On 2018/7/17 11:43 PM, Andy Shevchenko wrote:

On Tue, 2018-07-17 at 22:55 +0800, Coly Li wrote:

quoted

This patch adds the re-write crc64 calculation routines for Linux
kernel.
The CRC64 polynomical arithmetic follows ECMA-182 specification,
inspired
by CRC paper of Dr. Ross N. Williams
(see http://www.ross.net/crc/download/crc_v3.txt) and other public
domain
implementations.

All the changes work in this way,
- When Linux kernel is built, host program lib/gen_crc64table.c will
be
  compiled to lib/gen_crc64table and executed.
- The output of gen_crc64table execution is an array called as lookup
  table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64bits-long
  numbers, this talbe is dumped into header file lib/crc64table.h.
- Then the header file is included by lib/crc64.c for normal 64bit crc
  calculation.
- Function declaration of the crc64 calculation routines is placed in
  include/linux/crc64.h

Thanks for an update! My comments below.

quoted

Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

As required by coding style this tag should be accompanied with SoB of
co-developer(s).

Now I change the lines as following in commit log,
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

quoted

+u64 __pure crc64_update(u64 crc, const void *_p, size_t len);

For sake of consistency I would name _len as well.

Hmm, I will use 'p', and use '_p' for internal argument.

quoted

+ * Normal 64bit CRC calculation.

I think 64-bit form is slightly better and more often

$ git grep -n -w 64bit | wc -l
809

$ git grep -n -w 64-bit | wc -l
2957

quoted

+ * crc64table[256] is the lookup table of a table-driver 64bit CRC

Ditto.

Sure, I will change them to 64-bit.

quoted

+ * Copyright 2018 SUSE Linux.
+ *   Author: Coly Li [off-list ref]

quoted

+ *

This (blank comment) line is not needed.

quoted

+u64 __pure crc64_update(u64 crc, const void *_p, size_t len)

_len ?

I will rename '_p' to 'p' here too.

quoted

+ * Copyright 2018 SUSE Linux.
+ *   Author: Coly Li [off-list ref]

quoted

+ *

Not needed line.

Fixed in v4.

quoted

+#include <inttypes.h>
+#include <stdio.h>

+ blank line? Would separate groups of headers logically.

quoted

+#include <linux/swab.h>

quoted

+static int64_t crc64_table[256] = {0,};

I guess {0} would work as well (no comma).

Fixed them in v4.

quoted

+	printf("#include <uapi/linux/types.h>\n");
+	printf("#include <linux/cache.h>\n\n");

Do wee need these? CRC32 case seems fine without.

I renamed uapi/linux/types.h to linux/types.h, this header is for 'u64'.
Another header linux/cache.h is for '____cacheline_aligned'. They should
be necessary if these two headers are not included before
lib/crc64table.h is included.

Thanks for your review :-)

Coly Li