From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Date: Fri, 13 Feb 2015 20:23:22 +0000 Subject: Re: [PATCH v2] ARM: smp: Only expose /sys/.../cpuX/online if hotpluggable Message-Id: <54DE5D3A.5070104@codeaurora.org> List-Id: References: <1423850799-4028-1-git-send-email-sboyd@codeaurora.org> <20150213202002.GB29727@verge.net.au> In-Reply-To: <20150213202002.GB29727@verge.net.au> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On 02/13/15 12:20, Simon Horman wrote: > Hi Stephen, > > On Fri, Feb 13, 2015 at 10:06:39AM -0800, Stephen Boyd wrote: >> diff --git a/arch/arm/mach-shmobile/smp-r8a7779.c b/arch/arm/mach-shmobile/smp-r8a7779.c >> index 3f761f839043..b45206f93ddf 100644 >> --- a/arch/arm/mach-shmobile/smp-r8a7779.c >> +++ b/arch/arm/mach-shmobile/smp-r8a7779.c >> @@ -124,19 +124,12 @@ static int r8a7779_cpu_kill(unsigned int cpu) >> >> return 0; >> } >> - >> -static int r8a7779_cpu_disable(unsigned int cpu) >> -{ >> - /* only CPU1->3 have power domains, do not allow hotplug of CPU0 */ >> - return cpu = 0 ? -EPERM : 0; >> -} >> #endif /* CONFIG_HOTPLUG_CPU */ >> >> struct smp_operations r8a7779_smp_ops __initdata = { >> .smp_prepare_cpus = r8a7779_smp_prepare_cpus, >> .smp_boot_secondary = r8a7779_boot_secondary, >> #ifdef CONFIG_HOTPLUG_CPU >> - .cpu_disable = r8a7779_cpu_disable, >> .cpu_die = shmobile_smp_scu_cpu_die, >> .cpu_kill = r8a7779_cpu_kill, >> #endif > Its not clear to me why r8a7779_cpu_disable() has been > removed rather than replaced by r8a7779_cpu_can_disable() By default ARM's smp.c assumes that CPU0 can't be hotplugged. The function is redundant. I guess I should have mentioned that in the commit text. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project