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Commit 9a064128 authored by Alexander Duyck's avatar Alexander Duyck Committed by Jeff Kirsher
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i40e/i40evf: Pull code for grabbing and syncing rx_buffer from fetch_buffer 



This patch pulls the code responsible for fetching the Rx buffer and
synchronizing DMA into a function, specifically called i40e_get_rx_buffer.

The general idea is to allow for better code reuse by pulling this out of
i40e_fetch_rx_buffer.  We dropped a couple of prefetches since the time
between the prefetch being called and the data being accessed was too small
to be useful.

Change-ID: I4885fce4b2637dbedc8e16431169d23d3d7e79b9
Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Tested-by: default avatarAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent d57c0e08

drivers/net/ethernet/intel/i40e/i40e_txrx.c

+34 −24
Original line number Diff line number Diff line
@@ -1753,10 +1753,36 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring, 
	return i40e_can_reuse_rx_page(rx_buffer, page, truesize);

}



/**

 * i40e_get_rx_buffer - Fetch Rx buffer and synchronize data for use

 * @rx_ring: rx descriptor ring to transact packets on

 * @size: size of buffer to add to skb

 *

 * This function will pull an Rx buffer from the ring and synchronize it

 * for use by the CPU.

 */

static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,

						 const unsigned int size)

{

	struct i40e_rx_buffer *rx_buffer;



	rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];

	prefetchw(rx_buffer->page);



	/* we are reusing so sync this buffer for CPU use */

	dma_sync_single_range_for_cpu(rx_ring->dev,

				      rx_buffer->dma,

				      rx_buffer->page_offset,

				      size,

				      DMA_FROM_DEVICE);



	return rx_buffer;

}



/**

 * i40e_fetch_rx_buffer - Allocate skb and populate it

 * @rx_ring: rx descriptor ring to transact packets on

 * @rx_desc: descriptor containing info written by hardware

 * @rx_buffer: rx buffer to pull data from

 * @size: size of buffer to add to skb

 *

 * This function allocates an skb on the fly, and populates it with the page
@@ -1766,19 +1792,13 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring, 
 */

static inline

struct sk_buff *i40e_fetch_rx_buffer(struct i40e_ring *rx_ring,

				     union i40e_rx_desc *rx_desc,

				     struct i40e_rx_buffer *rx_buffer,

				     struct sk_buff *skb,

				     unsigned int size)

{

	struct i40e_rx_buffer *rx_buffer;

	struct page *page;



	rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];

	page = rx_buffer->page;

	prefetchw(page);



	if (likely(!skb)) {

		void *page_addr = page_address(page) + rx_buffer->page_offset;

		void *page_addr = page_address(rx_buffer->page) +

				  rx_buffer->page_offset;



		/* prefetch first cache line of first page */

		prefetch(page_addr);
@@ -1794,21 +1814,8 @@ struct sk_buff *i40e_fetch_rx_buffer(struct i40e_ring *rx_ring, 
			rx_ring->rx_stats.alloc_buff_failed++;

			return NULL;

		}



		/* we will be copying header into skb->data in

		 * pskb_may_pull so it is in our interest to prefetch

		 * it now to avoid a possible cache miss

		 */

		prefetchw(skb->data);

	}



	/* we are reusing so sync this buffer for CPU use */

	dma_sync_single_range_for_cpu(rx_ring->dev,

				      rx_buffer->dma,

				      rx_buffer->page_offset,

				      size,

				      DMA_FROM_DEVICE);



	/* pull page into skb */

	if (i40e_add_rx_frag(rx_ring, rx_buffer, size, skb)) {

		/* hand second half of page back to the ring */
@@ -1886,6 +1893,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) 
	bool failure = false;



	while (likely(total_rx_packets < budget)) {

		struct i40e_rx_buffer *rx_buffer;

		union i40e_rx_desc *rx_desc;

		unsigned int size;

		u16 vlan_tag;
@@ -1918,7 +1926,9 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) 
		 */

		dma_rmb();



		skb = i40e_fetch_rx_buffer(rx_ring, rx_desc, skb, size);

		rx_buffer = i40e_get_rx_buffer(rx_ring, size);



		skb = i40e_fetch_rx_buffer(rx_ring, rx_buffer, skb, size);

		if (!skb)

			break;

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

+34 −24
Original line number Diff line number Diff line
@@ -1112,10 +1112,36 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring, 
	return i40e_can_reuse_rx_page(rx_buffer, page, truesize);

}



/**

 * i40e_get_rx_buffer - Fetch Rx buffer and synchronize data for use

 * @rx_ring: rx descriptor ring to transact packets on

 * @size: size of buffer to add to skb

 *

 * This function will pull an Rx buffer from the ring and synchronize it

 * for use by the CPU.

 */

static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,

						 const unsigned int size)

{

	struct i40e_rx_buffer *rx_buffer;



	rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];

	prefetchw(rx_buffer->page);



	/* we are reusing so sync this buffer for CPU use */

	dma_sync_single_range_for_cpu(rx_ring->dev,

				      rx_buffer->dma,

				      rx_buffer->page_offset,

				      size,

				      DMA_FROM_DEVICE);



	return rx_buffer;

}



/**

 * i40evf_fetch_rx_buffer - Allocate skb and populate it

 * @rx_ring: rx descriptor ring to transact packets on

 * @rx_desc: descriptor containing info written by hardware

 * @rx_buffer: rx buffer to pull data from

 * @size: size of buffer to add to skb

 *

 * This function allocates an skb on the fly, and populates it with the page
@@ -1125,19 +1151,13 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring, 
 */

static inline

struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,

				       union i40e_rx_desc *rx_desc,

				       struct i40e_rx_buffer *rx_buffer,

				       struct sk_buff *skb,

				       unsigned int size)

{

	struct i40e_rx_buffer *rx_buffer;

	struct page *page;



	rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];

	page = rx_buffer->page;

	prefetchw(page);



	if (likely(!skb)) {

		void *page_addr = page_address(page) + rx_buffer->page_offset;

		void *page_addr = page_address(rx_buffer->page) +

				  rx_buffer->page_offset;



		/* prefetch first cache line of first page */

		prefetch(page_addr);
@@ -1153,21 +1173,8 @@ struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring, 
			rx_ring->rx_stats.alloc_buff_failed++;

			return NULL;

		}



		/* we will be copying header into skb->data in

		 * pskb_may_pull so it is in our interest to prefetch

		 * it now to avoid a possible cache miss

		 */

		prefetchw(skb->data);

	}



	/* we are reusing so sync this buffer for CPU use */

	dma_sync_single_range_for_cpu(rx_ring->dev,

				      rx_buffer->dma,

				      rx_buffer->page_offset,

				      size,

				      DMA_FROM_DEVICE);



	/* pull page into skb */

	if (i40e_add_rx_frag(rx_ring, rx_buffer, size, skb)) {

		/* hand second half of page back to the ring */
@@ -1240,6 +1247,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) 
	bool failure = false;



	while (likely(total_rx_packets < budget)) {

		struct i40e_rx_buffer *rx_buffer;

		union i40e_rx_desc *rx_desc;

		unsigned int size;

		u16 vlan_tag;
@@ -1272,7 +1280,9 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) 
		 */

		dma_rmb();



		skb = i40evf_fetch_rx_buffer(rx_ring, rx_desc, skb, size);

		rx_buffer = i40e_get_rx_buffer(rx_ring, size);



		skb = i40evf_fetch_rx_buffer(rx_ring, rx_buffer, skb, size);

		if (!skb)

			break;