linux-kernel - Re: [PATCH v9 8/10] x86, mm: Add set_memory

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Date:	Fri, 22 May 2015 09:48:41 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Toshi Kani <toshi.kani@...com>
cc:	hpa@...or.com, mingo@...hat.com, akpm@...ux-foundation.org,
	arnd@...db.de, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	x86@...nel.org, linux-nvdimm@...1.01.org, jgross@...e.com,
	stefan.bader@...onical.com, luto@...capital.net, hmh@....eng.br,
	yigal@...xistor.com, konrad.wilk@...cle.com, Elliott@...com,
	mcgrof@...e.com, hch@....de
Subject: Re: [PATCH v9 8/10] x86, mm: Add set_memory_wt() for WT

On Wed, 13 May 2015, Toshi Kani wrote:
> +int set_memory_wt(unsigned long addr, int numpages)
> +{
> +	int ret;
> +
> +	if (!pat_enabled)
> +		return set_memory_uc(addr, numpages);
> +
> +	ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
> +			      _PAGE_CACHE_MODE_WT, NULL);
> +	if (ret)
> +		goto out_err;
> +
> +	ret = _set_memory_wt(addr, numpages);
> +	if (ret)
> +		goto out_free;
> +
> +	return 0;
> +
> +out_free:
> +	free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
> +out_err:
> +	return ret;


This goto zoo is horrible to read. What's wrong with a straight forward:

+	if (!pat_enabled)
+		return set_memory_uc(addr, numpages);
+
+	ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
+			      _PAGE_CACHE_MODE_WT, NULL);
+	if (ret)
+		return ret;
+
+	ret = _set_memory_wt(addr, numpages);
+	if (ret)
+		free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
+	return ret;

Thanks,

	tglx
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