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i40e/i40evf: Limit DMA sync of RX buffers to actual packet size
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On packet RX, we perform a DMA sync for CPU before passing the
packet up.  Here we limit that sync to the actual length of the
incoming packet, rather than always syncing the entire buffer.

Change-ID: I626aaf6c37275a8ce9e81efcaa773f327b331487
Signed-off-by: Scott Peterson <scott.d.peterson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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Scott Peterson authored and Jeff Kirsher committed Feb 12, 2017
1 parent e5f77f4 commit 7987dcd
Showing 2 changed files with 18 additions and 14 deletions.
16 changes: 9 additions & 7 deletions drivers/net/ethernet/intel/i40e/i40e_txrx.c
View file
Original file line number Diff line number Diff line change
@@ -1525,7 +1525,7 @@ static inline bool i40e_page_is_reserved(struct page *page)
* i40e_add_rx_frag - Add contents of Rx buffer to sk_buff
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: buffer containing page to add
* @rx_desc: descriptor containing length of buffer written by hardware
* @size: packet length from rx_desc
* @skb: sk_buff to place the data into
*
* This function will add the data contained in rx_buffer->page to the skb.
@@ -1538,13 +1538,10 @@ static inline bool i40e_page_is_reserved(struct page *page)
**/
static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
union i40e_rx_desc *rx_desc,
unsigned int size,
struct sk_buff *skb)
{
struct page *page = rx_buffer->page;
u64 qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
unsigned int size = (qword & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
#if (PAGE_SIZE < 8192)
unsigned int truesize = I40E_RXBUFFER_2048;
#else
@@ -1613,6 +1610,11 @@ static inline
struct sk_buff *i40e_fetch_rx_buffer(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc)
{
u64 local_status_error_len =
le64_to_cpu(rx_desc->wb.qword1.status_error_len);
unsigned int size =
(local_status_error_len & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
struct i40e_rx_buffer *rx_buffer;
struct sk_buff *skb;
struct page *page;
@@ -1654,11 +1656,11 @@ struct sk_buff *i40e_fetch_rx_buffer(struct i40e_ring *rx_ring,
dma_sync_single_range_for_cpu(rx_ring->dev,
rx_buffer->dma,
rx_buffer->page_offset,
I40E_RXBUFFER_2048,
size,
DMA_FROM_DEVICE);

/* pull page into skb */
if (i40e_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
if (i40e_add_rx_frag(rx_ring, rx_buffer, size, skb)) {
/* hand second half of page back to the ring */
i40e_reuse_rx_page(rx_ring, rx_buffer);
rx_ring->rx_stats.page_reuse_count++;
16 changes: 9 additions & 7 deletions drivers/net/ethernet/intel/i40evf/i40e_txrx.c
View file
Original file line number Diff line number Diff line change
@@ -1003,7 +1003,7 @@ static inline bool i40e_page_is_reserved(struct page *page)
* i40e_add_rx_frag - Add contents of Rx buffer to sk_buff
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: buffer containing page to add
* @rx_desc: descriptor containing length of buffer written by hardware
* @size: packet length from rx_desc
* @skb: sk_buff to place the data into
*
* This function will add the data contained in rx_buffer->page to the skb.
@@ -1016,13 +1016,10 @@ static inline bool i40e_page_is_reserved(struct page *page)
**/
static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
union i40e_rx_desc *rx_desc,
unsigned int size,
struct sk_buff *skb)
{
struct page *page = rx_buffer->page;
u64 qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
unsigned int size = (qword & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
#if (PAGE_SIZE < 8192)
unsigned int truesize = I40E_RXBUFFER_2048;
#else
@@ -1091,6 +1088,11 @@ static inline
struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc)
{
u64 local_status_error_len =
le64_to_cpu(rx_desc->wb.qword1.status_error_len);
unsigned int size =
(local_status_error_len & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
struct i40e_rx_buffer *rx_buffer;
struct sk_buff *skb;
struct page *page;
@@ -1132,11 +1134,11 @@ struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,
dma_sync_single_range_for_cpu(rx_ring->dev,
rx_buffer->dma,
rx_buffer->page_offset,
I40E_RXBUFFER_2048,
size,
DMA_FROM_DEVICE);

/* pull page into skb */
if (i40e_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
if (i40e_add_rx_frag(rx_ring, rx_buffer, size, skb)) {
/* hand second half of page back to the ring */
i40e_reuse_rx_page(rx_ring, rx_buffer);
rx_ring->rx_stats.page_reuse_count++;

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