[mirror_ubuntu-zesty-kernel.git] / drivers / base / memory.c

/*
 * drivers/base/memory.c - basic Memory class support
 *
 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
 *            Dave Hansen <haveblue@us.ibm.com>
 *
 * This file provides the necessary infrastructure to represent
 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
 * All arch-independent code that assumes MEMORY_HOTPLUG requires
 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
 */

#include <linux/sysdev.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>	/* capable() */
#include <linux/topology.h>
#include <linux/device.h>
#include <linux/memory.h>
#include <linux/kobject.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>

#define MEMORY_CLASS_NAME	"memory"

static struct sysdev_class memory_sysdev_class = {
	set_kset_name(MEMORY_CLASS_NAME),
};
EXPORT_SYMBOL(memory_sysdev_class);

static char *memory_hotplug_name(struct kset *kset, struct kobject *kobj)
{
	return MEMORY_CLASS_NAME;
}

static int memory_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
			int num_envp, char *buffer, int buffer_size)
{
	int retval = 0;

	return retval;
}

static struct kset_hotplug_ops memory_hotplug_ops = {
	.name		= memory_hotplug_name,
	.hotplug	= memory_hotplug,
};

static struct notifier_block *memory_chain;

static int register_memory_notifier(struct notifier_block *nb)
{
        return notifier_chain_register(&memory_chain, nb);
}

static void unregister_memory_notifier(struct notifier_block *nb)
{
        notifier_chain_unregister(&memory_chain, nb);
}

/*
 * register_memory - Setup a sysfs device for a memory block
 */
static int
register_memory(struct memory_block *memory, struct mem_section *section,
		struct node *root)
{
	int error;

	memory->sysdev.cls = &memory_sysdev_class;
	memory->sysdev.id = __section_nr(section);

	error = sysdev_register(&memory->sysdev);

	if (root && !error)
		error = sysfs_create_link(&root->sysdev.kobj,
					  &memory->sysdev.kobj,
					  kobject_name(&memory->sysdev.kobj));

	return error;
}

static void
unregister_memory(struct memory_block *memory, struct mem_section *section,
		struct node *root)
{
	BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
	BUG_ON(memory->sysdev.id != __section_nr(section));

	sysdev_unregister(&memory->sysdev);
	if (root)
		sysfs_remove_link(&root->sysdev.kobj,
				  kobject_name(&memory->sysdev.kobj));
}

/*
 * use this as the physical section index that this memsection
 * uses.
 */

static ssize_t show_mem_phys_index(struct sys_device *dev, char *buf)
{
	struct memory_block *mem =
		container_of(dev, struct memory_block, sysdev);
	return sprintf(buf, "%08lx\n", mem->phys_index);
}

/*
 * online, offline, going offline, etc.
 */
static ssize_t show_mem_state(struct sys_device *dev, char *buf)
{
	struct memory_block *mem =
		container_of(dev, struct memory_block, sysdev);
	ssize_t len = 0;

	/*
	 * We can probably put these states in a nice little array
	 * so that they're not open-coded
	 */
	switch (mem->state) {
		case MEM_ONLINE:
			len = sprintf(buf, "online\n");
			break;
		case MEM_OFFLINE:
			len = sprintf(buf, "offline\n");
			break;
		case MEM_GOING_OFFLINE:
			len = sprintf(buf, "going-offline\n");
			break;
		default:
			len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
					mem->state);
			WARN_ON(1);
			break;
	}

	return len;
}

static inline int memory_notify(unsigned long val, void *v)
{
	return notifier_call_chain(&memory_chain, val, v);
}

/*
 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
 * OK to have direct references to sparsemem variables in here.
 */
static int
memory_block_action(struct memory_block *mem, unsigned long action)
{
	int i;
	unsigned long psection;
	unsigned long start_pfn, start_paddr;
	struct page *first_page;
	int ret;
	int old_state = mem->state;

	psection = mem->phys_index;
	first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);

	/*
	 * The probe routines leave the pages reserved, just
	 * as the bootmem code does.  Make sure they're still
	 * that way.
	 */
	if (action == MEM_ONLINE) {
		for (i = 0; i < PAGES_PER_SECTION; i++) {
			if (PageReserved(first_page+i))
				continue;

			printk(KERN_WARNING "section number %ld page number %d "
				"not reserved, was it already online? \n",
				psection, i);
			return -EBUSY;
		}
	}

	switch (action) {
		case MEM_ONLINE:
			start_pfn = page_to_pfn(first_page);
			ret = online_pages(start_pfn, PAGES_PER_SECTION);
			break;
		case MEM_OFFLINE:
			mem->state = MEM_GOING_OFFLINE;
			memory_notify(MEM_GOING_OFFLINE, NULL);
			start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
			ret = remove_memory(start_paddr,
					    PAGES_PER_SECTION << PAGE_SHIFT);
			if (ret) {
				mem->state = old_state;
				break;
			}
			memory_notify(MEM_MAPPING_INVALID, NULL);
			break;
		default:
			printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
					__FUNCTION__, mem, action, action);
			WARN_ON(1);
			ret = -EINVAL;
	}
	/*
	 * For now, only notify on successful memory operations
	 */
	if (!ret)
		memory_notify(action, NULL);

	return ret;
}

static int memory_block_change_state(struct memory_block *mem,
		unsigned long to_state, unsigned long from_state_req)
{
	int ret = 0;
	down(&mem->state_sem);

	if (mem->state != from_state_req) {
		ret = -EINVAL;
		goto out;
	}

	ret = memory_block_action(mem, to_state);
	if (!ret)
		mem->state = to_state;

out:
	up(&mem->state_sem);
	return ret;
}

static ssize_t
store_mem_state(struct sys_device *dev, const char *buf, size_t count)
{
	struct memory_block *mem;
	unsigned int phys_section_nr;
	int ret = -EINVAL;

	mem = container_of(dev, struct memory_block, sysdev);
	phys_section_nr = mem->phys_index;

	if (!valid_section_nr(phys_section_nr))
		goto out;

	if (!strncmp(buf, "online", min((int)count, 6)))
		ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
	else if(!strncmp(buf, "offline", min((int)count, 7)))
		ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
out:
	if (ret)
		return ret;
	return count;
}

/*
 * phys_device is a bad name for this.  What I really want
 * is a way to differentiate between memory ranges that
 * are part of physical devices that constitute
 * a complete removable unit or fru.
 * i.e. do these ranges belong to the same physical device,
 * s.t. if I offline all of these sections I can then
 * remove the physical device?
 */
static ssize_t show_phys_device(struct sys_device *dev, char *buf)
{
	struct memory_block *mem =
		container_of(dev, struct memory_block, sysdev);
	return sprintf(buf, "%d\n", mem->phys_device);
}

static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);

#define mem_create_simple_file(mem, attr_name)	\
	sysdev_create_file(&mem->sysdev, &attr_##attr_name)
#define mem_remove_simple_file(mem, attr_name)	\
	sysdev_remove_file(&mem->sysdev, &attr_##attr_name)

/*
 * Block size attribute stuff
 */
static ssize_t
print_block_size(struct class *class, char *buf)
{
	return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
}

static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);

static int block_size_init(void)
{
	sysfs_create_file(&memory_sysdev_class.kset.kobj,
		&class_attr_block_size_bytes.attr);
	return 0;
}

/*
 * Some architectures will have custom drivers to do this, and
 * will not need to do it from userspace.  The fake hot-add code
 * as well as ppc64 will do all of their discovery in userspace
 * and will require this interface.
 */
#ifdef CONFIG_ARCH_MEMORY_PROBE
static ssize_t
memory_probe_store(struct class *class, const char __user *buf, size_t count)
{
	u64 phys_addr;
	int ret;

	phys_addr = simple_strtoull(buf, NULL, 0);

	ret = add_memory(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);

	if (ret)
		count = ret;

	return count;
}
static CLASS_ATTR(probe, 0700, NULL, memory_probe_store);

static int memory_probe_init(void)
{
	sysfs_create_file(&memory_sysdev_class.kset.kobj,
		&class_attr_probe.attr);
	return 0;
}
#else
#define memory_probe_init(...)	do {} while (0)
#endif

/*
 * Note that phys_device is optional.  It is here to allow for
 * differentiation between which *physical* devices each
 * section belongs to...
 */

static int add_memory_block(unsigned long node_id, struct mem_section *section,
		     unsigned long state, int phys_device)
{
	struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL);
	int ret = 0;

	if (!mem)
		return -ENOMEM;

	mem->phys_index = __section_nr(section);
	mem->state = state;
	init_MUTEX(&mem->state_sem);
	mem->phys_device = phys_device;

	ret = register_memory(mem, section, NULL);
	if (!ret)
		ret = mem_create_simple_file(mem, phys_index);
	if (!ret)
		ret = mem_create_simple_file(mem, state);
	if (!ret)
		ret = mem_create_simple_file(mem, phys_device);

	return ret;
}

/*
 * For now, we have a linear search to go find the appropriate
 * memory_block corresponding to a particular phys_index. If
 * this gets to be a real problem, we can always use a radix
 * tree or something here.
 *
 * This could be made generic for all sysdev classes.
 */
static struct memory_block *find_memory_block(struct mem_section *section)
{
	struct kobject *kobj;
	struct sys_device *sysdev;
	struct memory_block *mem;
	char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];

	/*
	 * This only works because we know that section == sysdev->id
	 * slightly redundant with sysdev_register()
	 */
	sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));

	kobj = kset_find_obj(&memory_sysdev_class.kset, name);
	if (!kobj)
		return NULL;

	sysdev = container_of(kobj, struct sys_device, kobj);
	mem = container_of(sysdev, struct memory_block, sysdev);

	return mem;
}

int remove_memory_block(unsigned long node_id, struct mem_section *section,
		int phys_device)
{
	struct memory_block *mem;

	mem = find_memory_block(section);
	mem_remove_simple_file(mem, phys_index);
	mem_remove_simple_file(mem, state);
	mem_remove_simple_file(mem, phys_device);
	unregister_memory(mem, section, NULL);

	return 0;
}

/*
 * need an interface for the VM to add new memory regions,
 * but without onlining it.
 */
int register_new_memory(struct mem_section *section)
{
	return add_memory_block(0, section, MEM_OFFLINE, 0);
}

int unregister_memory_section(struct mem_section *section)
{
	if (!valid_section(section))
		return -EINVAL;

	return remove_memory_block(0, section, 0);
}

/*
 * Initialize the sysfs support for memory devices...
 */
int __init memory_dev_init(void)
{
	unsigned int i;
	int ret;

	memory_sysdev_class.kset.hotplug_ops = &memory_hotplug_ops;
	ret = sysdev_class_register(&memory_sysdev_class);

	/*
	 * Create entries for memory sections that were found
	 * during boot and have been initialized
	 */
	for (i = 0; i < NR_MEM_SECTIONS; i++) {
		if (!valid_section_nr(i))
			continue;
		add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0);
	}

	memory_probe_init();
	block_size_init();

	return ret;
}
Commit	Line	Data
3947be19 DH	1	/*
	2	* drivers/base/memory.c - basic Memory class support
	3	*
	4	* Written by Matt Tolentino <matthew.e.tolentino@intel.com>
	5	* Dave Hansen <haveblue@us.ibm.com>
	6	*
	7	* This file provides the necessary infrastructure to represent
	8	* a SPARSEMEM-memory-model system's physical memory in /sysfs.
	9	* All arch-independent code that assumes MEMORY_HOTPLUG requires
	10	* SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
	11	*/
	12
	13	#include <linux/sysdev.h>
	14	#include <linux/module.h>
	15	#include <linux/init.h>
	16	#include <linux/sched.h> /* capable() */
	17	#include <linux/topology.h>
	18	#include <linux/device.h>
	19	#include <linux/memory.h>
	20	#include <linux/kobject.h>
	21	#include <linux/memory_hotplug.h>
	22	#include <linux/mm.h>
	23	#include <asm/atomic.h>
	24	#include <asm/uaccess.h>
	25
	26	#define MEMORY_CLASS_NAME "memory"
	27
	28	static struct sysdev_class memory_sysdev_class = {
	29	set_kset_name(MEMORY_CLASS_NAME),
	30	};
	31	EXPORT_SYMBOL(memory_sysdev_class);
	32
	33	static char memory_hotplug_name(struct kset kset, struct kobject *kobj)
	34	{
	35	return MEMORY_CLASS_NAME;
	36	}
	37
	38	static int memory_hotplug(struct kset kset, struct kobject kobj, char **envp,
	39	int num_envp, char *buffer, int buffer_size)
	40	{
	41	int retval = 0;
	42
	43	return retval;
	44	}
	45
	46	static struct kset_hotplug_ops memory_hotplug_ops = {
	47	.name = memory_hotplug_name,
	48	.hotplug = memory_hotplug,
	49	};
	50
	51	static struct notifier_block *memory_chain;
	52
	53	static int register_memory_notifier(struct notifier_block *nb)
	54	{
	55	return notifier_chain_register(&memory_chain, nb);
	56	}
	57
	58	static void unregister_memory_notifier(struct notifier_block *nb)
	59	{
	60	notifier_chain_unregister(&memory_chain, nb);
	61	}
	62
	63	/*
	64	* register_memory - Setup a sysfs device for a memory block
65	*/
66	static int
67	register_memory(struct memory_block memory, struct mem_section section,
68	struct node *root)
69	{
70	int error;
71
72	memory->sysdev.cls = &memory_sysdev_class;
73	memory->sysdev.id = __section_nr(section);
74
75	error = sysdev_register(&memory->sysdev);
76
77	if (root && !error)
78	error = sysfs_create_link(&root->sysdev.kobj,
79	&memory->sysdev.kobj,
80	kobject_name(&memory->sysdev.kobj));
81
82	return error;
83	}
84
85	static void
86	unregister_memory(struct memory_block memory, struct mem_section section,
87	struct node *root)
88	{
89	BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
90	BUG_ON(memory->sysdev.id != __section_nr(section));
91
92	sysdev_unregister(&memory->sysdev);
93	if (root)
94	sysfs_remove_link(&root->sysdev.kobj,
95	kobject_name(&memory->sysdev.kobj));
96	}
97
98	/*
99	* use this as the physical section index that this memsection
100	* uses.
101	*/
102
103	static ssize_t show_mem_phys_index(struct sys_device dev, char buf)
104	{
105	struct memory_block *mem =
106	container_of(dev, struct memory_block, sysdev);
107	return sprintf(buf, "%08lx\n", mem->phys_index);
108	}
109
110	/*
111	* online, offline, going offline, etc.
112	*/
113	static ssize_t show_mem_state(struct sys_device dev, char buf)
114	{
115	struct memory_block *mem =
116	container_of(dev, struct memory_block, sysdev);
117	ssize_t len = 0;
118
119	/*
120	* We can probably put these states in a nice little array
121	* so that they're not open-coded
122	*/
123	switch (mem->state) {
124	case MEM_ONLINE:
125	len = sprintf(buf, "online\n");
126	break;
127	case MEM_OFFLINE:
128	len = sprintf(buf, "offline\n");
129	break;
130	case MEM_GOING_OFFLINE:
131	len = sprintf(buf, "going-offline\n");
132	break;
133	default:
134	len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
135	mem->state);
136	WARN_ON(1);
137	break;
138	}
139
140	return len;
141	}
142
143	static inline int memory_notify(unsigned long val, void *v)
144	{
145	return notifier_call_chain(&memory_chain, val, v);
146	}
147
148	/*
149	* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
150	* OK to have direct references to sparsemem variables in here.
151	*/
152	static int
153	memory_block_action(struct memory_block *mem, unsigned long action)
154	{
155	int i;
156	unsigned long psection;
157	unsigned long start_pfn, start_paddr;
158	struct page *first_page;
159	int ret;
160	int old_state = mem->state;
161
162	psection = mem->phys_index;
163	first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
164
165	/*
166	* The probe routines leave the pages reserved, just
167	* as the bootmem code does. Make sure they're still
168	* that way.
169	*/
170	if (action == MEM_ONLINE) {
171	for (i = 0; i < PAGES_PER_SECTION; i++) {
172	if (PageReserved(first_page+i))
173	continue;
174
175	printk(KERN_WARNING "section number %ld page number %d "
176	"not reserved, was it already online? \n",
177	psection, i);
178	return -EBUSY;
179	}
180	}
181
182	switch (action) {
183	case MEM_ONLINE:
184	start_pfn = page_to_pfn(first_page);
185	ret = online_pages(start_pfn, PAGES_PER_SECTION);
186	break;
187	case MEM_OFFLINE:
188	mem->state = MEM_GOING_OFFLINE;
189	memory_notify(MEM_GOING_OFFLINE, NULL);
190	start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
191	ret = remove_memory(start_paddr,
192	PAGES_PER_SECTION << PAGE_SHIFT);
193	if (ret) {
194	mem->state = old_state;
195	break;
196	}
197	memory_notify(MEM_MAPPING_INVALID, NULL);
198	break;
199	default:
200	printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
201	__FUNCTION__, mem, action, action);
202	WARN_ON(1);
203	ret = -EINVAL;
204	}
205	/*
206	* For now, only notify on successful memory operations
207	*/
208	if (!ret)
209	memory_notify(action, NULL);
210
211	return ret;
212	}
213
214	static int memory_block_change_state(struct memory_block *mem,
215	unsigned long to_state, unsigned long from_state_req)
216	{
217	int ret = 0;
218	down(&mem->state_sem);
219
220	if (mem->state != from_state_req) {
221	ret = -EINVAL;
222	goto out;
223	}
224
225	ret = memory_block_action(mem, to_state);
226	if (!ret)
227	mem->state = to_state;
228
229	out:
230	up(&mem->state_sem);
231	return ret;
232	}
233
234	static ssize_t
235	store_mem_state(struct sys_device dev, const char buf, size_t count)
236	{
237	struct memory_block *mem;
238	unsigned int phys_section_nr;
239	int ret = -EINVAL;
240
241	mem = container_of(dev, struct memory_block, sysdev);
242	phys_section_nr = mem->phys_index;
243
244	if (!valid_section_nr(phys_section_nr))
245	goto out;
246
247	if (!strncmp(buf, "online", min((int)count, 6)))
248	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
249	else if(!strncmp(buf, "offline", min((int)count, 7)))
250	ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
251	out:
252	if (ret)
253	return ret;
254	return count;
255	}
256
257	/*
258	* phys_device is a bad name for this. What I really want
259	* is a way to differentiate between memory ranges that
260	* are part of physical devices that constitute
261	* a complete removable unit or fru.
262	* i.e. do these ranges belong to the same physical device,
263	* s.t. if I offline all of these sections I can then
264	* remove the physical device?
265	*/
266	static ssize_t show_phys_device(struct sys_device dev, char buf)
267	{
268	struct memory_block *mem =
269	container_of(dev, struct memory_block, sysdev);
270	return sprintf(buf, "%d\n", mem->phys_device);
271	}
272
273	static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
274	static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
275	static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
276
277	#define mem_create_simple_file(mem, attr_name) \
278	sysdev_create_file(&mem->sysdev, &attr_##attr_name)
279	#define mem_remove_simple_file(mem, attr_name) \
280	sysdev_remove_file(&mem->sysdev, &attr_##attr_name)
281
282	/*
283	* Block size attribute stuff
284	*/
285	static ssize_t
286	print_block_size(struct class class, char buf)
287	{
288	return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
289	}
290
291	static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
292
293	static int block_size_init(void)
294	{
295	sysfs_create_file(&memory_sysdev_class.kset.kobj,
296	&class_attr_block_size_bytes.attr);
297	return 0;
298	}
299
300	/*
301	* Some architectures will have custom drivers to do this, and
302	* will not need to do it from userspace. The fake hot-add code
303	* as well as ppc64 will do all of their discovery in userspace
304	* and will require this interface.
305	*/
306	#ifdef CONFIG_ARCH_MEMORY_PROBE
307	static ssize_t
308	memory_probe_store(struct class class, const char __user buf, size_t count)
309	{
310	u64 phys_addr;
311	int ret;
312
313	phys_addr = simple_strtoull(buf, NULL, 0);
314
315	ret = add_memory(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
316
317	if (ret)
318	count = ret;
319
320	return count;
321	}
322	static CLASS_ATTR(probe, 0700, NULL, memory_probe_store);
323
324	static int memory_probe_init(void)
325	{
326	sysfs_create_file(&memory_sysdev_class.kset.kobj,
327	&class_attr_probe.attr);
328	return 0;
329	}
330	#else
331	#define memory_probe_init(...) do {} while (0)
332	#endif
333
334	/*
335	* Note that phys_device is optional. It is here to allow for
336	* differentiation between which physical devices each
337	* section belongs to...
338	*/
339
340	static int add_memory_block(unsigned long node_id, struct mem_section *section,
341	unsigned long state, int phys_device)
342	{
0b0acbec	343	struct memory_block mem = kzalloc(sizeof(mem), GFP_KERNEL);
3947be19 DH	344	int ret = 0;
	345
	346	if (!mem)
	347	return -ENOMEM;
	348
3947be19 DH	349	mem->phys_index = __section_nr(section);
	350	mem->state = state;
	351	init_MUTEX(&mem->state_sem);
	352	mem->phys_device = phys_device;
	353
	354	ret = register_memory(mem, section, NULL);
	355	if (!ret)
	356	ret = mem_create_simple_file(mem, phys_index);
	357	if (!ret)
	358	ret = mem_create_simple_file(mem, state);
	359	if (!ret)
	360	ret = mem_create_simple_file(mem, phys_device);
	361
	362	return ret;
	363	}
	364
	365	/*
	366	* For now, we have a linear search to go find the appropriate
	367	* memory_block corresponding to a particular phys_index. If
	368	* this gets to be a real problem, we can always use a radix
	369	* tree or something here.
	370	*
	371	* This could be made generic for all sysdev classes.
	372	*/
	373	static struct memory_block find_memory_block(struct mem_section section)
	374	{
	375	struct kobject *kobj;
	376	struct sys_device *sysdev;
	377	struct memory_block *mem;
	378	char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
	379
	380	/*
	381	* This only works because we know that section == sysdev->id
	382	* slightly redundant with sysdev_register()
	383	*/
	384	sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
	385
	386	kobj = kset_find_obj(&memory_sysdev_class.kset, name);
	387	if (!kobj)
	388	return NULL;
	389
	390	sysdev = container_of(kobj, struct sys_device, kobj);
	391	mem = container_of(sysdev, struct memory_block, sysdev);
	392
	393	return mem;
	394	}
	395
	396	int remove_memory_block(unsigned long node_id, struct mem_section *section,
	397	int phys_device)
	398	{
	399	struct memory_block *mem;
	400
	401	mem = find_memory_block(section);
	402	mem_remove_simple_file(mem, phys_index);
	403	mem_remove_simple_file(mem, state);
	404	mem_remove_simple_file(mem, phys_device);
	405	unregister_memory(mem, section, NULL);
	406
	407	return 0;
	408	}
	409
	410	/*
	411	* need an interface for the VM to add new memory regions,
	412	* but without onlining it.
413	*/
414	int register_new_memory(struct mem_section *section)
415	{
416	return add_memory_block(0, section, MEM_OFFLINE, 0);
417	}
418
419	int unregister_memory_section(struct mem_section *section)
420	{
421	if (!valid_section(section))
422	return -EINVAL;
423
424	return remove_memory_block(0, section, 0);
425	}
426
427	/*
428	* Initialize the sysfs support for memory devices...
429	*/
430	int __init memory_dev_init(void)
431	{
432	unsigned int i;
433	int ret;
434
435	memory_sysdev_class.kset.hotplug_ops = &memory_hotplug_ops;
436	ret = sysdev_class_register(&memory_sysdev_class);
437
438	/*
439	* Create entries for memory sections that were found
440	* during boot and have been initialized
441	*/
442	for (i = 0; i < NR_MEM_SECTIONS; i++) {
443	if (!valid_section_nr(i))
444	continue;
445	add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0);
446	}
447
448	memory_probe_init();
449	block_size_init();
450
451	return ret;
452	}