From: Joe Perches <joe@perches.com>
To: netdev@oss.sgi.com
Subject: Re: [IPX]: Fix checksum computation.
Date: Fri, 31 Oct 2003 13:24:06 -0800 [thread overview]
Message-ID: <1067635446.11564.92.camel@localhost.localdomain> (raw)
In-Reply-To: <200310312006.h9VK62Hh005910@hera.kernel.org>
On Thu, 2003-10-30 at 19:43, Linux Kernel Mailing List wrote:
> ChangeSet 1.1399, 2003/10/30 19:43:04-08:00, davem@nuts.ninka.net
> [IPX]: Fix checksum computation.
> diff -Nru a/net/appletalk/ddp.c b/net/appletalk/ddp.c
> --- a/net/appletalk/ddp.c Fri Oct 31 12:06:06 2003
> +++ b/net/appletalk/ddp.c Fri Oct 31 12:06:06 2003
> @@ -937,9 +937,13 @@
> {
> /* This ought to be unwrapped neatly. I'll trust gcc for now */
> while (len--) {
> - sum += *data++;
> + sum += *data;
> sum <<= 1;
> - sum = ((sum >> 16) + sum) & 0xFFFF;
> + if (sum & 0x10000) {
> + sum++;
> + sum &= 0xffff;
> + }
> + data++;
> }
> return sum;
> }
This change didn't appear on this list for comment,
it just appeared in the source.
Why is this a "fix"? Performance?
It seems more like someone's idea of code neatening.
If this is done, why not if (unlikely())
next parent reply other threads:[~2003-10-31 21:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200310312006.h9VK62Hh005910@hera.kernel.org>
2003-10-31 21:24 ` Joe Perches [this message]
2003-10-31 21:23 ` [IPX]: Fix checksum computation David S. Miller
2003-10-31 21:34 ` Arnaldo Carvalho de Melo
2003-10-31 21:50 ` Joe Perches
2003-10-31 21:53 ` David S. Miller
2003-10-31 22:21 ` Stephen Hemminger
2003-10-31 22:46 ` Arnaldo Carvalho de Melo
2003-11-01 0:25 ` David S. Miller
2003-10-31 21:56 ` Arnaldo Carvalho de Melo
2003-10-31 23:29 ` Mark Huth
2003-11-01 0:31 ` Joe Perches
2003-11-01 0:31 ` David S. Miller
2003-10-31 21:31 ` Arnaldo Carvalho de Melo
2003-11-01 0:38 ` Stephen Hemminger
2003-11-01 1:13 ` Arnaldo Carvalho de Melo
2003-11-01 1:19 ` Arnaldo Carvalho de Melo
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