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authorAlexander Duyck <alexander.h.duyck@intel.com>2009-07-23 18:10:06 +0000
committerDavid S. Miller <davem@davemloft.net>2009-07-26 09:47:01 -0700
commit2d94d8ab76ea6c858c6e2eb0ab0403b00b031039 (patch)
treedb8f6f4b56dfd3261ea6ce018ba6f571f1c3ccbb
parent4703bf73bd5b0d43c3eb5b547398d4f62dc5d4e1 (diff)
igb: use buffer_info->dma instead of shinfo->nr_frags to determine unmap
This change makes it so that we use buffer_info->dma instead of shinfo->nr_frags to determine if we need to unmap a received skb. By doing this we can avoid a cache miss on small packets since the buffer_info structure should already be prefetched. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/igb/igb_main.c30
1 files changed, 18 insertions, 12 deletions
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 2ffb51d6c959..12d8683c231e 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -4538,6 +4538,20 @@ static inline void igb_rx_checksum_adv(struct igb_adapter *adapter,
adapter->hw_csum_good++;
}
+static inline u16 igb_get_hlen(struct igb_adapter *adapter,
+ union e1000_adv_rx_desc *rx_desc)
+{
+ /* HW will not DMA in data larger than the given buffer, even if it
+ * parses the (NFS, of course) header to be larger. In that case, it
+ * fills the header buffer and spills the rest into the page.
+ */
+ u16 hlen = (le16_to_cpu(rx_desc->wb.lower.lo_dword.hdr_info) &
+ E1000_RXDADV_HDRBUFLEN_MASK) >> E1000_RXDADV_HDRBUFLEN_SHIFT;
+ if (hlen > adapter->rx_ps_hdr_size)
+ hlen = adapter->rx_ps_hdr_size;
+ return hlen;
+}
+
static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring,
int *work_done, int budget)
{
@@ -4552,7 +4566,8 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring,
int cleaned_count = 0;
unsigned int total_bytes = 0, total_packets = 0;
unsigned int i;
- u32 length, hlen, staterr;
+ u32 staterr;
+ u16 length;
i = rx_ring->next_to_clean;
buffer_info = &rx_ring->buffer_info[i];
@@ -4589,17 +4604,8 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring,
goto send_up;
}
- /* HW will not DMA in data larger than the given buffer, even
- * if it parses the (NFS, of course) header to be larger. In
- * that case, it fills the header buffer and spills the rest
- * into the page.
- */
- hlen = (le16_to_cpu(rx_desc->wb.lower.lo_dword.hdr_info) &
- E1000_RXDADV_HDRBUFLEN_MASK) >> E1000_RXDADV_HDRBUFLEN_SHIFT;
- if (hlen > adapter->rx_ps_hdr_size)
- hlen = adapter->rx_ps_hdr_size;
-
- if (!skb_shinfo(skb)->nr_frags) {
+ if (buffer_info->dma) {
+ u16 hlen = igb_get_hlen(adapter, rx_desc);
pci_unmap_single(pdev, buffer_info->dma,
adapter->rx_ps_hdr_size,
PCI_DMA_FROMDEVICE);