From: Qais Yousef <qais.yousef@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>,
Mark Rutland <mark.rutland@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
linux-parisc@vger.kernel.org,
"Paul E . McKenney" <paulmck@kernel.org>,
Helge Deller <deller@gmx.de>,
x86@kernel.org, linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org,
linuxppc-dev@lists.ozlabs.org, Qais Yousef <qais.yousef@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 01/15] cpu: Add new {add,remove}_cpu() functions
Date: Sun, 23 Feb 2020 19:29:28 +0000 [thread overview]
Message-ID: <20200223192942.18420-2-qais.yousef@arm.com> (raw)
In-Reply-To: <20200223192942.18420-1-qais.yousef@arm.com>
The new functions use device_{online,offline}() which are userspace
safe.
This is in preparation to move cpu_{up, down} kernel users to use
a safer interface that is not racy with userspace.
Suggested-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: "Paul E. McKenney" <paulmck@kernel.org>
CC: Helge Deller <deller@gmx.de>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Juergen Gross <jgross@suse.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: xen-devel@lists.xenproject.org
CC: linux-parisc@vger.kernel.org
CC: sparclinux@vger.kernel.org
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-arm-kernel@lists.infradead.org
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
include/linux/cpu.h | 2 ++
kernel/cpu.c | 24 ++++++++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 1ca2baf817ed..cf8cf38dca43 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -89,6 +89,7 @@ extern ssize_t arch_cpu_release(const char *, size_t);
#ifdef CONFIG_SMP
extern bool cpuhp_tasks_frozen;
int cpu_up(unsigned int cpu);
+int add_cpu(unsigned int cpu);
void notify_cpu_starting(unsigned int cpu);
extern void cpu_maps_update_begin(void);
extern void cpu_maps_update_done(void);
@@ -118,6 +119,7 @@ extern void cpu_hotplug_disable(void);
extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);
int cpu_down(unsigned int cpu);
+int remove_cpu(unsigned int cpu);
#else /* CONFIG_HOTPLUG_CPU */
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 9c706af713fb..069802f7010f 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1057,6 +1057,18 @@ int cpu_down(unsigned int cpu)
}
EXPORT_SYMBOL(cpu_down);
+int remove_cpu(unsigned int cpu)
+{
+ int ret;
+
+ lock_device_hotplug();
+ ret = device_offline(get_cpu_device(cpu));
+ unlock_device_hotplug();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(remove_cpu);
+
#else
#define takedown_cpu NULL
#endif /*CONFIG_HOTPLUG_CPU*/
@@ -1209,6 +1221,18 @@ int cpu_up(unsigned int cpu)
}
EXPORT_SYMBOL_GPL(cpu_up);
+int add_cpu(unsigned int cpu)
+{
+ int ret;
+
+ lock_device_hotplug();
+ ret = device_online(get_cpu_device(cpu));
+ unlock_device_hotplug();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(add_cpu);
+
#ifdef CONFIG_PM_SLEEP_SMP
static cpumask_var_t frozen_cpus;
--
2.17.1
next prev parent reply other threads:[~2020-02-23 19:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-23 19:29 [PATCH v3 00/15] Convert cpu_up/down to device_online/offline Qais Yousef
2020-02-23 19:29 ` Qais Yousef [this message]
2020-02-23 19:29 ` [PATCH v3 08/15] powerpc: Replace cpu_up/down with add/remove_cpu Qais Yousef
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