[Intel-wired-lan] [next PATCH S63 2/6] i40e/i40evf: Pull code for grabbing and syncing rx_buffer from fetch_buffer
Bimmy Pujari
bimmy.pujari at intel.com
Tue Mar 14 17:15:23 UTC 2017
From: Alexander Duyck <alexander.h.duyck at intel.com>
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.
Signed-off-by: Alexander Duyck <alexander.h.duyck at intel.com>
Change-ID: I4885fce4b2637dbedc8e16431169d23d3d7e79b9
---
Testing Hints:
Basic Rx testing should be enough to verify this is working
correctly.
drivers/net/ethernet/intel/i40e/i40e_txrx.c | 58 ++++++++++++++++-----------
drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 58 ++++++++++++++++-----------
2 files changed, 68 insertions(+), 48 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 68936b6..d1fc0f0 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1754,9 +1754,35 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
}
/**
+ * 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;
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index e41eb46..2320ec4 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -1113,9 +1113,35 @@ static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
}
/**
+ * 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;
--
2.4.11
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