1 /*
2 * Memory subsystem 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/module.h>
14 #include <linux/init.h>
15 #include <linux/topology.h>
16 #include <linux/capability.h>
17 #include <linux/device.h>
18 #include <linux/memory.h>
19 #include <linux/memory_hotplug.h>
20 #include <linux/mm.h>
21 #include <linux/mutex.h>
22 #include <linux/stat.h>
23 #include <linux/slab.h>
24
25 #include <linux/atomic.h>
26 #include <asm/uaccess.h>
27
28 static DEFINE_MUTEX(mem_sysfs_mutex);
29
30 #define MEMORY_CLASS_NAME "memory"
31
32 #define to_memory_block(dev) container_of(dev, struct memory_block, dev)
33
34 static int sections_per_block;
35
base_memory_block_id(int section_nr)36 static inline int base_memory_block_id(int section_nr)
37 {
38 return section_nr / sections_per_block;
39 }
40
41 static int memory_subsys_online(struct device *dev);
42 static int memory_subsys_offline(struct device *dev);
43
44 static struct bus_type memory_subsys = {
45 .name = MEMORY_CLASS_NAME,
46 .dev_name = MEMORY_CLASS_NAME,
47 .online = memory_subsys_online,
48 .offline = memory_subsys_offline,
49 };
50
51 static BLOCKING_NOTIFIER_HEAD(memory_chain);
52
register_memory_notifier(struct notifier_block * nb)53 int register_memory_notifier(struct notifier_block *nb)
54 {
55 return blocking_notifier_chain_register(&memory_chain, nb);
56 }
57 EXPORT_SYMBOL(register_memory_notifier);
58
unregister_memory_notifier(struct notifier_block * nb)59 void unregister_memory_notifier(struct notifier_block *nb)
60 {
61 blocking_notifier_chain_unregister(&memory_chain, nb);
62 }
63 EXPORT_SYMBOL(unregister_memory_notifier);
64
65 static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
66
register_memory_isolate_notifier(struct notifier_block * nb)67 int register_memory_isolate_notifier(struct notifier_block *nb)
68 {
69 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
70 }
71 EXPORT_SYMBOL(register_memory_isolate_notifier);
72
unregister_memory_isolate_notifier(struct notifier_block * nb)73 void unregister_memory_isolate_notifier(struct notifier_block *nb)
74 {
75 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
76 }
77 EXPORT_SYMBOL(unregister_memory_isolate_notifier);
78
memory_block_release(struct device * dev)79 static void memory_block_release(struct device *dev)
80 {
81 struct memory_block *mem = to_memory_block(dev);
82
83 kfree(mem);
84 }
85
memory_block_size_bytes(void)86 unsigned long __weak memory_block_size_bytes(void)
87 {
88 return MIN_MEMORY_BLOCK_SIZE;
89 }
90
get_memory_block_size(void)91 static unsigned long get_memory_block_size(void)
92 {
93 unsigned long block_sz;
94
95 block_sz = memory_block_size_bytes();
96
97 /* Validate blk_sz is a power of 2 and not less than section size */
98 if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
99 WARN_ON(1);
100 block_sz = MIN_MEMORY_BLOCK_SIZE;
101 }
102
103 return block_sz;
104 }
105
106 /*
107 * use this as the physical section index that this memsection
108 * uses.
109 */
110
show_mem_start_phys_index(struct device * dev,struct device_attribute * attr,char * buf)111 static ssize_t show_mem_start_phys_index(struct device *dev,
112 struct device_attribute *attr, char *buf)
113 {
114 struct memory_block *mem = to_memory_block(dev);
115 unsigned long phys_index;
116
117 phys_index = mem->start_section_nr / sections_per_block;
118 return sprintf(buf, "%08lx\n", phys_index);
119 }
120
121 /*
122 * Show whether the section of memory is likely to be hot-removable
123 */
show_mem_removable(struct device * dev,struct device_attribute * attr,char * buf)124 static ssize_t show_mem_removable(struct device *dev,
125 struct device_attribute *attr, char *buf)
126 {
127 unsigned long i, pfn;
128 int ret = 1;
129 struct memory_block *mem = to_memory_block(dev);
130
131 for (i = 0; i < sections_per_block; i++) {
132 if (!present_section_nr(mem->start_section_nr + i))
133 continue;
134 pfn = section_nr_to_pfn(mem->start_section_nr + i);
135 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
136 }
137
138 return sprintf(buf, "%d\n", ret);
139 }
140
141 /*
142 * online, offline, going offline, etc.
143 */
show_mem_state(struct device * dev,struct device_attribute * attr,char * buf)144 static ssize_t show_mem_state(struct device *dev,
145 struct device_attribute *attr, char *buf)
146 {
147 struct memory_block *mem = to_memory_block(dev);
148 ssize_t len = 0;
149
150 /*
151 * We can probably put these states in a nice little array
152 * so that they're not open-coded
153 */
154 switch (mem->state) {
155 case MEM_ONLINE:
156 len = sprintf(buf, "online\n");
157 break;
158 case MEM_OFFLINE:
159 len = sprintf(buf, "offline\n");
160 break;
161 case MEM_GOING_OFFLINE:
162 len = sprintf(buf, "going-offline\n");
163 break;
164 default:
165 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
166 mem->state);
167 WARN_ON(1);
168 break;
169 }
170
171 return len;
172 }
173
memory_notify(unsigned long val,void * v)174 int memory_notify(unsigned long val, void *v)
175 {
176 return blocking_notifier_call_chain(&memory_chain, val, v);
177 }
178
memory_isolate_notify(unsigned long val,void * v)179 int memory_isolate_notify(unsigned long val, void *v)
180 {
181 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
182 }
183
184 /*
185 * The probe routines leave the pages reserved, just as the bootmem code does.
186 * Make sure they're still that way.
187 */
pages_correctly_reserved(unsigned long start_pfn)188 static bool pages_correctly_reserved(unsigned long start_pfn)
189 {
190 int i, j;
191 struct page *page;
192 unsigned long pfn = start_pfn;
193
194 /*
195 * memmap between sections is not contiguous except with
196 * SPARSEMEM_VMEMMAP. We lookup the page once per section
197 * and assume memmap is contiguous within each section
198 */
199 for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
200 if (WARN_ON_ONCE(!pfn_valid(pfn)))
201 return false;
202 page = pfn_to_page(pfn);
203
204 for (j = 0; j < PAGES_PER_SECTION; j++) {
205 if (PageReserved(page + j))
206 continue;
207
208 printk(KERN_WARNING "section number %ld page number %d "
209 "not reserved, was it already online?\n",
210 pfn_to_section_nr(pfn), j);
211
212 return false;
213 }
214 }
215
216 return true;
217 }
218
219 /*
220 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
221 * OK to have direct references to sparsemem variables in here.
222 * Must already be protected by mem_hotplug_begin().
223 */
224 static int
memory_block_action(unsigned long phys_index,unsigned long action,int online_type)225 memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
226 {
227 unsigned long start_pfn;
228 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
229 struct page *first_page;
230 int ret;
231
232 start_pfn = section_nr_to_pfn(phys_index);
233 first_page = pfn_to_page(start_pfn);
234
235 switch (action) {
236 case MEM_ONLINE:
237 if (!pages_correctly_reserved(start_pfn))
238 return -EBUSY;
239
240 ret = online_pages(start_pfn, nr_pages, online_type);
241 break;
242 case MEM_OFFLINE:
243 ret = offline_pages(start_pfn, nr_pages);
244 break;
245 default:
246 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
247 "%ld\n", __func__, phys_index, action, action);
248 ret = -EINVAL;
249 }
250
251 return ret;
252 }
253
memory_block_change_state(struct memory_block * mem,unsigned long to_state,unsigned long from_state_req)254 static int memory_block_change_state(struct memory_block *mem,
255 unsigned long to_state, unsigned long from_state_req)
256 {
257 int ret = 0;
258
259 if (mem->state != from_state_req)
260 return -EINVAL;
261
262 if (to_state == MEM_OFFLINE)
263 mem->state = MEM_GOING_OFFLINE;
264
265 ret = memory_block_action(mem->start_section_nr, to_state,
266 mem->online_type);
267
268 mem->state = ret ? from_state_req : to_state;
269
270 return ret;
271 }
272
273 /* The device lock serializes operations on memory_subsys_[online|offline] */
memory_subsys_online(struct device * dev)274 static int memory_subsys_online(struct device *dev)
275 {
276 struct memory_block *mem = to_memory_block(dev);
277 int ret;
278
279 if (mem->state == MEM_ONLINE)
280 return 0;
281
282 /*
283 * If we are called from store_mem_state(), online_type will be
284 * set >= 0 Otherwise we were called from the device online
285 * attribute and need to set the online_type.
286 */
287 if (mem->online_type < 0)
288 mem->online_type = MMOP_ONLINE_KEEP;
289
290 /* Already under protection of mem_hotplug_begin() */
291 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
292
293 /* clear online_type */
294 mem->online_type = -1;
295
296 return ret;
297 }
298
memory_subsys_offline(struct device * dev)299 static int memory_subsys_offline(struct device *dev)
300 {
301 struct memory_block *mem = to_memory_block(dev);
302
303 if (mem->state == MEM_OFFLINE)
304 return 0;
305
306 /* Can't offline block with non-present sections */
307 if (mem->section_count != sections_per_block)
308 return -EINVAL;
309
310 return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
311 }
312
313 static ssize_t
store_mem_state(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)314 store_mem_state(struct device *dev,
315 struct device_attribute *attr, const char *buf, size_t count)
316 {
317 struct memory_block *mem = to_memory_block(dev);
318 int ret, online_type;
319
320 ret = lock_device_hotplug_sysfs();
321 if (ret)
322 return ret;
323
324 if (sysfs_streq(buf, "online_kernel"))
325 online_type = MMOP_ONLINE_KERNEL;
326 else if (sysfs_streq(buf, "online_movable"))
327 online_type = MMOP_ONLINE_MOVABLE;
328 else if (sysfs_streq(buf, "online"))
329 online_type = MMOP_ONLINE_KEEP;
330 else if (sysfs_streq(buf, "offline"))
331 online_type = MMOP_OFFLINE;
332 else {
333 ret = -EINVAL;
334 goto err;
335 }
336
337 /*
338 * Memory hotplug needs to hold mem_hotplug_begin() for probe to find
339 * the correct memory block to online before doing device_online(dev),
340 * which will take dev->mutex. Take the lock early to prevent an
341 * inversion, memory_subsys_online() callbacks will be implemented by
342 * assuming it's already protected.
343 */
344 mem_hotplug_begin();
345
346 switch (online_type) {
347 case MMOP_ONLINE_KERNEL:
348 case MMOP_ONLINE_MOVABLE:
349 case MMOP_ONLINE_KEEP:
350 mem->online_type = online_type;
351 ret = device_online(&mem->dev);
352 break;
353 case MMOP_OFFLINE:
354 ret = device_offline(&mem->dev);
355 break;
356 default:
357 ret = -EINVAL; /* should never happen */
358 }
359
360 mem_hotplug_done();
361 err:
362 unlock_device_hotplug();
363
364 if (ret)
365 return ret;
366 return count;
367 }
368
369 /*
370 * phys_device is a bad name for this. What I really want
371 * is a way to differentiate between memory ranges that
372 * are part of physical devices that constitute
373 * a complete removable unit or fru.
374 * i.e. do these ranges belong to the same physical device,
375 * s.t. if I offline all of these sections I can then
376 * remove the physical device?
377 */
show_phys_device(struct device * dev,struct device_attribute * attr,char * buf)378 static ssize_t show_phys_device(struct device *dev,
379 struct device_attribute *attr, char *buf)
380 {
381 struct memory_block *mem = to_memory_block(dev);
382 return sprintf(buf, "%d\n", mem->phys_device);
383 }
384
385 #ifdef CONFIG_MEMORY_HOTREMOVE
show_valid_zones(struct device * dev,struct device_attribute * attr,char * buf)386 static ssize_t show_valid_zones(struct device *dev,
387 struct device_attribute *attr, char *buf)
388 {
389 struct memory_block *mem = to_memory_block(dev);
390 unsigned long start_pfn, end_pfn;
391 unsigned long valid_start, valid_end;
392 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
393 struct zone *zone;
394
395 start_pfn = section_nr_to_pfn(mem->start_section_nr);
396 end_pfn = start_pfn + nr_pages;
397
398 /* The block contains more than one zone can not be offlined. */
399 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
400 return sprintf(buf, "none\n");
401
402 zone = page_zone(pfn_to_page(valid_start));
403
404 if (zone_idx(zone) == ZONE_MOVABLE - 1) {
405 /*The mem block is the last memoryblock of this zone.*/
406 if (valid_end == zone_end_pfn(zone))
407 return sprintf(buf, "%s %s\n",
408 zone->name, (zone + 1)->name);
409 }
410
411 if (zone_idx(zone) == ZONE_MOVABLE) {
412 /*The mem block is the first memoryblock of ZONE_MOVABLE.*/
413 if (valid_start == zone->zone_start_pfn)
414 return sprintf(buf, "%s %s\n",
415 zone->name, (zone - 1)->name);
416 }
417
418 return sprintf(buf, "%s\n", zone->name);
419 }
420 static DEVICE_ATTR(valid_zones, 0444, show_valid_zones, NULL);
421 #endif
422
423 static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
424 static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
425 static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
426 static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
427
428 /*
429 * Block size attribute stuff
430 */
431 static ssize_t
print_block_size(struct device * dev,struct device_attribute * attr,char * buf)432 print_block_size(struct device *dev, struct device_attribute *attr,
433 char *buf)
434 {
435 return sprintf(buf, "%lx\n", get_memory_block_size());
436 }
437
438 static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
439
440 /*
441 * Some architectures will have custom drivers to do this, and
442 * will not need to do it from userspace. The fake hot-add code
443 * as well as ppc64 will do all of their discovery in userspace
444 * and will require this interface.
445 */
446 #ifdef CONFIG_ARCH_MEMORY_PROBE
447 static ssize_t
memory_probe_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)448 memory_probe_store(struct device *dev, struct device_attribute *attr,
449 const char *buf, size_t count)
450 {
451 u64 phys_addr;
452 int nid;
453 int i, ret;
454 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
455
456 ret = kstrtoull(buf, 0, &phys_addr);
457 if (ret)
458 return ret;
459
460 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
461 return -EINVAL;
462
463 for (i = 0; i < sections_per_block; i++) {
464 nid = memory_add_physaddr_to_nid(phys_addr);
465 ret = add_memory(nid, phys_addr,
466 PAGES_PER_SECTION << PAGE_SHIFT);
467 if (ret)
468 goto out;
469
470 phys_addr += MIN_MEMORY_BLOCK_SIZE;
471 }
472
473 ret = count;
474 out:
475 return ret;
476 }
477
478 static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
479 #endif
480
481 #ifdef CONFIG_MEMORY_FAILURE
482 /*
483 * Support for offlining pages of memory
484 */
485
486 /* Soft offline a page */
487 static ssize_t
store_soft_offline_page(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)488 store_soft_offline_page(struct device *dev,
489 struct device_attribute *attr,
490 const char *buf, size_t count)
491 {
492 int ret;
493 u64 pfn;
494 if (!capable(CAP_SYS_ADMIN))
495 return -EPERM;
496 if (kstrtoull(buf, 0, &pfn) < 0)
497 return -EINVAL;
498 pfn >>= PAGE_SHIFT;
499 if (!pfn_valid(pfn))
500 return -ENXIO;
501 ret = soft_offline_page(pfn_to_page(pfn), 0);
502 return ret == 0 ? count : ret;
503 }
504
505 /* Forcibly offline a page, including killing processes. */
506 static ssize_t
store_hard_offline_page(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)507 store_hard_offline_page(struct device *dev,
508 struct device_attribute *attr,
509 const char *buf, size_t count)
510 {
511 int ret;
512 u64 pfn;
513 if (!capable(CAP_SYS_ADMIN))
514 return -EPERM;
515 if (kstrtoull(buf, 0, &pfn) < 0)
516 return -EINVAL;
517 pfn >>= PAGE_SHIFT;
518 ret = memory_failure(pfn, 0, 0);
519 return ret ? ret : count;
520 }
521
522 static DEVICE_ATTR(soft_offline_page, S_IWUSR, NULL, store_soft_offline_page);
523 static DEVICE_ATTR(hard_offline_page, S_IWUSR, NULL, store_hard_offline_page);
524 #endif
525
526 /*
527 * Note that phys_device is optional. It is here to allow for
528 * differentiation between which *physical* devices each
529 * section belongs to...
530 */
arch_get_memory_phys_device(unsigned long start_pfn)531 int __weak arch_get_memory_phys_device(unsigned long start_pfn)
532 {
533 return 0;
534 }
535
536 /*
537 * A reference for the returned object is held and the reference for the
538 * hinted object is released.
539 */
find_memory_block_hinted(struct mem_section * section,struct memory_block * hint)540 struct memory_block *find_memory_block_hinted(struct mem_section *section,
541 struct memory_block *hint)
542 {
543 int block_id = base_memory_block_id(__section_nr(section));
544 struct device *hintdev = hint ? &hint->dev : NULL;
545 struct device *dev;
546
547 dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
548 if (hint)
549 put_device(&hint->dev);
550 if (!dev)
551 return NULL;
552 return to_memory_block(dev);
553 }
554
555 /*
556 * For now, we have a linear search to go find the appropriate
557 * memory_block corresponding to a particular phys_index. If
558 * this gets to be a real problem, we can always use a radix
559 * tree or something here.
560 *
561 * This could be made generic for all device subsystems.
562 */
find_memory_block(struct mem_section * section)563 struct memory_block *find_memory_block(struct mem_section *section)
564 {
565 return find_memory_block_hinted(section, NULL);
566 }
567
568 static struct attribute *memory_memblk_attrs[] = {
569 &dev_attr_phys_index.attr,
570 &dev_attr_state.attr,
571 &dev_attr_phys_device.attr,
572 &dev_attr_removable.attr,
573 #ifdef CONFIG_MEMORY_HOTREMOVE
574 &dev_attr_valid_zones.attr,
575 #endif
576 NULL
577 };
578
579 static struct attribute_group memory_memblk_attr_group = {
580 .attrs = memory_memblk_attrs,
581 };
582
583 static const struct attribute_group *memory_memblk_attr_groups[] = {
584 &memory_memblk_attr_group,
585 NULL,
586 };
587
588 /*
589 * register_memory - Setup a sysfs device for a memory block
590 */
591 static
register_memory(struct memory_block * memory)592 int register_memory(struct memory_block *memory)
593 {
594 memory->dev.bus = &memory_subsys;
595 memory->dev.id = memory->start_section_nr / sections_per_block;
596 memory->dev.release = memory_block_release;
597 memory->dev.groups = memory_memblk_attr_groups;
598 memory->dev.offline = memory->state == MEM_OFFLINE;
599
600 return device_register(&memory->dev);
601 }
602
init_memory_block(struct memory_block ** memory,struct mem_section * section,unsigned long state)603 static int init_memory_block(struct memory_block **memory,
604 struct mem_section *section, unsigned long state)
605 {
606 struct memory_block *mem;
607 unsigned long start_pfn;
608 int scn_nr;
609 int ret = 0;
610
611 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
612 if (!mem)
613 return -ENOMEM;
614
615 scn_nr = __section_nr(section);
616 mem->start_section_nr =
617 base_memory_block_id(scn_nr) * sections_per_block;
618 mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
619 mem->state = state;
620 mem->section_count++;
621 start_pfn = section_nr_to_pfn(mem->start_section_nr);
622 mem->phys_device = arch_get_memory_phys_device(start_pfn);
623
624 ret = register_memory(mem);
625
626 *memory = mem;
627 return ret;
628 }
629
add_memory_block(int base_section_nr)630 static int add_memory_block(int base_section_nr)
631 {
632 struct memory_block *mem;
633 int i, ret, section_count = 0, section_nr;
634
635 for (i = base_section_nr;
636 (i < base_section_nr + sections_per_block) && i < NR_MEM_SECTIONS;
637 i++) {
638 if (!present_section_nr(i))
639 continue;
640 if (section_count == 0)
641 section_nr = i;
642 section_count++;
643 }
644
645 if (section_count == 0)
646 return 0;
647 ret = init_memory_block(&mem, __nr_to_section(section_nr), MEM_ONLINE);
648 if (ret)
649 return ret;
650 mem->section_count = section_count;
651 return 0;
652 }
653
654
655 /*
656 * need an interface for the VM to add new memory regions,
657 * but without onlining it.
658 */
register_new_memory(int nid,struct mem_section * section)659 int register_new_memory(int nid, struct mem_section *section)
660 {
661 int ret = 0;
662 struct memory_block *mem;
663
664 mutex_lock(&mem_sysfs_mutex);
665
666 mem = find_memory_block(section);
667 if (mem) {
668 mem->section_count++;
669 put_device(&mem->dev);
670 } else {
671 ret = init_memory_block(&mem, section, MEM_OFFLINE);
672 if (ret)
673 goto out;
674 }
675
676 if (mem->section_count == sections_per_block)
677 ret = register_mem_sect_under_node(mem, nid);
678 out:
679 mutex_unlock(&mem_sysfs_mutex);
680 return ret;
681 }
682
683 #ifdef CONFIG_MEMORY_HOTREMOVE
684 static void
unregister_memory(struct memory_block * memory)685 unregister_memory(struct memory_block *memory)
686 {
687 BUG_ON(memory->dev.bus != &memory_subsys);
688
689 /* drop the ref. we got in remove_memory_block() */
690 put_device(&memory->dev);
691 device_unregister(&memory->dev);
692 }
693
remove_memory_block(unsigned long node_id,struct mem_section * section,int phys_device)694 static int remove_memory_block(unsigned long node_id,
695 struct mem_section *section, int phys_device)
696 {
697 struct memory_block *mem;
698
699 mutex_lock(&mem_sysfs_mutex);
700 mem = find_memory_block(section);
701 unregister_mem_sect_under_nodes(mem, __section_nr(section));
702
703 mem->section_count--;
704 if (mem->section_count == 0)
705 unregister_memory(mem);
706 else
707 put_device(&mem->dev);
708
709 mutex_unlock(&mem_sysfs_mutex);
710 return 0;
711 }
712
unregister_memory_section(struct mem_section * section)713 int unregister_memory_section(struct mem_section *section)
714 {
715 if (!present_section(section))
716 return -EINVAL;
717
718 return remove_memory_block(0, section, 0);
719 }
720 #endif /* CONFIG_MEMORY_HOTREMOVE */
721
722 /* return true if the memory block is offlined, otherwise, return false */
is_memblock_offlined(struct memory_block * mem)723 bool is_memblock_offlined(struct memory_block *mem)
724 {
725 return mem->state == MEM_OFFLINE;
726 }
727
728 static struct attribute *memory_root_attrs[] = {
729 #ifdef CONFIG_ARCH_MEMORY_PROBE
730 &dev_attr_probe.attr,
731 #endif
732
733 #ifdef CONFIG_MEMORY_FAILURE
734 &dev_attr_soft_offline_page.attr,
735 &dev_attr_hard_offline_page.attr,
736 #endif
737
738 &dev_attr_block_size_bytes.attr,
739 NULL
740 };
741
742 static struct attribute_group memory_root_attr_group = {
743 .attrs = memory_root_attrs,
744 };
745
746 static const struct attribute_group *memory_root_attr_groups[] = {
747 &memory_root_attr_group,
748 NULL,
749 };
750
751 /*
752 * Initialize the sysfs support for memory devices...
753 */
memory_dev_init(void)754 int __init memory_dev_init(void)
755 {
756 unsigned int i;
757 int ret;
758 int err;
759 unsigned long block_sz;
760
761 ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
762 if (ret)
763 goto out;
764
765 block_sz = get_memory_block_size();
766 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
767
768 /*
769 * Create entries for memory sections that were found
770 * during boot and have been initialized
771 */
772 mutex_lock(&mem_sysfs_mutex);
773 for (i = 0; i < NR_MEM_SECTIONS; i += sections_per_block) {
774 err = add_memory_block(i);
775 if (!ret)
776 ret = err;
777 }
778 mutex_unlock(&mem_sysfs_mutex);
779
780 out:
781 if (ret)
782 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
783 return ret;
784 }
785