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Message-ID: <49A524D3.3090408@gmail.com>
Date: Wed, 25 Feb 2009 12:00:35 +0100
From: Jiri Slaby <jirislaby@gmail.com>
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To: mingo@redhat.com
CC: x86@kernel.org, linux-kernel@vger.kernel.org,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v2 1/2] x86_32: summit_32, use BAD_APICID
References: <20090224175518.GA15616@elte.hu> <1235508093-18063-1-git-send-email-jirislaby@gmail.com>
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On 24.2.2009 21:41, Jiri Slaby wrote:
> --- a/arch/x86/kernel/apic/summit_32.c
> +++ b/arch/x86/kernel/apic/summit_32.c
> @@ -303,12 +303,10 @@ static inline unsigned int summit_cpu_mask_to_apicid(const cpumask_t *cpumask)
>   	int cpu;
>
>   	num_bits_set = cpus_weight(*cpumask);
> -	/* Return id to all */
>   	if (num_bits_set>= nr_cpu_ids)
> -		return 0xFF;
> +		return BAD_APICID;

Actually, wasn't this intended to return all available rather than BAD 
(to which would correspond the comment), but performed in a wrong 
manner? This is old code, any ideas who would know this?

In my opinion the check should be removed completely to allow the code 
go through same-cluster check.

In that case, the callers code is buggy, since it passes online_cpu 
masks even on machines, where apics are not on the same clusters.