Re: [PATCH v5 07/12] x86/apic: Unify interrupt mode setup for UP system

From: Thomas Gleixner <tglx@linutronix.de>
To: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	xen-devel@lists.xenproject.org, mingo@kernel.org, hpa@zytor.com,
	ebiederm@xmission.com, bhe@redhat.com,
	boris.ostrovsky@oracle.com, peterz@infradead.org,
	izumi.taku@jp.fujitsu.com
Subject: Re: [PATCH v5 07/12] x86/apic: Unify interrupt mode setup for UP system
Date: Sun, 2 Jul 2017 20:19:54 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1707022011040.2296@nanos> (raw)
In-Reply-To: <1fa26228fa94779d12d4089b83a43fe157b110fe.1498795030.git.douly.fnst@cn.fujitsu.com>

On Fri, 30 Jun 2017, Dou Liyang wrote:
>  static inline int apic_force_enable(unsigned long addr)
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index 0601054..9bf7e95 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -1198,6 +1198,10 @@ static int __init apic_intr_mode_select(int *upmode)
>  	}
>  #endif
>  
> +#ifdef CONFIG_UP_LATE_INIT
> +	*upmode = true;
> +#endif

This is really wrong. The upmode decision, which is required for calling
apic_bsp_setup() should not happen here, really. As I told you in the
previous patch, use the return code and then you can make further decisions
in apic_intr_mode_init().

And you do it there w/o any ifdeffery:

static void apic_intr_mode_init(void)
{
	bool upmode = IS_ENABLED(CONFIG_UP_LATE_INIT);

	switch (....) {
	case XXXX:
		upmode = true;
		....
	}
	apic_bsp_setup(upmode);
}

Thanks,

	tglx