On 2018/7/18 1:11 AM, Andy Shevchenko wrote:
> On Tue, Jul 17, 2018 at 5:55 PM, Coly Li <colyli@xxxxxxx> wrote:
>> This patch adds a kernel module to test the consistency of multiple crc
>> calculation in Linux kernel. It is enabled with CONFIG_TEST_CRC enabled.
>>
>> The test results are printed into kernel message, which look like,
>>
>> test_crc: crc64: PASSED (0x4e6b1ff972fa8c55, expected 0x4e6b1ff972fa8c55)
>> test_crc: crc64_bch: PASSED (0x0e4f1391d7a4a62e, expected 0x0e4f1391d7a4a62e)
>> test_crc: crc64_update: FAILED (0x03d4d0d85685d9a1, expected 0x3d4d0d85685d9a1f)
>>
>> kernel 0day system has framework to check kernel message, then the above
>> result can be handled by 0day system. If crc calculation inconsistency
>> happens, it can be detected quite soon.
>>
>> lib/test_crc.c is a testing frame work for many crc consistency
>> testings. For now, there are only test caes for 3 crc routines,
>> - crc64()
>> - crc64_bch()
>> - crc64_update()
>
> Thanks for an update. My comments below.
>
>> Changelog:
>> v3: Add test cases passed/failed statistic
>> More fixes for review comments of v2
>> v2: Fixes for review comments of v1
>> v1: Initial version.
>
> Usually this part goes after --- line below.
>
OK, I change all the patches in this way.
>> Signed-off-by: Coly Li <colyli@xxxxxxx>
>> Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
>
> Please, Cc me as well this one in next version (use my Intel address).
>
Added :-)
>> +#include <linux/async.h>
>> +#include <linux/delay.h>
>> +#include <linux/fs.h>
>> +#include <linux/list.h>
>> +#include <linux/module.h>
>> +#include <linux/printk.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/slab.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/crc64.h>
>
> Do we need all of them?
>
I remove most of them, only keep linux/module.h and linux/crc64.h in v4
series.
>> +static int chk_and_msg(const char *name, u64 crc, u64 expval)
>> +{
>
>> + int ret = 0;
>> +
>> + if (crc == expval) {
>
>> + pr_info("test_crc: %s: PASSED:(0x%016llx, expected 0x%016llx)\n",
>> + name, crc, expval);
>
> This doesn't bring anything useful.
>
>> + } else {
>> + pr_err("test_crc: %s: FAILED:(0x%016llx, expected 0x%016llx)\n",
>> + name, crc, expval);
>> + ret = -EINVAL;
>> + }
>> +
>> + return ret;
>
> I would rewrite entire function as follows:
>
> static void ...(...)
> {
> total_tests++;
> if (crc == expval)
> return;
>
> pr_err(...);
> failed_tests++;
> }
>
>
>> +}
>
>> +static int __init test_crc_init(void)
>> +{
>> + int i;
>> + int v, err = 0;
>> +
>> + pr_info("Kernel CRC consitency testing:\n");
>
>> + for (i = 0; test_data[i].name; i++) {
>> + v = test_data[i].handler(&test_data[i]);
>> + if (v < 0)
>> + err++;
>> + }
>
> ...and correct this to simple
> for (...)
> test_data[i].handler(...);
>
>> + if (err == 0)
>> + pr_info("test_crc: all %d tests passed\n", i);
>> + else
>> + pr_err("test_crc: %d cases tested, %d passed, %d failed\n",
>> + i, i - err, err);
>
> ...and this accordingly.
>
> Note, that in the future someone can add more test cases one or more
> of which could not map 1:1 to i here.
> That's why the rationale to have two global variables for test statistics.
> Also it allows (as you see above) to get rid of return code from all
> of those test. We don't interested in them I believe.
Yes, your code is simpler and more elegant IMHO. I change the code as
you suggested in v4 series.
Thanks.
Coly Li
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