Re: [PATCH 6/6] psi: introduce psi monitor

Peter Zijlstra
2018-12-17T16:22:39Z

On Fri, Dec 14, 2018 at 09:15:08AM -0800, Suren Baghdasaryan wrote:
> +ssize_t psi_trigger_parse(char *buf, size_t nbytes, enum psi_res res,
> + enum psi_states *state, u32 *threshold_us, u32 *win_sz_us)
> +{
> + bool some;
> + bool threshold_pct;
> + u32 threshold;
> + u32 win_sz;
> + char *p;
> +
> + p = strsep(&buf, " ");
> + if (p == NULL)
> + return -EINVAL;
> +
> + /* parse type */
> + if (!strcmp(p, "some"))
> + some = true;
> + else if (!strcmp(p, "full"))
> + some = false;
> + else
> + return -EINVAL;
> +
> + switch (res) {
> + case (PSI_IO):
> + *state = some ? PSI_IO_SOME : PSI_IO_FULL;
> + break;
> + case (PSI_MEM):
> + *state = some ? PSI_MEM_SOME : PSI_MEM_FULL;
> + break;
> + case (PSI_CPU):
> + if (!some)
> + return -EINVAL;
> + *state = PSI_CPU_SOME;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + while (isspace(*buf))
> + buf++;
> +
> + p = strsep(&buf, "%");
> + if (p == NULL)
> + return -EINVAL;
> +
> + if (buf == NULL) {
> + /* % sign was not found, threshold is specified in us */
> + buf = p;
> + p = strsep(&buf, " ");
> + if (p == NULL)
> + return -EINVAL;
> +
> + threshold_pct = false;
> + } else
> + threshold_pct = true;
> +
> + /* parse threshold */
> + if (kstrtouint(p, 0, &threshold))
> + return -EINVAL;
> +
> + while (isspace(*buf))
> + buf++;
> +
> + p = strsep(&buf, " ");
> + if (p == NULL)
> + return -EINVAL;
> +
> + /* Parse window size */
> + if (kstrtouint(p, 0, &win_sz))
> + return -EINVAL;
> +
> + /* Check window size */
> + if (win_sz < PSI_TRIG_MIN_WIN_US || win_sz > PSI_TRIG_MAX_WIN_US)
> + return -EINVAL;
> +
> + if (threshold_pct)
> + threshold = (threshold * win_sz) / 100;
> +
> + /* Check threshold */
> + if (threshold == 0 || threshold > win_sz)
> + return -EINVAL;
> +
> + *threshold_us = threshold;
> + *win_sz_us = win_sz;
> +
> + return 0;
> +}

How well has this thing been fuzzed? Custom string parser, yay!