Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754489AbbBJVtf (ORCPT ); Tue, 10 Feb 2015 16:49:35 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:46571 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751599AbbBJVte (ORCPT ); Tue, 10 Feb 2015 16:49:34 -0500 Message-ID: <54DA7CEC.7020606@codeaurora.org> Date: Tue, 10 Feb 2015 13:49:32 -0800 From: Stephen Boyd User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Russell King - ARM Linux CC: Mark Rutland , "Paul E. McKenney" , Krzysztof Kozlowski , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann , Bartlomiej Zolnierkiewicz , Marek Szyprowski , Catalin Marinas , Will Deacon Subject: Re: [PATCH v2] ARM: Don't use complete() during __cpu_die References: <1423131270-24047-1-git-send-email-k.kozlowski@samsung.com> <20150205105035.GL8656@n2100.arm.linux.org.uk> <20150205142918.GA10634@linux.vnet.ibm.com> <20150205161100.GQ8656@n2100.arm.linux.org.uk> <54D95DB8.9010308@codeaurora.org> <20150210151416.GD9432@leverpostej> <54DA6E92.3090109@codeaurora.org> <54DA725E.6080305@codeaurora.org> <20150210211525.GO8656@n2100.arm.linux.org.uk> In-Reply-To: <20150210211525.GO8656@n2100.arm.linux.org.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3458 Lines: 100 On 02/10/15 13:15, Russell King - ARM Linux wrote: > On Tue, Feb 10, 2015 at 01:04:30PM -0800, Stephen Boyd wrote: >> From: Stephen Boyd >> Subject: [PATCH] ARM: smp: Only expose /sys/.../cpuX/online if hotpluggable >> >> Writes to /sys/.../cpuX/online fail if we determine the platform >> doesn't support hotplug for that CPU. Let's figure this out >> befoer we make the sysfs nodes so that the online file doesn't >> even exist if it's not possible to hotplug the CPU. >> >> Signed-off-by: Stephen Boyd >> --- >> arch/arm/include/asm/smp.h | 6 ++++++ >> arch/arm/kernel/setup.c | 2 +- >> arch/arm/kernel/smp.c | 11 ++++------- >> 3 files changed, 11 insertions(+), 8 deletions(-) >> >> diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h >> index 18f5a554134f..9f82430efd59 100644 >> --- a/arch/arm/include/asm/smp.h >> +++ b/arch/arm/include/asm/smp.h >> @@ -123,4 +123,10 @@ struct of_cpu_method { >> */ >> extern void smp_set_ops(struct smp_operations *); >> >> +#ifdef CONFIG_HOTPLUG_CPU >> +extern int platform_can_hotplug_cpu(unsigned int cpu); >> +#else >> +static inline int platform_can_hotplug_cpu(unsigned int cpu) { return 0; } > Please split this across four lines like a normal function. > Ok. >> +#endif >> + >> #endif /* ifndef __ASM_ARM_SMP_H */ >> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c >> index 715ae19bc7c8..c61c09defc78 100644 >> --- a/arch/arm/kernel/setup.c >> +++ b/arch/arm/kernel/setup.c >> @@ -974,7 +974,7 @@ static int __init topology_init(void) >> >> for_each_possible_cpu(cpu) { >> struct cpuinfo_arm *cpuinfo = &per_cpu(cpu_data, cpu); >> - cpuinfo->cpu.hotpluggable = 1; >> + cpuinfo->cpu.hotpluggable = platform_can_hotplug_cpu(cpu); >> register_cpu(&cpuinfo->cpu, cpu); >> } >> >> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c >> index fe0386c751b2..4d213b24db60 100644 >> --- a/arch/arm/kernel/smp.c >> +++ b/arch/arm/kernel/smp.c >> @@ -174,18 +174,19 @@ static int platform_cpu_kill(unsigned int cpu) >> return 1; >> } >> >> -static int platform_cpu_disable(unsigned int cpu) >> +int platform_can_hotplug_cpu(unsigned int cpu) >> { >> if (smp_ops.cpu_disable) >> - return smp_ops.cpu_disable(cpu); >> + return smp_ops.cpu_disable(cpu) ? 0 : 1; >> >> /* >> * By default, allow disabling all CPUs except the first one, >> * since this is special on a lot of platforms, e.g. because >> * of clock tick interrupts. >> */ >> - return cpu == 0 ? -EPERM : 0; >> + return cpu == 0 ? 0 : 1; >> } >> + >> /* >> * __cpu_disable runs on the processor to be shutdown. >> */ >> @@ -194,10 +195,6 @@ int __cpu_disable(void) >> unsigned int cpu = smp_processor_id(); >> int ret; >> >> - ret = platform_cpu_disable(cpu); >> - if (ret) >> - return ret; >> - > I would much rather prefer smp_ops.cpu_disable() to be renamed in this > case - name it smp_ops.cpu_can_disable() so that it's clear that it's > no longer part of the __cpu_disable() path. Sure. That also makes the ? 0 : 1 thing go away. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/