linux-kernel - Re: [PATCH V3] arm64/cpufeature: Add get_arm64_ftr_reg

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Message-ID: <20200527113703.GD28101@gaia>
Date:   Wed, 27 May 2020 12:37:03 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, will@...nel.org,
        mark.rutland@....com, suzuki.poulose@....com,
        Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V3] arm64/cpufeature: Add get_arm64_ftr_reg_nowarn()

On Wed, May 27, 2020 at 03:34:36PM +0530, Anshuman Khandual wrote:
> +/*
> + * get_arm64_ftr_reg - Looks up a feature register entry using
> + * its sys_reg() encoding. This calls get_arm64_ftr_reg_nowarn().
> + *
> + * returns - Upon success,  matching ftr_reg entry for id.
> + *         - NULL on failure but with an WARN_ON().
> + */
> +static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
> +{
> +	struct arm64_ftr_reg *reg;
> +
> +	reg = get_arm64_ftr_reg_nowarn(sys_id);
> +
> +	/*
> +	 * Can not really proceed when the search fails here.
> +	 * Requesting for a non existent register search will
> +	 * be an error. Warn but let it continue for now.
> +	 */
> +	WARN_ON(!reg);
> +	return reg;

I find the comment here slightly confusing: cannot proceed but continue.
Maybe something like:

	/*
	 * Requesting a non-existent register search is an error. Warn
	 * and let the caller handle it.
	 */

Otherwise it looks fine:

Reviewed-by: Catalin Marinas <catalin.marinas@....com>