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Commit fa2be40f authored by Seth Jennings's avatar Seth Jennings Committed by Greg Kroah-Hartman
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drivers: base: use standard device online/offline for state change 



There are two ways to set the online/offline state for a memory block:
echo 0|1 > online and echo online|online_kernel|online_movable|offline >
state.

The state attribute can online a memory block with extra data, the
"online type", where the online attribute uses a default online type of
ONLINE_KEEP, same as echo online > state.

Currently there is a state_mutex that provides consistency between the
memory block state and the underlying memory.

The problem is that this code does a lot of things that the common
device layer can do for us, such as the serialization of the
online/offline handlers using the device lock, setting the dev->offline
field, and calling kobject_uevent().

This patch refactors the online/offline code to allow the common
device_[online|offline] functions to be used.  The result is a simpler
and more common code path for the two state setting mechanisms.  It also
removes the state_mutex from the struct memory_block as the memory block
device lock provides the state consistency.

No functional change is intended by this patch.

Signed-off-by: default avatarSeth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cb5e39b8

drivers/base/memory.c

+55 −72
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ 
#include <linux/capability.h>

#include <linux/device.h>

#include <linux/memory.h>

#include <linux/kobject.h>

#include <linux/memory_hotplug.h>

#include <linux/mm.h>

#include <linux/mutex.h>
@@ -261,9 +260,8 @@ memory_block_action(unsigned long phys_index, unsigned long action, int online_t 
	return ret;

}



static int __memory_block_change_state(struct memory_block *mem,

		unsigned long to_state, unsigned long from_state_req,

		int online_type)

static int memory_block_change_state(struct memory_block *mem,

		unsigned long to_state, unsigned long from_state_req)

{

	int ret = 0;
@@ -273,105 +271,91 @@ static int __memory_block_change_state(struct memory_block *mem, 
	if (to_state == MEM_OFFLINE)

		mem->state = MEM_GOING_OFFLINE;



	ret = memory_block_action(mem->start_section_nr, to_state, online_type);

	ret = memory_block_action(mem->start_section_nr, to_state,

				mem->online_type);



	mem->state = ret ? from_state_req : to_state;



	return ret;

}



/* The device lock serializes operations on memory_subsys_[online|offline] */

static int memory_subsys_online(struct device *dev)

{

	struct memory_block *mem = container_of(dev, struct memory_block, dev);

	int ret;



	mutex_lock(&mem->state_mutex);

	if (mem->state == MEM_ONLINE)

		return 0;



	ret = mem->state == MEM_ONLINE ? 0 :

		__memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE,

					    ONLINE_KEEP);

	/*

	 * If we are called from store_mem_state(), online_type will be

	 * set >= 0 Otherwise we were called from the device online

	 * attribute and need to set the online_type.

	 */

	if (mem->online_type < 0)

		mem->online_type = ONLINE_KEEP;



	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);



	/* clear online_type */

	mem->online_type = -1;



	mutex_unlock(&mem->state_mutex);

	return ret;

}



static int memory_subsys_offline(struct device *dev)

{

	struct memory_block *mem = container_of(dev, struct memory_block, dev);

	int ret;



	mutex_lock(&mem->state_mutex);



	ret = mem->state == MEM_OFFLINE ? 0 :

		__memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);

	if (mem->state == MEM_OFFLINE)

		return 0;



	mutex_unlock(&mem->state_mutex);

	return ret;

	return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);

}



static int __memory_block_change_state_uevent(struct memory_block *mem,

		unsigned long to_state, unsigned long from_state_req,

		int online_type)

{

	int ret = __memory_block_change_state(mem, to_state, from_state_req,

					      online_type);

	if (!ret) {

		switch (mem->state) {

		case MEM_OFFLINE:

			kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);

			break;

		case MEM_ONLINE:

			kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);

			break;

		default:

			break;

		}

	}

	return ret;

}



static int memory_block_change_state(struct memory_block *mem,

		unsigned long to_state, unsigned long from_state_req,

		int online_type)

{

	int ret;



	mutex_lock(&mem->state_mutex);

	ret = __memory_block_change_state_uevent(mem, to_state, from_state_req,

						 online_type);

	mutex_unlock(&mem->state_mutex);



	return ret;

}

static ssize_t

store_mem_state(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t count)

{

	struct memory_block *mem;

	bool offline;

	int ret = -EINVAL;

	int ret, online_type;



	mem = container_of(dev, struct memory_block, dev);



	lock_device_hotplug();



	if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) {

		offline = false;

		ret = memory_block_change_state(mem, MEM_ONLINE,

						MEM_OFFLINE, ONLINE_KERNEL);

	} else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) {

		offline = false;

		ret = memory_block_change_state(mem, MEM_ONLINE,

						MEM_OFFLINE, ONLINE_MOVABLE);

	} else if (!strncmp(buf, "online", min_t(int, count, 6))) {

		offline = false;

		ret = memory_block_change_state(mem, MEM_ONLINE,

						MEM_OFFLINE, ONLINE_KEEP);

	} else if(!strncmp(buf, "offline", min_t(int, count, 7))) {

		offline = true;

		ret = memory_block_change_state(mem, MEM_OFFLINE,

						MEM_ONLINE, -1);

	if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))

		online_type = ONLINE_KERNEL;

	else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))

		online_type = ONLINE_MOVABLE;

	else if (!strncmp(buf, "online", min_t(int, count, 6)))

		online_type = ONLINE_KEEP;

	else if (!strncmp(buf, "offline", min_t(int, count, 7)))

		online_type = -1;

	else

		return -EINVAL;



	switch (online_type) {

	case ONLINE_KERNEL:

	case ONLINE_MOVABLE:

	case ONLINE_KEEP:

		/*

		 * mem->online_type is not protected so there can be a

		 * race here.  However, when racing online, the first

		 * will succeed and the second will just return as the

		 * block will already be online.  The online type

		 * could be either one, but that is expected.

		 */

		mem->online_type = online_type;

		ret = device_online(&mem->dev);

		break;

	case -1:

		ret = device_offline(&mem->dev);

		break;

	default:

		ret = -EINVAL; /* should never happen */

	}

	if (!ret)

		dev->offline = offline;



	unlock_device_hotplug();
@@ -592,7 +576,6 @@ static int init_memory_block(struct memory_block **memory, 
	mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;

	mem->state = state;

	mem->section_count++;

	mutex_init(&mem->state_mutex);

	start_pfn = section_nr_to_pfn(mem->start_section_nr);

	mem->phys_device = arch_get_memory_phys_device(start_pfn);

include/linux/memory.h

+3 −10
Original line number Diff line number Diff line
@@ -25,16 +25,9 @@ 
struct memory_block {

	unsigned long start_section_nr;

	unsigned long end_section_nr;

	unsigned long state;

	int section_count;



	/*

	 * This serializes all state change requests.  It isn't

	 * held during creation because the control files are

	 * created long after the critical areas during

	 * initialization.

	 */

	struct mutex state_mutex;

	unsigned long state;		/* serialized by the dev->lock */

	int section_count;		/* serialized by mem_sysfs_mutex */

	int online_type;		/* for passing data to online routine */

	int phys_device;		/* to which fru does this belong? */

	void *hw;			/* optional pointer to fw/hw data */

	int (*phys_callback)(struct memory_block *);