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Commit 8ba5366a authored by Steve Hodgson's avatar Steve Hodgson Committed by Ben Hutchings
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sfc: Reduce size of efx_rx_buffer by unionising skb and page 



[bwh: Forward-ported to net-next-2.6.]
Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
parent 5b2c4dd2

drivers/net/sfc/net_driver.h

+6 −2
Original line number Diff line number Diff line
@@ -216,13 +216,17 @@ struct efx_tx_queue { 
 *	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.

 */

struct efx_rx_buffer {

	dma_addr_t dma_addr;

	union {

		struct sk_buff *skb;

		struct page *page;

	} u;

	char *data;

	unsigned int len;

	bool is_page;

};



/**

drivers/net/sfc/rx.c

+45 −51
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue) 
	struct efx_nic *efx = rx_queue->efx;

	struct net_device *net_dev = efx->net_dev;

	struct efx_rx_buffer *rx_buf;

	struct sk_buff *skb;

	int skb_len = efx->rx_buffer_len;

	unsigned index, count;
@@ -136,24 +137,24 @@ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue) 
		index = rx_queue->added_count & rx_queue->ptr_mask;

		rx_buf = efx_rx_buffer(rx_queue, index);



		rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);

		if (unlikely(!rx_buf->skb))

		rx_buf->u.skb = skb = netdev_alloc_skb(net_dev, skb_len);

		if (unlikely(!skb))

			return -ENOMEM;

		rx_buf->page = NULL;



		/* Adjust the SKB for padding and checksum */

		skb_reserve(rx_buf->skb, NET_IP_ALIGN);

		skb_reserve(skb, NET_IP_ALIGN);

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

		rx_buf->len = skb_len - NET_IP_ALIGN;

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

		rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;

		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,

						  PCI_DMA_FROMDEVICE);

		if (unlikely(pci_dma_mapping_error(efx->pci_dev,

						   rx_buf->dma_addr))) {

			dev_kfree_skb_any(rx_buf->skb);

			rx_buf->skb = NULL;

			dev_kfree_skb_any(skb);

			rx_buf->u.skb = NULL;

			return -EIO;

		}
@@ -211,10 +212,10 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) 
		index = rx_queue->added_count & rx_queue->ptr_mask;

		rx_buf = efx_rx_buffer(rx_queue, index);

		rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;

		rx_buf->skb = NULL;

		rx_buf->page = page;

		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;

		++rx_queue->alloc_page_count;

		++state->refcnt;
@@ -235,19 +236,17 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue) 
static void efx_unmap_rx_buffer(struct efx_nic *efx,

				struct efx_rx_buffer *rx_buf)

{

	if (rx_buf->page) {

	if (rx_buf->is_page && rx_buf->u.page) {

		struct efx_rx_page_state *state;



		EFX_BUG_ON_PARANOID(rx_buf->skb);



		state = page_address(rx_buf->page);

		state = page_address(rx_buf->u.page);

		if (--state->refcnt == 0) {

			pci_unmap_page(efx->pci_dev,

				       state->dma_addr,

				       efx_rx_buf_size(efx),

				       PCI_DMA_FROMDEVICE);

		}

	} else if (likely(rx_buf->skb)) {

	} else if (!rx_buf->is_page && rx_buf->u.skb) {

		pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,

				 rx_buf->len, PCI_DMA_FROMDEVICE);

	}
@@ -256,12 +255,12 @@ static void efx_unmap_rx_buffer(struct efx_nic *efx, 
static void efx_free_rx_buffer(struct efx_nic *efx,

			       struct efx_rx_buffer *rx_buf)

{

	if (rx_buf->page) {

		__free_pages(rx_buf->page, efx->rx_buffer_order);

		rx_buf->page = NULL;

	} else if (likely(rx_buf->skb)) {

		dev_kfree_skb_any(rx_buf->skb);

		rx_buf->skb = NULL;

	if (rx_buf->is_page && rx_buf->u.page) {

		__free_pages(rx_buf->u.page, efx->rx_buffer_order);

		rx_buf->u.page = NULL;

	} else if (!rx_buf->is_page && rx_buf->u.skb) {

		dev_kfree_skb_any(rx_buf->u.skb);

		rx_buf->u.skb = NULL;

	}

}
@@ -277,7 +276,7 @@ static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue, 
static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue,

				    struct efx_rx_buffer *rx_buf)

{

	struct efx_rx_page_state *state = page_address(rx_buf->page);

	struct efx_rx_page_state *state = page_address(rx_buf->u.page);

	struct efx_rx_buffer *new_buf;

	unsigned fill_level, index;
@@ -292,16 +291,16 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue, 
	}



	++state->refcnt;

	get_page(rx_buf->page);

	get_page(rx_buf->u.page);



	index = rx_queue->added_count & rx_queue->ptr_mask;

	new_buf = efx_rx_buffer(rx_queue, index);

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

	new_buf->skb = NULL;

	new_buf->page = rx_buf->page;

	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;

}
@@ -315,16 +314,15 @@ static void efx_recycle_rx_buffer(struct efx_channel *channel, 
	struct efx_rx_buffer *new_buf;

	unsigned index;



	if (rx_buf->page != NULL && efx->rx_buffer_len <= EFX_RX_HALF_PAGE &&

	    page_count(rx_buf->page) == 1)

	if (rx_buf->is_page && efx->rx_buffer_len <= EFX_RX_HALF_PAGE &&

	    page_count(rx_buf->u.page) == 1)

		efx_resurrect_rx_buffer(rx_queue, rx_buf);



	index = rx_queue->added_count & rx_queue->ptr_mask;

	new_buf = efx_rx_buffer(rx_queue, index);



	memcpy(new_buf, rx_buf, sizeof(*new_buf));

	rx_buf->page = NULL;

	rx_buf->skb = NULL;

	rx_buf->u.page = NULL;

	++rx_queue->added_count;

}
@@ -428,7 +426,7 @@ static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue, 
		 * data at the end of the skb will be trashed. So

		 * we have no choice but to leak the fragment.

		 */

		*leak_packet = (rx_buf->skb != NULL);

		*leak_packet = !rx_buf->is_page;

		efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY);

	} else {

		if (net_ratelimit())
@@ -454,13 +452,12 @@ static void efx_rx_packet_gro(struct efx_channel *channel, 
	gro_result_t gro_result;



	/* Pass the skb/page into the GRO engine */

	if (rx_buf->page) {

	if (rx_buf->is_page) {

		struct efx_nic *efx = channel->efx;

		struct page *page = rx_buf->page;

		struct page *page = rx_buf->u.page;

		struct sk_buff *skb;



		EFX_BUG_ON_PARANOID(rx_buf->skb);

		rx_buf->page = NULL;

		rx_buf->u.page = NULL;



		skb = napi_get_frags(napi);

		if (!skb) {
@@ -487,11 +484,10 @@ static void efx_rx_packet_gro(struct efx_channel *channel, 


		gro_result = napi_gro_frags(napi);

	} else {

		struct sk_buff *skb = rx_buf->skb;

		struct sk_buff *skb = rx_buf->u.skb;



		EFX_BUG_ON_PARANOID(!skb);

		EFX_BUG_ON_PARANOID(!checksummed);

		rx_buf->skb = NULL;

		rx_buf->u.skb = NULL;



		gro_result = napi_gro_receive(napi, skb);

	}
@@ -514,8 +510,6 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, 


	rx_buf = efx_rx_buffer(rx_queue, index);

	EFX_BUG_ON_PARANOID(!rx_buf->data);

	EFX_BUG_ON_PARANOID(rx_buf->skb && rx_buf->page);

	EFX_BUG_ON_PARANOID(!(rx_buf->skb || rx_buf->page));



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

	 * EFX_RXD_HEAD_ROOM ensures that the slot we are using
@@ -587,32 +581,32 @@ void __efx_rx_packet(struct efx_channel *channel, 
		return;

	}



	if (rx_buf->skb) {

		prefetch(skb_shinfo(rx_buf->skb));

	if (!rx_buf->is_page) {

		skb = rx_buf->u.skb;



		prefetch(skb_shinfo(skb));



		skb_reserve(rx_buf->skb, efx->type->rx_buffer_hash_size);

		skb_put(rx_buf->skb, rx_buf->len);

		skb_reserve(skb, efx->type->rx_buffer_hash_size);

		skb_put(skb, rx_buf->len);



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

			rx_buf->skb->rxhash = efx_rx_buf_hash(rx_buf);

			skb->rxhash = efx_rx_buf_hash(rx_buf);



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

		 * at the ethernet header */

		rx_buf->skb->protocol = eth_type_trans(rx_buf->skb,

						       efx->net_dev);

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



		skb_record_rx_queue(rx_buf->skb, channel->channel);

		skb_record_rx_queue(skb, channel->channel);

	}



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

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

		efx_rx_packet_gro(channel, rx_buf, checksummed);

		return;

	}



	/* We now own the SKB */

	skb = rx_buf->skb;

	rx_buf->skb = NULL;

	EFX_BUG_ON_PARANOID(!skb);

	skb = rx_buf->u.skb;

	rx_buf->u.skb = NULL;



	/* Set the SKB flags */

	skb_checksum_none_assert(skb);