linux-kernel - Re: [Regression, post-2.6.34-rc1][PATCH] x86 / perf: Fix suspend to RAM on HP nx6325

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Message-ID: <alpine.LFD.2.00.1003211029480.18017@i5.linux-foundation.org>
Date:	Sun, 21 Mar 2010 10:31:52 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
cc:	Peter Zijlstra <peterz@...radead.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [Regression, post-2.6.34-rc1][PATCH] x86 / perf: Fix suspend to
 RAM on HP nx6325



On Sat, 20 Mar 2010, Rafael J. Wysocki wrote:
>
> The appended patch fixes the breakage for me too.

Please don't use a 'goto' for something like this.

>  	raw_spin_lock(&amd_nb_lock);
>  
> +	if (!cpuhw->amd_nb)
> +		goto unlock;
> +
>  	if (--cpuhw->amd_nb->refcnt == 0)
>  		kfree(cpuhw->amd_nb);
>  
>  	cpuhw->amd_nb = NULL;
>  
> + unlock:
>  	raw_spin_unlock(&amd_nb_lock);
>  }

Just do

	raw_spin_lock(&amd_nb_lock);
	if (cpuhw->amd_nb) {
		if (!--cpuhw->amd_nb->refcnt)
			kfree(cpuhw->amd_nb);
		cpuhw->amd_nb = NULL;
	}
	raw_spin_unlock(&amd_nb_lock);

instead. Much more readable.

Let's keep 'goto' for cases where we have error returns that we don't want 
to nest, not trivial stuff like this.

		Linus
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