linux-kernel - RE: RE: [PATCH v8 19/25] x86/resctrl: Auto assign/unassign counters when mbm_cntr

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Message-ID: <SJ1PR11MB6083379F790967B379C4232DFC442@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Mon, 14 Oct 2024 16:18:28 +0000
From: "Luck, Tony" <tony.luck@...el.com>
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Subject: RE: RE: [PATCH v8 19/25] x86/resctrl: Auto assign/unassign counters
 when mbm_cntr_assign is enabled

> >>>> +  if (!ret && is_mbm_local_enabled())
> >>>> +          ret = rdtgroup_assign_cntr_event(r, rdtgrp, NULL, QOS_L3_MBM_LOCAL_EVENT_ID);
> >
> > Now this call succeeds. The failure of the previous call is forgotten as "ret" is
> > overwritten with the success code.
>
> It will not make this call if the first call fails because of this check.
>
>         if (!ret && is_mbm_local_enabled())
>                 ret = rdtgroup_assign_cntr_event(r, rdtgrp, NULL,
> QOS_L3_MBM_LOCAL_EVENT_ID);
>
>         return ret;
>
> Here if (!1) evaluates to false.
>
> Did I miss something?

You didn't.

I missed the check for ret in the local case.

It is still the case that callers don't care about the return value.

-Tony