Re: [PATCH 5/8] x86/intel_rct/mba: Add MBA structures and initialize MBA

[Thomas Gleixner]

On Tue, 10 Jan 2017, Vikas Shivappa wrote:
> +static void rdt_get_mem_config(struct rdt_resource *r)
> +{
> +     union cpuid_0x10_3_eax eax;
> +     union cpuid_0x10_x_edx edx;
> +     u32 ebx, ecx;
> +
> +     cpuid_count(0x00000010, 3, &eax.full, &ebx, &ecx, &edx.full);
> +     r->num_closid = edx.split.cos_max + 1;
> +     r->max_delay = eax.split.max_delay + 1;
> +     r->no_ctrl = 0;
> +     if (ecx & MBE_IS_LINEAR)
> +             r->delay_linear = true;
> +
> +     if (r->delay_linear)
> +             r->delay_gran = MAX_MBA_THRTL - r->max_delay;

What's the point of this extra conditional?

        if (ecx & MBE_IS_LINEAR) {
                r->delay_linear = true;
                r->delay_gran = MAX_MBA_THRTL - r->max_delay;
        }       

would be too obvious and easy to understand, right?

> +static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
> +{
> +     int i;
> +
> +     d->ctrl_val = kmalloc_array(r->num_closid,
> +                                  sizeof(*d->ctrl_val), GFP_KERNEL);
> +     if (!d->ctrl_val) {
> +             kfree(d);

Freeing memory in the error path of some other random function is just wrong.

        if (!d->ctrl_val)
                return -ENOMEM;

and deal with the fallout at the calling function.

Thanks,

        tglx