[Intel-wired-lan] [next PATCH S63 4/6] i40e/i40evf: Break i40e_fetch_rx_buffer up to allow for reuse of frag code
Bimmy Pujari
bimmy.pujari at intel.com
Tue Mar 14 17:15:25 UTC 2017
From: Alexander Duyck <alexander.h.duyck at intel.com>
This patch is meant to clean up the code in preparation for us adding
support for build_skb. Specifically we deconstruct i40e_fetch_buffer into
several functions so that those functions can later be reused when we add a
path for build_skb.
Specifically with this change we split out the code for adding a page to an
exiting skb.
Signed-off-by: Alexander Duyck <alexander.h.duyck at intel.com>
Change-ID: Iab1efbab6b8b97cb60ab9fdd0be1d37a056a154d
---
Testing Hints:
The greatest risk with this patch is a memory leak of some sort.
I already caught one spot where I hadn't fully thought things out
in regards to the path where we don't support bulk page updates.
My advice would be to test on a RHEL 6.X kernel as well as a RHEL
7.X kernel as the 6.X won't support bulk page count updates while
the 7.3 and later kernels do.
drivers/net/ethernet/intel/i40e/i40e_txrx.c | 138 ++++++++++++--------------
drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 138 ++++++++++++--------------
2 files changed, 130 insertions(+), 146 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index d7c4e1e..433309f 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1687,61 +1687,23 @@ static bool i40e_can_reuse_rx_page(struct i40e_rx_buffer *rx_buffer)
* @size: packet length from rx_desc
*
* This function will add the data contained in rx_buffer->page to the skb.
- * This is done either through a direct copy if the data in the buffer is
- * less than the skb header size, otherwise it will just attach the page as
- * a frag to the skb.
+ * It will just attach the page as a frag to the skb.
*
- * The function will then update the page offset if necessary and return
- * true if the buffer can be reused by the adapter.
+ * The function will then update the page offset.
**/
static void i40e_add_rx_frag(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
struct sk_buff *skb,
unsigned int size)
{
- struct page *page = rx_buffer->page;
- unsigned char *va = page_address(page) + rx_buffer->page_offset;
#if (PAGE_SIZE < 8192)
unsigned int truesize = I40E_RXBUFFER_2048;
#else
- unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
+ unsigned int truesize = SKB_DATA_ALIGN(size);
#endif
- unsigned int pull_len;
-
- if (unlikely(skb_is_nonlinear(skb)))
- goto add_tail_frag;
-
- /* will the data fit in the skb we allocated? if so, just
- * copy it as it is pretty small anyway
- */
- if (size <= I40E_RX_HDR_SIZE) {
- memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
-
- /* page is to be freed, increase pagecnt_bias instead of
- * decreasing page count.
- */
- rx_buffer->pagecnt_bias++;
- return;
- }
-
- /* we need the header to contain the greater of either
- * ETH_HLEN or 60 bytes if the skb->len is less than
- * 60 for skb_pad.
- */
- pull_len = eth_get_headlen(va, I40E_RX_HDR_SIZE);
-
- /* align pull length to size of long to optimize
- * memcpy performance
- */
- memcpy(__skb_put(skb, pull_len), va, ALIGN(pull_len, sizeof(long)));
-
- /* update all of the pointers */
- va += pull_len;
- size -= pull_len;
-add_tail_frag:
- skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
- (unsigned long)va & ~PAGE_MASK, size, truesize);
+ skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
+ rx_buffer->page_offset, size, truesize);
/* page is being used so we must update the page offset */
#if (PAGE_SIZE < 8192)
@@ -1781,45 +1743,66 @@ static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,
}
/**
- * i40e_fetch_rx_buffer - Allocate skb and populate it
+ * i40e_construct_skb - Allocate skb and populate it
* @rx_ring: rx descriptor ring to transact packets on
* @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
- * data from the current receive descriptor, taking care to set up the skb
- * correctly, as well as handling calling the page recycle function if
- * necessary.
+ * This function allocates an skb. It then populates it with the page
+ * data from the current receive descriptor, taking care to set up the
+ * skb correctly.
*/
-static inline
-struct sk_buff *i40e_fetch_rx_buffer(struct i40e_ring *rx_ring,
- struct i40e_rx_buffer *rx_buffer,
- struct sk_buff *skb,
- unsigned int size)
+static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring,
+ struct i40e_rx_buffer *rx_buffer,
+ unsigned int size)
{
- if (likely(!skb)) {
- void *page_addr = page_address(rx_buffer->page) +
- rx_buffer->page_offset;
+ void *va = page_address(rx_buffer->page) + rx_buffer->page_offset;
+#if (PAGE_SIZE < 8192)
+ unsigned int truesize = I40E_RXBUFFER_2048;
+#else
+ unsigned int truesize = SKB_DATA_ALIGN(size);
+#endif
+ unsigned int headlen;
+ struct sk_buff *skb;
- /* prefetch first cache line of first page */
- prefetch(page_addr);
+ /* prefetch first cache line of first page */
+ prefetch(va);
#if L1_CACHE_BYTES < 128
- prefetch(page_addr + L1_CACHE_BYTES);
+ prefetch(va + L1_CACHE_BYTES);
#endif
- /* allocate a skb to store the frags */
- skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
- I40E_RX_HDR_SIZE,
- GFP_ATOMIC | __GFP_NOWARN);
- if (unlikely(!skb)) {
- rx_ring->rx_stats.alloc_buff_failed++;
- rx_buffer->pagecnt_bias++;
- return NULL;
- }
- }
+ /* allocate a skb to store the frags */
+ skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
+ I40E_RX_HDR_SIZE,
+ GFP_ATOMIC | __GFP_NOWARN);
+ if (unlikely(!skb))
+ return NULL;
+
+ /* Determine available headroom for copy */
+ headlen = size;
+ if (headlen > I40E_RX_HDR_SIZE)
+ headlen = eth_get_headlen(va, I40E_RX_HDR_SIZE);
- /* pull page into skb */
- i40e_add_rx_frag(rx_ring, rx_buffer, skb, size);
+ /* align pull length to size of long to optimize memcpy performance */
+ memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
+
+ /* update all of the pointers */
+ size -= headlen;
+ if (size) {
+ skb_add_rx_frag(skb, 0, rx_buffer->page,
+ rx_buffer->page_offset + headlen,
+ size, truesize);
+
+ /* buffer is used by skb, update page_offset */
+#if (PAGE_SIZE < 8192)
+ rx_buffer->page_offset ^= truesize;
+#else
+ rx_buffer->page_offset += truesize;
+#endif
+ } else {
+ /* buffer is unused, reset bias back to rx_buffer */
+ rx_buffer->pagecnt_bias++;
+ }
return skb;
}
@@ -1944,9 +1927,18 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
rx_buffer = i40e_get_rx_buffer(rx_ring, size);
- skb = i40e_fetch_rx_buffer(rx_ring, rx_buffer, skb, size);
- if (!skb)
+ /* retrieve a buffer from the ring */
+ if (skb)
+ i40e_add_rx_frag(rx_ring, rx_buffer, skb, size);
+ else
+ skb = i40e_construct_skb(rx_ring, rx_buffer, size);
+
+ /* exit if we failed to retrieve a buffer */
+ if (!skb) {
+ rx_ring->rx_stats.alloc_buff_failed++;
+ rx_buffer->pagecnt_bias++;
break;
+ }
i40e_put_rx_buffer(rx_ring, rx_buffer);
cleaned_count++;
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index 06b3779..95e383a 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -1045,61 +1045,23 @@ static bool i40e_can_reuse_rx_page(struct i40e_rx_buffer *rx_buffer)
* @size: packet length from rx_desc
*
* This function will add the data contained in rx_buffer->page to the skb.
- * This is done either through a direct copy if the data in the buffer is
- * less than the skb header size, otherwise it will just attach the page as
- * a frag to the skb.
+ * It will just attach the page as a frag to the skb.
*
- * The function will then update the page offset if necessary and return
- * true if the buffer can be reused by the adapter.
+ * The function will then update the page offset.
**/
static void i40e_add_rx_frag(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
struct sk_buff *skb,
unsigned int size)
{
- struct page *page = rx_buffer->page;
- unsigned char *va = page_address(page) + rx_buffer->page_offset;
#if (PAGE_SIZE < 8192)
unsigned int truesize = I40E_RXBUFFER_2048;
#else
- unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
+ unsigned int truesize = SKB_DATA_ALIGN(size);
#endif
- unsigned int pull_len;
-
- if (unlikely(skb_is_nonlinear(skb)))
- goto add_tail_frag;
-
- /* will the data fit in the skb we allocated? if so, just
- * copy it as it is pretty small anyway
- */
- if (size <= I40E_RX_HDR_SIZE) {
- memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
-
- /* page is to be freed, increase pagecnt_bias instead of
- * decreasing page count.
- */
- rx_buffer->pagecnt_bias++;
- return;
- }
-
- /* we need the header to contain the greater of either
- * ETH_HLEN or 60 bytes if the skb->len is less than
- * 60 for skb_pad.
- */
- pull_len = eth_get_headlen(va, I40E_RX_HDR_SIZE);
-
- /* align pull length to size of long to optimize
- * memcpy performance
- */
- memcpy(__skb_put(skb, pull_len), va, ALIGN(pull_len, sizeof(long)));
-
- /* update all of the pointers */
- va += pull_len;
- size -= pull_len;
-add_tail_frag:
- skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
- (unsigned long)va & ~PAGE_MASK, size, truesize);
+ skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
+ rx_buffer->page_offset, size, truesize);
/* page is being used so we must update the page offset */
#if (PAGE_SIZE < 8192)
@@ -1139,45 +1101,66 @@ static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,
}
/**
- * i40evf_fetch_rx_buffer - Allocate skb and populate it
+ * i40e_construct_skb - Allocate skb and populate it
* @rx_ring: rx descriptor ring to transact packets on
* @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
- * data from the current receive descriptor, taking care to set up the skb
- * correctly, as well as handling calling the page recycle function if
- * necessary.
+ * This function allocates an skb. It then populates it with the page
+ * data from the current receive descriptor, taking care to set up the
+ * skb correctly.
*/
-static inline
-struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,
- struct i40e_rx_buffer *rx_buffer,
- struct sk_buff *skb,
- unsigned int size)
+static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring,
+ struct i40e_rx_buffer *rx_buffer,
+ unsigned int size)
{
- if (likely(!skb)) {
- void *page_addr = page_address(rx_buffer->page) +
- rx_buffer->page_offset;
+ void *va = page_address(rx_buffer->page) + rx_buffer->page_offset;
+#if (PAGE_SIZE < 8192)
+ unsigned int truesize = I40E_RXBUFFER_2048;
+#else
+ unsigned int truesize = SKB_DATA_ALIGN(size);
+#endif
+ unsigned int headlen;
+ struct sk_buff *skb;
- /* prefetch first cache line of first page */
- prefetch(page_addr);
+ /* prefetch first cache line of first page */
+ prefetch(va);
#if L1_CACHE_BYTES < 128
- prefetch(page_addr + L1_CACHE_BYTES);
+ prefetch(va + L1_CACHE_BYTES);
#endif
- /* allocate a skb to store the frags */
- skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
- I40E_RX_HDR_SIZE,
- GFP_ATOMIC | __GFP_NOWARN);
- if (unlikely(!skb)) {
- rx_ring->rx_stats.alloc_buff_failed++;
- rx_buffer->pagecnt_bias++;
- return NULL;
- }
- }
+ /* allocate a skb to store the frags */
+ skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
+ I40E_RX_HDR_SIZE,
+ GFP_ATOMIC | __GFP_NOWARN);
+ if (unlikely(!skb))
+ return NULL;
+
+ /* Determine available headroom for copy */
+ headlen = size;
+ if (headlen > I40E_RX_HDR_SIZE)
+ headlen = eth_get_headlen(va, I40E_RX_HDR_SIZE);
- /* pull page into skb */
- i40e_add_rx_frag(rx_ring, rx_buffer, skb, size);
+ /* align pull length to size of long to optimize memcpy performance */
+ memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
+
+ /* update all of the pointers */
+ size -= headlen;
+ if (size) {
+ skb_add_rx_frag(skb, 0, rx_buffer->page,
+ rx_buffer->page_offset + headlen,
+ size, truesize);
+
+ /* buffer is used by skb, update page_offset */
+#if (PAGE_SIZE < 8192)
+ rx_buffer->page_offset ^= truesize;
+#else
+ rx_buffer->page_offset += truesize;
+#endif
+ } else {
+ /* buffer is unused, reset bias back to rx_buffer */
+ rx_buffer->pagecnt_bias++;
+ }
return skb;
}
@@ -1297,9 +1280,18 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
rx_buffer = i40e_get_rx_buffer(rx_ring, size);
- skb = i40evf_fetch_rx_buffer(rx_ring, rx_buffer, skb, size);
- if (!skb)
+ /* retrieve a buffer from the ring */
+ if (skb)
+ i40e_add_rx_frag(rx_ring, rx_buffer, skb, size);
+ else
+ skb = i40e_construct_skb(rx_ring, rx_buffer, size);
+
+ /* exit if we failed to retrieve a buffer */
+ if (!skb) {
+ rx_ring->rx_stats.alloc_buff_failed++;
+ rx_buffer->pagecnt_bias++;
break;
+ }
i40e_put_rx_buffer(rx_ring, rx_buffer);
cleaned_count++;
--
2.4.11
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