Re: [PATCH v3 1/3] lib: add crc64 calculation routines
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: 2018-07-17 15:43:12
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On Tue, 2018-07-17 at 22:55 +0800, Coly Li wrote:
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.
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).
+u64 __pure crc64_update(u64 crc, const void *_p, size_t len);
For sake of consistency I would name _len as well.
+ * 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
+ * crc64table[256] is the lookup table of a table-driver 64bit CRC
Ditto.
+ * Copyright 2018 SUSE Linux. + * Author: Coly Li [off-list ref]
+ *
This (blank comment) line is not needed.
+u64 __pure crc64_update(u64 crc, const void *_p, size_t len)
_len ?
+ * Copyright 2018 SUSE Linux. + * Author: Coly Li [off-list ref]
+ *
Not needed line.
+#include <inttypes.h> +#include <stdio.h>
+ blank line? Would separate groups of headers logically.
+#include <linux/swab.h>
+static int64_t crc64_table[256] = {0,};
I guess {0} would work as well (no comma).
+ printf("#include <uapi/linux/types.h>\n");
+ printf("#include <linux/cache.h>\n\n");Do wee need these? CRC32 case seems fine without. -- Andy Shevchenko [off-list ref] Intel Finland Oy