linux-kernel - Re: [PATCH v3 09/10] x86/resctrl: Add arch_has_{sparse,empty}

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Message-ID: <2f8d9fb3-da66-21ff-147b-d1f7deaaed73@intel.com>
Date:   Tue, 19 May 2020 11:55:02 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     James Morse <james.morse@....com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        H Peter Anvin <hpa@...or.com>,
        Babu Moger <Babu.Moger@....com>
Subject: Re: [PATCH v3 09/10] x86/resctrl: Add arch_has_{sparse,empty}_bitmaps
 to explain CAT differences

Hi James,

Thank you very much for adding the handling of empty bitmaps. This looks
good to me, just one comment ...

On 5/18/2020 6:19 AM, James Morse wrote:
> -bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
> +static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
>  {
>  	unsigned long first_bit, zero_bit, val;
>  	unsigned int cbm_len = r->cache.cbm_len;
> @@ -93,7 +95,8 @@ bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
>  		return false;
>  	}
>  
> -	if (val == 0 || val > r->default_ctrl) {
> +	if ((!r->cache.arch_has_empty_bitmaps && val == 0) ||
> +	    (val > r->default_ctrl)) {
>  		rdt_last_cmd_puts("Mask out of range\n");
>  		return false;

There is unnecessary parentheses around 'val > r->default_ctrl'

Reinette