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Date: Fri, 27 Dec 2013 21:11:46 -0800 From: Joe Perches <joe@...ches.com> To: Ding Tianhong <dingtianhong@...wei.com> Cc: Eric Dumazet <eric.dumazet@...il.com>, Julia Lawall <julia.lawall@...6.fr>, "David S. Miller" <davem@...emloft.net>, Netdev <netdev@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH net-next 19/20] net: plip: slight optimization of addr compare On Sat, 2013-12-28 at 13:07 +0800, Ding Tianhong wrote: > On 2013/12/28 1:06, Joe Perches wrote: > > On Fri, 2013-12-27 at 07:48 -0800, Eric Dumazet wrote: > >> On Fri, 2013-12-27 at 14:49 +0800, Ding Tianhong wrote: > >>> Use possibly more efficient ether_addr_equal > >>> to instead of memcmp. > > [] > >>> diff --git a/drivers/net/plip/plip.c b/drivers/net/plip/plip.c > > [] > >>> @@ -549,7 +549,7 @@ static __be16 plip_type_trans(struct sk_buff *skb, struct net_device *dev) > >>> > >>> if(*eth->h_dest&1) > >>> { > >>> - if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0) > >>> + if(ether_addr_equal(eth->h_dest, dev->broadcast)) > >>> skb->pkt_type=PACKET_BROADCAST; > >>> else > >>> skb->pkt_type=PACKET_MULTICAST; > >> > >> What about : > >> > >> if (is_multicast_ether_addr(eth->h_dest)) { > >> if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast)) > >> skb->pkt_type = PACKET_BROADCAST; > >> else > >> skb->pkt_type = PACKET_MULTICAST; > >> } > > > > That is better though I wonder how many systems are > > still using laplink via parallel null-printer cables. > > > > No matter, better is better. > > > > The same optimization using ether_addr_equal_64bits > > may be possible to do in other places given other > > structs too. > > > > Perhaps it's a possible spatch/coccinelle conversion, > > > > I don't know spatch well enough to know if a > > mechanism to check if structure members have other > > fields that follow them in the structure or if the > > structure member is an array of a minimum size. > > > > Maybe Julia does. (cc'd) > > > > > As the below patch said, that a lot of ether_addr_equal > could be instead of ether_addr_equal_64bits, and I need to > review them and resend. I don't think so. I think what you've done so far is fine. Any conversions to ether_addr_equal_64bit can be done later. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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