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From: David Laight <David.Laight@ACULAB.COM>
To: 'Borislav Petkov' <bp@alien8.de>,
	Noah Goldstein <goldstein.w.n@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
	"edumazet@google.com" <edumazet@google.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"hpa@zytor.com" <hpa@zytor.com>,
	lkml <linux-kernel@vger.kernel.org>
Subject: RE: x86/csum: Remove unnecessary odd handling
Date: Thu, 29 Jun 2023 14:27:55 +0000	[thread overview]
Message-ID: <5b04b05ecd3e4111bb12ac0c7317933e@AcuMS.aculab.com> (raw)
In-Reply-To: <20230628091241.GAZJv5ie0xVGvnMKIM@fat_crate.local>

...
> > All csum kunit tests pass.

Last time I looked I couldn't see where generated IPv6
checksums get changed from 0x0000 (from ~csum_fold() using
adc) to 0xffff - which I think the protocol requires.

The trivial way to do this is to initialise the sum to 1
(instead or 0 or 0xffff) and then add 1 after the invert.

It doesn't matter (much) for IPv4 because 0x0000 is 'no checksum'
rather than 'invalid'.

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  parent reply	other threads:[~2023-06-29 14:28 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20230628020657.957880-1-goldstein.w.n@gmail.com>
2023-06-28  9:12 ` x86/csum: Remove unnecessary odd handling Borislav Petkov
2023-06-28 15:32   ` Noah Goldstein
2023-06-28 17:44     ` Linus Torvalds
2023-06-28 18:34       ` Noah Goldstein
2023-06-28 20:02         ` Linus Torvalds
2023-06-29 14:04   ` David Laight
2023-06-29 14:27   ` David Laight [this message]
2023-09-01 22:21 ` Noah Goldstein
2023-09-06 13:49   ` David Laight
2023-09-06 14:38   ` David Laight
2023-09-20 19:20     ` Noah Goldstein
2023-09-20 19:23 ` Noah Goldstein
2023-09-23  3:24   ` kernel test robot
2023-09-23 14:05     ` Noah Goldstein
2023-09-23 21:13       ` David Laight
2023-09-24 14:35         ` Noah Goldstein
2023-12-23 22:18           ` Noah Goldstein
2024-01-04 23:28             ` Noah Goldstein
2024-01-04 23:34               ` Dave Hansen
2024-01-04 23:36               ` Linus Torvalds
2024-01-05  0:33                 ` Linus Torvalds
2024-01-05 10:41                   ` David Laight
2024-01-05 16:12                     ` David Laight
2024-01-05 18:05                     ` Linus Torvalds
2024-01-05 23:52                       ` David Laight
2024-01-06  0:18                         ` Linus Torvalds
2024-01-06 10:26                           ` Eric Dumazet
2024-01-06 19:32                             ` Linus Torvalds
2024-01-07 12:11                             ` David Laight
2024-01-06 22:08                       ` David Laight
2024-01-07  1:09                         ` H. Peter Anvin
2024-01-07 11:44                           ` David Laight
2023-09-24 14:35 ` Noah Goldstein

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