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Date: Thu, 16 Aug 2012 15:48:36 -0700
From: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@...el.com>
To: davem@...emloft.net
Cc: Alexander Duyck <alexander.h.duyck@...el.com>,
netdev@...r.kernel.org, gospo@...hat.com, sassmann@...hat.com,
Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@...el.com>
Subject: [net-next 7/9] ixgbe: Make allocating skb and placing data in it a separate function
From: Alexander Duyck <alexander.h.duyck@...el.com>
This patch creates a function named ixgbe_fetch_rx_buffer. The sole
purpose of this function is to retrieve a single buffer off of the ring and
to place it in an skb.
The advantage to doing this is that it helps improve the readability since
I can decrease the indentation and for the code in this section.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@...el.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@...el.com>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 166 ++++++++++++++------------
1 file changed, 89 insertions(+), 77 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index d11fac5..9e72ae6 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1693,6 +1693,89 @@ static bool ixgbe_add_rx_frag(struct ixgbe_ring *rx_ring,
return true;
}
+static struct sk_buff *ixgbe_fetch_rx_buffer(struct ixgbe_ring *rx_ring,
+ union ixgbe_adv_rx_desc *rx_desc)
+{
+ struct ixgbe_rx_buffer *rx_buffer;
+ struct sk_buff *skb;
+ struct page *page;
+
+ rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
+ page = rx_buffer->page;
+ prefetchw(page);
+
+ skb = rx_buffer->skb;
+
+ if (likely(!skb)) {
+ void *page_addr = page_address(page) +
+ rx_buffer->page_offset;
+
+ /* prefetch first cache line of first page */
+ prefetch(page_addr);
+#if L1_CACHE_BYTES < 128
+ prefetch(page_addr + L1_CACHE_BYTES);
+#endif
+
+ /* allocate a skb to store the frags */
+ skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
+ IXGBE_RX_HDR_SIZE);
+ if (unlikely(!skb)) {
+ rx_ring->rx_stats.alloc_rx_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);
+
+ /*
+ * Delay unmapping of the first packet. It carries the
+ * header information, HW may still access the header
+ * after the writeback. Only unmap it when EOP is
+ * reached
+ */
+ if (likely(ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)))
+ goto dma_sync;
+
+ IXGBE_CB(skb)->dma = rx_buffer->dma;
+ } else {
+ if (ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))
+ ixgbe_dma_sync_frag(rx_ring, skb);
+
+dma_sync:
+ /* 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,
+ ixgbe_rx_bufsz(rx_ring),
+ DMA_FROM_DEVICE);
+ }
+
+ /* pull page into skb */
+ if (ixgbe_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
+ /* hand second half of page back to the ring */
+ ixgbe_reuse_rx_page(rx_ring, rx_buffer);
+ } else if (IXGBE_CB(skb)->dma == rx_buffer->dma) {
+ /* the page has been released from the ring */
+ IXGBE_CB(skb)->page_released = true;
+ } else {
+ /* we are not reusing the buffer so unmap it */
+ dma_unmap_page(rx_ring->dev, rx_buffer->dma,
+ ixgbe_rx_pg_size(rx_ring),
+ DMA_FROM_DEVICE);
+ }
+
+ /* clear contents of buffer_info */
+ rx_buffer->skb = NULL;
+ rx_buffer->dma = 0;
+ rx_buffer->page = NULL;
+
+ return skb;
+}
+
/**
* ixgbe_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
* @q_vector: structure containing interrupt and ring information
@@ -1718,11 +1801,8 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
u16 cleaned_count = ixgbe_desc_unused(rx_ring);
do {
- struct ixgbe_rx_buffer *rx_buffer;
union ixgbe_adv_rx_desc *rx_desc;
struct sk_buff *skb;
- struct page *page;
- u16 ntc;
/* return some buffers to hardware, one at a time is too slow */
if (cleaned_count >= IXGBE_RX_BUFFER_WRITE) {
@@ -1730,9 +1810,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
cleaned_count = 0;
}
- ntc = rx_ring->next_to_clean;
- rx_desc = IXGBE_RX_DESC(rx_ring, ntc);
- rx_buffer = &rx_ring->rx_buffer_info[ntc];
+ rx_desc = IXGBE_RX_DESC(rx_ring, rx_ring->next_to_clean);
if (!ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_DD))
break;
@@ -1744,78 +1822,12 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
*/
rmb();
- page = rx_buffer->page;
- prefetchw(page);
-
- skb = rx_buffer->skb;
-
- if (likely(!skb)) {
- void *page_addr = page_address(page) +
- rx_buffer->page_offset;
-
- /* prefetch first cache line of first page */
- prefetch(page_addr);
-#if L1_CACHE_BYTES < 128
- prefetch(page_addr + L1_CACHE_BYTES);
-#endif
-
- /* allocate a skb to store the frags */
- skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
- IXGBE_RX_HDR_SIZE);
- if (unlikely(!skb)) {
- rx_ring->rx_stats.alloc_rx_buff_failed++;
- break;
- }
-
- /*
- * 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);
-
- /*
- * Delay unmapping of the first packet. It carries the
- * header information, HW may still access the header
- * after the writeback. Only unmap it when EOP is
- * reached
- */
- if (likely(ixgbe_test_staterr(rx_desc,
- IXGBE_RXD_STAT_EOP)))
- goto dma_sync;
+ /* retrieve a buffer from the ring */
+ skb = ixgbe_fetch_rx_buffer(rx_ring, rx_desc);
- IXGBE_CB(skb)->dma = rx_buffer->dma;
- } else {
- if (ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))
- ixgbe_dma_sync_frag(rx_ring, skb);
-
-dma_sync:
- /* 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,
- ixgbe_rx_bufsz(rx_ring),
- DMA_FROM_DEVICE);
- }
-
- /* pull page into skb */
- if (ixgbe_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
- /* hand second half of page back to the ring */
- ixgbe_reuse_rx_page(rx_ring, rx_buffer);
- } else if (IXGBE_CB(skb)->dma == rx_buffer->dma) {
- /* the page has been released from the ring */
- IXGBE_CB(skb)->page_released = true;
- } else {
- /* we are not reusing the buffer so unmap it */
- dma_unmap_page(rx_ring->dev, rx_buffer->dma,
- ixgbe_rx_pg_size(rx_ring),
- DMA_FROM_DEVICE);
- }
-
- /* clear contents of buffer_info */
- rx_buffer->skb = NULL;
- rx_buffer->dma = 0;
- rx_buffer->page = NULL;
+ /* exit if we failed to retrieve a buffer */
+ if (!skb)
+ break;
ixgbe_get_rsc_cnt(rx_ring, rx_desc, skb);
--
1.7.11.2
--
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