipeline receives so that we give time for packet headers to be

	 * prefetched into cache.

	 */

	rx_buf->len = len;

	rx_buf->len = len - efx->type->rx_buffer_hash_size;

out:

	if (channel->rx_pkt)

		__efx_rx_packet(channel,
@@ -568,15 +576,13 @@ void __efx_rx_packet(struct efx_channel *channel, 
{

	struct efx_nic *efx = channel->efx;

	struct sk_buff *skb;



	rx_buf->data += efx->type->rx_buffer_hash_size;

	rx_buf->len -= efx->type->rx_buffer_hash_size;

	u8 *eh = efx_rx_buf_eh(efx, rx_buf);



	/* If we're in loopback test, then pass the packet directly to the

	 * loopback layer, and free the rx_buf here

	 */

	if (unlikely(efx->loopback_selftest)) {

		efx_loopback_rx_packet(efx, rx_buf->data, rx_buf->len);

		efx_loopback_rx_packet(efx, eh, rx_buf->len);

		efx_free_rx_buffer(efx, rx_buf);

		return;

	}
@@ -590,7 +596,7 @@ void __efx_rx_packet(struct efx_channel *channel, 
		skb_put(skb, rx_buf->len);



		if (efx->net_dev->features & NETIF_F_RXHASH)

			skb->rxhash = efx_rx_buf_hash(rx_buf);

			skb->rxhash = efx_rx_buf_hash(eh);



		/* Move past the ethernet header. rx_buf->data still points

		 * at the ethernet header */
@@ -600,7 +606,7 @@ void __efx_rx_packet(struct efx_channel *channel, 
	}



	if (likely(checksummed || rx_buf->is_page)) {

		efx_rx_packet_gro(channel, rx_buf, checksummed);

		efx_rx_packet_gro(channel, rx_buf, eh, checksummed);

		return;

	}