From patchwork Sat Aug 17 19:46:59 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Toshi Kani X-Patchwork-Id: 267998 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 431E62C01C2 for ; Sun, 18 Aug 2013 05:56:09 +1000 (EST) Received: from g6t0187.atlanta.hp.com (g6t0187.atlanta.hp.com [15.193.32.64]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "smtp.hp.com", Issuer "VeriSign Class 3 Secure Server CA - G3" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 799062C0200 for ; Sun, 18 Aug 2013 05:55:08 +1000 (EST) Received: from g5t0029.atlanta.hp.com (g5t0029.atlanta.hp.com [16.228.8.141]) by g6t0187.atlanta.hp.com (Postfix) with ESMTP id 27DE328103; Sat, 17 Aug 2013 19:49:01 +0000 (UTC) Received: from misato.fc.hp.com (swa01lbdc1025-026-vl250-snat3.atlanta.hp.com [16.228.13.93]) by g5t0029.atlanta.hp.com (Postfix) with ESMTP id 4B2E2200AF; Sat, 17 Aug 2013 19:49:00 +0000 (UTC) From: Toshi Kani To: mingo@redhat.com, hpa@linux.intel.com, tglx@linutronix.de, gregkh@linuxfoundation.org, benh@kernel.crashing.org Subject: [PATCH 4/4] hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() Date: Sat, 17 Aug 2013 13:46:59 -0600 Message-Id: <1376768819-28975-5-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1376768819-28975-1-git-send-email-toshi.kani@hp.com> References: <1376768819-28975-1-git-send-email-toshi.kani@hp.com> Cc: fenghua.yu@intel.com, Toshi Kani , x86@kernel.org, linux-kernel@vger.kernel.org, rjw@sisk.pl, isimatu.yasuaki@jp.fujitsu.com, srivatsa.bhat@linux.vnet.ibm.com, bp@suse.de, linuxppc-dev@lists.ozlabs.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 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)