Re: [PATCH v3 2/2] selftests/resctrl: Adjust SNC support messages

From: Maciej Wieczor-Retman
Date: Wed Jul 03 2024 - 02:51:00 EST


Thanks for the review,

On 2024-07-01 at 18:04:00 +0200, Luck, Tony wrote:
>+static bool cpus_offline_empty(void)
>+{
>+ char offline_cpus_str[64];
>+ FILE *fp;
>+
>+ fp = fopen("/sys/devices/system/cpu/offline", "r");
>
>Check for fp == NULL before using it.

Thanks, will add it.

>
>+ if (fscanf(fp, "%s", offline_cpus_str) < 0) {
>
>fscanf() seems like a heavy hammer.
>
> if (fgets(offline_cpus_str, sizeof(offline_cpus_str), fp) == NULL) {
>+ if (!errno) {
>
>Don't need an errno check (seems dubious mixing errno with stdio).

fscanf() returns "-1" when nothing was read as well as if there was an error.
But when nothing was read the errno is "0" instead of some error code so I could
differentiate the cases that way. The fgetc() you settled on shouldn't have this
problem.

>
>+ fclose(fp);
>+ return 1;
>
> return true;
>
>+ }
>+ ksft_perror("Could not read offline CPUs file!");
>+ }
>+
>+ fclose(fp);
>+
>+ return 0;
>
> return false;
>+}
>

--
Kind regards
Maciej Wieczór-Retman