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" <paul...@kernel.org>
Signed-off-by: Qais Yousef <qais.you...@arm.com>
CC: Thomas Gleixner <t...@linutronix.de>
CC: "Paul E. McKenney" <paul...@kernel.org>
CC: Helge Deller <del...@gmx.de>
CC: Michael Ellerman <m...@ellerman.id.au>
CC: "David S. Miller" <da...@davemloft.net>
CC: Juergen Gross <jgr...@suse.com>
CC: Mark Rutland <mark.rutl...@arm.com>
CC: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
CC: xen-devel@lists.xenproject.org
CC: linux-par...@vger.kernel.org
CC: sparcli...@vger.kernel.org
CC: linuxppc-...@lists.ozlabs.org
CC: linux-arm-ker...@lists.infradead.org
CC: x...@kernel.org
CC: linux-ker...@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
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
