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From: Alexander Duyck <alexander.h.duyck@redhat.com>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net
Subject: [PATCH 3/3] etherdev: Use skb->data to retrieve Ethernet header instead of eth_hdr
Date: Thu, 30 Apr 2015 14:53:59 -0700	[thread overview]
Message-ID: <20150430215359.1798.79917.stgit@ahduyck-vm-fedora22> (raw)
In-Reply-To: <20150430214917.1798.49769.stgit@ahduyck-vm-fedora22>

Avoid recomputing the Ethernet header location and instead just use the
pointer provided by skb->data.  The problem with using eth_hdr is that the
compiler wasn't smart enough to realize that skb->head + skb->mac_header
was the same thing as skb->data before it added ETH_HLEN.  By just caching
it off before calling skb_pull_inline we can avoid a few unnecessary
instructions.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ethernet/eth.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 21c211e9fd5a..314e4c5a5a5e 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -156,8 +156,9 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
 
 	skb->dev = dev;
 	skb_reset_mac_header(skb);
+
+	eth = (struct ethhdr *)skb->data;
 	skb_pull_inline(skb, ETH_HLEN);
-	eth = eth_hdr(skb);
 
 	if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
 		if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))

  parent reply	other threads:[~2015-04-30 21:54 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-30 21:53 [PATCH 0/3] A few minor clean-ups to eth_type_trans Alexander Duyck
2015-04-30 21:53 ` [PATCH 1/3] etherdev: Avoid unnecessary byte swap in check for Ethertype Alexander Duyck
2015-04-30 23:03   ` Eric Dumazet
2015-04-30 23:24     ` Alexander Duyck
2015-05-01  0:13       ` Eric Dumazet
2015-05-01  0:41         ` Alexander Duyck
2015-04-30 21:53 ` [PATCH 2/3] etherdev: Process is_multicast_ether_addr at same size as other operations Alexander Duyck
2015-04-30 21:53 ` Alexander Duyck [this message]
2015-04-30 22:35 ` [PATCH 0/3] A few minor clean-ups to eth_type_trans Alexei Starovoitov
2015-04-30 23:11   ` Alexander Duyck
2015-05-01 11:30     ` David Laight
2015-05-01 15:34       ` Alexander Duyck
2015-05-04  2:47 ` David Miller

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