Messages in this thread | | | Subject | Re: [PATCH 12/21] bridge: slight optimization of addr compare | From | Toshiaki Makita <> | Date | Mon, 23 Dec 2013 17:33:47 +0900 |
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On Mon, 2013-12-23 at 13:10 +0800, Ding Tianhong wrote: > Use the recently added and possibly more efficient > ether_addr_equal_unaligned to instead of memcmp. > > Cc: Stephen Hemminger <stephen@networkplumber.org> > Cc: David Miller <davem@davemloft.net> > Cc: bridge@lists.linux-foundation.org > Cc: netdev@vger.kernel.org > Signed-off-by: Wang Weidong <wangweidong1@huawei.com> > Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> > --- > net/bridge/br_stp_if.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c > index 656a6f3..04217d1 100644 > --- a/net/bridge/br_stp_if.c > +++ b/net/bridge/br_stp_if.c > @@ -229,7 +229,7 @@ bool br_stp_recalculate_bridge_id(struct net_bridge *br) > > list_for_each_entry(p, &br->port_list, list) { > if (addr == br_mac_zero || > - memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) > + !ether_addr_equal_unaligned(p->dev->dev_addr, addr) < 0) > addr = p->dev->dev_addr; > > }
We cannot do this change. !ether_addr_equal() isn't identical to memcmp(). memcmp() can return negative value but ether_addr_equal() cannot. br_stp_recalculate_bridge_id() is searching the smallest address among its ports. This change breaks it.
Thanks, Toshiaki Makita
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