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tg3: Use NET_IP_ALIGN

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This patch replaces hardcoded 2's with the NET_IP_ALIGN constant or
TG3_RAW_IP_ALIGN where appropriate.  Some platforms can redefine the
NET_IP_ALIGN definition to zero if unaligned DMA transfers cost more
than the IP header alignment gains.  This patch represents a
performance improvement when using the 5701 on these platforms.
The copy path can be avoided.

TG3_RAW_IP_ALIGN is used in cases where we always want to align the
IP header on dword boundaries.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matt Carlson 2008-11-21 17:16:16 -08:00 committed by David S. Miller
parent cf005b1d0e
commit ad8292681a
1 changed files with 13 additions and 7 deletions
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20
drivers/net/tg3.c
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@ -132,6 +132,8 @@
/* minimum number of free TX descriptors required to wake up TX process */
#define TG3_TX_WAKEUP_THRESH(tp) ((tp)->tx_pending / 4)
#define TG3_RAW_IP_ALIGN 2
/* number of ETHTOOL_GSTATS u64's */
#define TG3_NUM_STATS (sizeof(struct tg3_ethtool_stats)/sizeof(u64))
@ -4231,12 +4233,15 @@ static int tg3_rx(struct tg3 *tp, int budget)
goto next_pkt;
}
len = ((desc->idx_len & RXD_LEN_MASK) >> RXD_LEN_SHIFT) - 4; /* omit crc */
len = ((desc->idx_len & RXD_LEN_MASK) >> RXD_LEN_SHIFT) -
ETH_FCS_LEN;
if (len > RX_COPY_THRESHOLD
&& tp->rx_offset == 2
/* rx_offset != 2 iff this is a 5701 card running
* in PCI-X mode [see tg3_get_invariants()] */
&& tp->rx_offset == NET_IP_ALIGN
/* rx_offset will likely not equal NET_IP_ALIGN
* if this is a 5701 card running in PCI-X mode
* [see tg3_get_invariants()]
*/
) {
int skb_size;
@ -4256,11 +4261,12 @@ static int tg3_rx(struct tg3 *tp, int budget)
tg3_recycle_rx(tp, opaque_key,
desc_idx, *post_ptr);
copy_skb = netdev_alloc_skb(tp->dev, len + 2);
copy_skb = netdev_alloc_skb(tp->dev,
len + TG3_RAW_IP_ALIGN);
if (copy_skb == NULL)
goto drop_it_no_recycle;
skb_reserve(copy_skb, 2);
skb_reserve(copy_skb, TG3_RAW_IP_ALIGN);
skb_put(copy_skb, len);
pci_dma_sync_single_for_cpu(tp->pdev, dma_addr, len, PCI_DMA_FROMDEVICE);
skb_copy_from_linear_data(skb, copy_skb->data, len);
@ -12614,7 +12620,7 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
else
tp->tg3_flags &= ~TG3_FLAG_POLL_SERDES;
tp->rx_offset = 2;
tp->rx_offset = NET_IP_ALIGN;
if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5701 &&
(tp->tg3_flags & TG3_FLAG_PCIX_MODE) != 0)
tp->rx_offset = 0;