diff options
| author | Eric Dumazet <edumazet@google.com> | 2013-08-01 17:49:52 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-08-04 08:55:52 +0400 |
| commit | f27070158d6754765f2f5fd1617e8e42a0ea2318 (patch) | |
| tree | e203a11394a14d0a4659933e6210e7bfe0f50661 /drivers/net/usb/ax88179_178a.c | |
| parent | 0e76a3a587fc7abda2badf249053b427baad255e (diff) | |
| download | linux-f27070158d6754765f2f5fd1617e8e42a0ea2318.tar.xz | |
ax88179_178a: avoid copy of tx tcp packets
ax88179_tx_fixup() has quite complex code trying to push 8 bytes
of control data (len/mss), but fails to do it properly for TCP packets,
incurring an extra copy and point of memory allocation failure.
Lets use the simple and approved way.
dev->needed_headroom being 8, all frames should have 8 bytes of
headroom, so the extra copy should be unlikely anyway.
This patch should improve performance for TCP xmits.
Reported-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/usb/ax88179_178a.c')
| -rw-r--r-- | drivers/net/usb/ax88179_178a.c | 21 |
1 files changed, 4 insertions, 17 deletions
diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c index 5a468f317ca5..fb0caa289d0b 100644 --- a/drivers/net/usb/ax88179_178a.c +++ b/drivers/net/usb/ax88179_178a.c @@ -1169,31 +1169,18 @@ ax88179_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags) int frame_size = dev->maxpacket; int mss = skb_shinfo(skb)->gso_size; int headroom; - int tailroom; tx_hdr1 = skb->len; tx_hdr2 = mss; if (((skb->len + 8) % frame_size) == 0) tx_hdr2 |= 0x80008000; /* Enable padding */ - headroom = skb_headroom(skb); - tailroom = skb_tailroom(skb); + headroom = skb_headroom(skb) - 8; - if (!skb_header_cloned(skb) && - !skb_cloned(skb) && - (headroom + tailroom) >= 8) { - if (headroom < 8) { - skb->data = memmove(skb->head + 8, skb->data, skb->len); - skb_set_tail_pointer(skb, skb->len); - } - } else { - struct sk_buff *skb2; - - skb2 = skb_copy_expand(skb, 8, 0, flags); + if ((skb_header_cloned(skb) || headroom < 0) && + pskb_expand_head(skb, headroom < 0 ? 8 : 0, 0, GFP_ATOMIC)) { dev_kfree_skb_any(skb); - skb = skb2; - if (!skb) - return NULL; + return NULL; } skb_push(skb, 4); |