Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753699Ab3HRAvM (ORCPT ); Sat, 17 Aug 2013 20:51:12 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:47383 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752364Ab3HRAvL (ORCPT ); Sat, 17 Aug 2013 20:51:11 -0400 From: "Rafael J. Wysocki" To: Toshi Kani Cc: mingo@redhat.com, hpa@linux.intel.com, tglx@linutronix.de, gregkh@linuxfoundation.org, benh@kernel.crashing.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, fenghua.yu@intel.com, bp@suse.de, srivatsa.bhat@linux.vnet.ibm.com, isimatu.yasuaki@jp.fujitsu.com Subject: Re: [PATCH 4/4] hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() Date: Sun, 18 Aug 2013 03:01:42 +0200 Message-ID: <3579218.MGhjC2kLWm@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.11.0-rc5+; KDE/4.9.5; x86_64; ; ) In-Reply-To: <1376768819-28975-5-git-send-email-toshi.kani@hp.com> References: <1376768819-28975-1-git-send-email-toshi.kani@hp.com> <1376768819-28975-5-git-send-email-toshi.kani@hp.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6919 Lines: 245 On Saturday, August 17, 2013 01:46:59 PM Toshi Kani wrote: > cpu_hotplug_driver_lock() serializes CPU online/offline operations > when ARCH_CPU_PROBE_RELEASE is set. This lock interface is no longer > necessary with the following reason: > > - lock_device_hotplug() now protects CPU online/offline operations, > including the probe & release interfaces enabled by > ARCH_CPU_PROBE_RELEASE. The use of cpu_hotplug_driver_lock() is > redundant. > - cpu_hotplug_driver_lock() is only valid when ARCH_CPU_PROBE_RELEASE > is defined, which is misleading and is only enabled on powerpc. > > This patch removes the cpu_hotplug_driver_lock() interface. As > a result, ARCH_CPU_PROBE_RELEASE only enables / disables the cpu > probe & release interface as intended. There is no functional change > in this patch. > > Signed-off-by: Toshi Kani Acked-by: Rafael J. Wysocki > --- > Performed build test only on powerpc. > --- > arch/powerpc/kernel/smp.c | 12 ---------- > arch/powerpc/platforms/pseries/dlpar.c | 40 ++++++++++++-------------------- > arch/x86/kernel/topology.c | 2 -- > drivers/base/cpu.c | 10 +------- > include/linux/cpu.h | 13 ---------- > 5 files changed, 16 insertions(+), 61 deletions(-) > > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c > index 38b0ba6..1667269 100644 > --- a/arch/powerpc/kernel/smp.c > +++ b/arch/powerpc/kernel/smp.c > @@ -763,18 +763,6 @@ void __cpu_die(unsigned int cpu) > smp_ops->cpu_die(cpu); > } > > -static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex); > - > -void cpu_hotplug_driver_lock() > -{ > - mutex_lock(&powerpc_cpu_hotplug_driver_mutex); > -} > - > -void cpu_hotplug_driver_unlock() > -{ > - mutex_unlock(&powerpc_cpu_hotplug_driver_mutex); > -} > - > void cpu_die(void) > { > if (ppc_md.cpu_die) > diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c > index a1a7b9a..e39325d 100644 > --- a/arch/powerpc/platforms/pseries/dlpar.c > +++ b/arch/powerpc/platforms/pseries/dlpar.c > @@ -387,18 +387,13 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count) > char *cpu_name; > int rc; > > - cpu_hotplug_driver_lock(); > rc = strict_strtoul(buf, 0, &drc_index); > - if (rc) { > - rc = -EINVAL; > - goto out; > - } > + if (rc) > + return -EINVAL; > > dn = dlpar_configure_connector(drc_index); > - if (!dn) { > - rc = -EINVAL; > - goto out; > - } > + if (!dn) > + return -EINVAL; > > /* configure-connector reports cpus as living in the base > * directory of the device tree. CPUs actually live in the > @@ -407,8 +402,7 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count) > cpu_name = kasprintf(GFP_KERNEL, "/cpus%s", dn->full_name); > if (!cpu_name) { > dlpar_free_cc_nodes(dn); > - rc = -ENOMEM; > - goto out; > + return -ENOMEM; > } > > kfree(dn->full_name); > @@ -417,22 +411,21 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count) > rc = dlpar_acquire_drc(drc_index); > if (rc) { > dlpar_free_cc_nodes(dn); > - rc = -EINVAL; > - goto out; > + return -EINVAL; > } > > rc = dlpar_attach_node(dn); > if (rc) { > dlpar_release_drc(drc_index); > dlpar_free_cc_nodes(dn); > - goto out; > + return rc; > } > > rc = dlpar_online_cpu(dn); > -out: > - cpu_hotplug_driver_unlock(); > + if (rc) > + return rc; > > - return rc ? rc : count; > + return count; > } > > static int dlpar_offline_cpu(struct device_node *dn) > @@ -505,30 +498,27 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count) > return -EINVAL; > } > > - cpu_hotplug_driver_lock(); > rc = dlpar_offline_cpu(dn); > if (rc) { > of_node_put(dn); > - rc = -EINVAL; > - goto out; > + return -EINVAL; > } > > rc = dlpar_release_drc(*drc_index); > if (rc) { > of_node_put(dn); > - goto out; > + return rc; > } > > rc = dlpar_detach_node(dn); > if (rc) { > dlpar_acquire_drc(*drc_index); > - goto out; > + return rc; > } > > of_node_put(dn); > -out: > - cpu_hotplug_driver_unlock(); > - return rc ? rc : count; > + > + return count; > } > > static int __init pseries_dlpar_init(void) > diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c > index a3f35eb..649b010 100644 > --- a/arch/x86/kernel/topology.c > +++ b/arch/x86/kernel/topology.c > @@ -66,7 +66,6 @@ int __ref _debug_hotplug_cpu(int cpu, int action) > return -EINVAL; > > lock_device_hotplug(); > - cpu_hotplug_driver_lock(); > > switch (action) { > case 0: > @@ -91,7 +90,6 @@ int __ref _debug_hotplug_cpu(int cpu, int action) > ret = -EINVAL; > } > > - cpu_hotplug_driver_unlock(); > unlock_device_hotplug(); > > return ret; > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > index 4cc6928..b4ebd7b 100644 > --- a/drivers/base/cpu.c > +++ b/drivers/base/cpu.c > @@ -45,8 +45,6 @@ static int __ref cpu_subsys_online(struct device *dev) > int from_nid, to_nid; > int ret; > > - cpu_hotplug_driver_lock(); > - > from_nid = cpu_to_node(cpuid); > ret = cpu_up(cpuid); > /* > @@ -57,18 +55,12 @@ static int __ref cpu_subsys_online(struct device *dev) > if (from_nid != to_nid) > change_cpu_under_node(cpu, from_nid, to_nid); > > - cpu_hotplug_driver_unlock(); > return ret; > } > > static int cpu_subsys_offline(struct device *dev) > { > - int ret; > - > - cpu_hotplug_driver_lock(); > - ret = cpu_down(dev->id); > - cpu_hotplug_driver_unlock(); > - return ret; > + return cpu_down(dev->id); > } > > void unregister_cpu(struct cpu *cpu) > diff --git a/include/linux/cpu.h b/include/linux/cpu.h > index ab0eade..e847ef8 100644 > --- a/include/linux/cpu.h > +++ b/include/linux/cpu.h > @@ -182,19 +182,6 @@ extern void cpu_hotplug_enable(void); > void clear_tasks_mm_cpumask(int cpu); > int cpu_down(unsigned int cpu); > > -#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE > -extern void cpu_hotplug_driver_lock(void); > -extern void cpu_hotplug_driver_unlock(void); > -#else > -static inline void cpu_hotplug_driver_lock(void) > -{ > -} > - > -static inline void cpu_hotplug_driver_unlock(void) > -{ > -} > -#endif > - > #else /* CONFIG_HOTPLUG_CPU */ > > #define get_online_cpus() do { } while (0) > -- > 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/ -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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/