linux-kernel - Re: [PATCH 1/2] selftests/watchdog: limit ping loop and allow configuring the number of pings

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Message-Id: <20240703144855.89747-1-laura.nao@collabora.com>
Date: Wed,  3 Jul 2024 16:48:55 +0200
From: Laura Nao <laura.nao@...labora.com>
To: skhan@...uxfoundation.org
Cc: kernel@...labora.com,
	laura.nao@...labora.com,
	linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	shuah@...nel.org
Subject: Re: [PATCH 1/2] selftests/watchdog: limit ping loop and allow configuring the number of pings

On 6/27/24 20:48, Shuah Khan wrote:
> On 5/6/24 05:13, Laura Nao wrote:
>> In order to run the watchdog selftest with the kselftest runner, the
>> loop responsible for pinging the watchdog should be finite. This
>> change limits the loop to 5 iterations by default and introduces a new
>> '-c' option to adjust the number of pings as needed.
> 
> This patch makes the test run finite in all cases changing the bevavior
> to run it forever?

Correct.

>>
>> Signed-off-by: Laura Nao <laura.nao@...labora.com>
>> ---
>>   tools/testing/selftests/watchdog/watchdog-test.c | 16 ++++++++++++++--
>>   1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/testing/selftests/watchdog/watchdog-test.c 
>> b/tools/testing/selftests/watchdog/watchdog-test.c
>> index bc71cbca0dde..786cc5a26206 100644
>> --- a/tools/testing/selftests/watchdog/watchdog-test.c
>> +++ b/tools/testing/selftests/watchdog/watchdog-test.c
>> @@ -24,16 +24,18 @@
>>   #include <linux/watchdog.h>
>>   #define DEFAULT_PING_RATE    1
>> +#define DEFAULT_PING_COUNT    5
>>   int fd;
>>   const char v = 'V';
>> -static const char sopts[] = "bdehp:st:Tn:NLf:i";
>> +static const char sopts[] = "bdehp:c:st:Tn:NLf:i";
>>   static const struct option lopts[] = {
>>       {"bootstatus",          no_argument, NULL, 'b'},
>>       {"disable",             no_argument, NULL, 'd'},
>>       {"enable",              no_argument, NULL, 'e'},
>>       {"help",                no_argument, NULL, 'h'},
>>       {"pingrate",      required_argument, NULL, 'p'},
>> +    {"pingcount",     required_argument, NULL, 'c'},
>>       {"status",              no_argument, NULL, 's'},
>>       {"timeout",       required_argument, NULL, 't'},
>>       {"gettimeout",          no_argument, NULL, 'T'},
>> @@ -90,6 +92,8 @@ static void usage(char *progname)
>>       printf(" -h, --help\t\tPrint the help message\n");
>>       printf(" -p, --pingrate=P\tSet ping rate to P seconds (default 
>> %d)\n",
>>              DEFAULT_PING_RATE);
>> +    printf(" -c, --pingcount=C\tSet number of pings to C (default 
>> %d)\n",
>> +           DEFAULT_PING_COUNT);
>>       printf(" -t, --timeout=T\tSet timeout to T seconds\n");
>>       printf(" -T, --gettimeout\tGet the timeout\n");
>>       printf(" -n, --pretimeout=T\tSet the pretimeout to T seconds\n");
>> @@ -172,6 +176,7 @@ int main(int argc, char *argv[])
>>   {
>>       int flags;
>>       unsigned int ping_rate = DEFAULT_PING_RATE;
>> +    unsigned int ping_count = DEFAULT_PING_COUNT;
>>       int ret;
>>       int c;
>>       int oneshot = 0;
>> @@ -248,6 +253,12 @@ int main(int argc, char *argv[])
>>                   ping_rate = DEFAULT_PING_RATE;
>>               printf("Watchdog ping rate set to %u seconds.\n", 
>> ping_rate);
>>               break;
>> +        case 'c':
>> +            ping_count = strtoul(optarg, NULL, 0);
>> +            if (!ping_count)
>> +                ping_count = DEFAULT_PING_COUNT;
>> +            printf("Number of pings set to %u.\n", ping_count);
>> +            break;
>>           case 's':
>>               flags = 0;
>>               oneshot = 1;
>> @@ -336,9 +347,10 @@ int main(int argc, char *argv[])
>>       signal(SIGINT, term);
>> -    while (1) {
>> +    while (ping_count > 0) {
>>           keep_alive();
>>           sleep(ping_rate);
>> +        ping_count--;
> 
> So this test no longer runs forever?
>

That's correct, with this patch applied the test no longer runs forever. 
I understand you prefer the current behavior - how about keeping the
keep_alive() loop infinite by default and only making it finite when the 
-c argument is passed? Would that be reasonable?

Thanks for your feedback!

Laura