linux-kernel - Re: [Patch v3 02/13] x86/speculation: Remove unnecessary ret variable in cpu_show

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Date:   Thu, 18 Oct 2018 14:46:52 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Tim Chen <tim.c.chen@...ux.intel.com>
cc:     Jiri Kosina <jikos@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Casey Schaufler <casey.schaufler@...el.com>,
        Asit Mallick <asit.k.mallick@...el.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Jon Masters <jcm@...hat.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org
Subject: Re: [Patch v3 02/13] x86/speculation: Remove unnecessary ret variable
 in cpu_show_common

On Wed, 17 Oct 2018, Tim Chen wrote:

> Remove unecessary ret variable in cpu_show_common.
>
> Break up long lines too to make the code more concise
> and easier to read and modify in later patches.

So this does two things at once.

>  static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
>  			       char *buf, unsigned int bug)
>  {
> -	int ret;
> -
>  	if (!boot_cpu_has_bug(bug))
>  		return sprintf(buf, "Not affected\n");
>  
> @@ -873,13 +871,17 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
>  		return sprintf(buf, "Mitigation: __user pointer sanitization\n");
>  
>  	case X86_BUG_SPECTRE_V2:
> -		ret = sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
> -			       boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "",
> -			       boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
> -			       (x86_spec_ctrl_base & SPEC_CTRL_STIBP) ? ", STIBP" : "",
> -			       boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
> -			       spectre_v2_module_string());
> -		return ret;
> +		return sprintf(buf, "%s%s%s%s%s%s\n",
> +			spectre_v2_strings[spectre_v2_enabled],
> +			boot_cpu_has(X86_FEATURE_USE_IBPB) ?
> +				   ", IBPB" : "",
> +			boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ?
> +				   ", IBRS_FW" : "",
> +			(x86_spec_ctrl_base & SPEC_CTRL_STIBP) ?
> +				   ", STIBP" : "",
> +			boot_cpu_has(X86_FEATURE_RSB_CTXSW) ?
> +				   ", RSB filling" : "",

And I do not agree at all that this is more readable.

IMO it's actually worse and I do not see how that makes it easier to
modify.

Thanks,

	tglx