Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756420Ab3H3AX5 (ORCPT ); Thu, 29 Aug 2013 20:23:57 -0400 Received: from g1t0029.austin.hp.com ([15.216.28.36]:33983 "EHLO g1t0029.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751625Ab3H3AXz (ORCPT ); Thu, 29 Aug 2013 20:23:55 -0400 From: Toshi Kani To: rjw@sisk.pl Cc: mingo@redhat.com, hpa@linux.intel.com, tglx@linutronix.de, gregkh@linuxfoundation.org, benh@kernel.crashing.org, linux-acpi@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, nfont@linux.vnet.ibm.com, fenghua.yu@intel.com, bp@suse.de, srivatsa.bhat@linux.vnet.ibm.com, isimatu.yasuaki@jp.fujitsu.com, Toshi Kani Subject: [PATCH v2 4/4] hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() Date: Thu, 29 Aug 2013 18:22:09 -0600 Message-Id: <1377822129-4143-5-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1377822129-4143-1-git-send-email-toshi.kani@hp.com> References: <1377822129-4143-1-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6121 Lines: 235 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 Reviewed-by: Nathan Fontenot --- 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 dc78e45..9745f03 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -46,8 +46,6 @@ 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); /* @@ -58,18 +56,12 @@ 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 801ff9e..3434ef7 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -185,19 +185,6 @@ 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 */ static inline void cpu_hotplug_begin(void) {} -- 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/