From: Andi Kleen <andi@firstfloor.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 1/2] xfs: add CRC infrastructure
Date: Wed, 07 Nov 2012 08:21:27 -0800 [thread overview]
Message-ID: <m2ehk5qt88.fsf@firstfloor.org> (raw)
In-Reply-To: <1352295452-4726-2-git-send-email-david@fromorbit.com> (Dave Chinner's message of "Thu, 8 Nov 2012 00:37:31 +1100")
Dave Chinner <david@fromorbit.com> writes:
> + */
> +static inline __uint32_t
> +xfs_start_cksum(char *buffer, size_t length, unsigned long cksum_offset)
> +{
> + __uint32_t zero = 0;
> + __uint32_t crc;
> +
> + /* Calculate CRC up to the checksum. */
> + crc = crc32c(XFS_CRC_SEED, buffer, cksum_offset);
> +
> + /* Skip checksum field */
> + crc = crc32c(crc, &zero, sizeof(__u32));
> +
> + /* Calculate the rest of the CRC. */
> + return crc32c(crc, &buffer[cksum_offset + sizeof(__be32)],
> + length - (cksum_offset + sizeof(__be32)));
Don't you need to remap a zero result to some other value, otherwise a
real zero checksum will never be checked?
-Andi
--
ak@linux.intel.com -- Speaking for myself only
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next prev parent reply other threads:[~2012-11-07 16:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-07 13:37 [PATCH 0/2] xfs: CRCs for log buffers Dave Chinner
2012-11-07 13:37 ` [PATCH 1/2] xfs: add CRC infrastructure Dave Chinner
2012-11-07 16:21 ` Andi Kleen [this message]
2012-11-07 20:31 ` Dave Chinner
2012-11-07 21:39 ` Andi Kleen
2012-11-07 22:28 ` Dave Chinner
2012-11-08 14:42 ` Mark Tinguely
2012-11-08 21:22 ` Dave Chinner
2012-11-09 22:09 ` Mark Tinguely
2012-11-11 1:26 ` Dave Chinner
2012-11-11 19:54 ` Mark Tinguely
2012-11-11 22:51 ` Dave Chinner
2012-11-07 13:37 ` [PATCH 2/2] xfs: add CRC checks to the log Dave Chinner
2012-11-11 19:57 ` Mark Tinguely
2012-11-08 0:21 ` [PATCH 0/2] xfs: CRCs for log buffers Dave Chinner
2012-11-09 0:05 ` Ben Myers
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