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Commit 6dedcca6 authored by Toshi Kani's avatar Toshi Kani Committed by Rafael J. Wysocki
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hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() 



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: default avatarToshi Kani <toshi.kani@hp.com>
Reviewed-by: default avatarNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 1cad5e9a

arch/powerpc/kernel/smp.c

+0 −12
Original line number Diff line number Diff line
@@ -844,18 +844,6 @@ 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)

arch/powerpc/platforms/pseries/dlpar.c

+16 −27
Original line number Diff line number Diff line
@@ -404,46 +404,38 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count) 
	unsigned long drc_index;

	int rc;



	cpu_hotplug_driver_lock();

	rc = strict_strtoul(buf, 0, &drc_index);

	if (rc) {

		rc = -EINVAL;

		goto out;

	}

	if (rc)

		return -EINVAL;



	parent = of_find_node_by_path("/cpus");

	if (!parent) {

		rc = -ENODEV;

		goto out;

	}

	if (!parent)

		return -ENODEV;



	dn = dlpar_configure_connector(drc_index, parent);

	if (!dn) {

		rc = -EINVAL;

		goto out;

	}

	if (!dn)

		return -EINVAL;



	of_node_put(parent);



	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)
@@ -516,30 +508,27 @@ 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)

arch/x86/kernel/topology.c

+0 −2
Original line number Diff line number Diff line
@@ -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;

drivers/base/cpu.c

+3 −12
Original line number Diff line number Diff line
@@ -44,13 +44,11 @@ static int __ref cpu_subsys_online(struct device *dev) 
	struct cpu *cpu = container_of(dev, struct cpu, dev);

	int cpuid = dev->id;

	int from_nid, to_nid;

	int ret = -ENODEV;



	cpu_hotplug_driver_lock();

	int ret;



	from_nid = cpu_to_node(cpuid);

	if (from_nid == NUMA_NO_NODE)

		goto out;

		return -ENODEV;



	ret = cpu_up(cpuid);

	/*
@@ -61,19 +59,12 @@ static int __ref cpu_subsys_online(struct device *dev) 
	if (from_nid != to_nid)

		change_cpu_under_node(cpu, from_nid, to_nid);



 out:

	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)

include/linux/cpu.h

+0 −13
Original line number Diff line number Diff line
@@ -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) {}