mm/memory_hotplug.c

   1 /*
   2  *  linux/mm/memory_hotplug.c
   3  *
   4  *  Copyright (C)
   5  */
   6
   7 #include <linux/stddef.h>
   8 #include <linux/mm.h>
   9 #include <linux/swap.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/compiler.h>
  13 #include <linux/export.h>
  14 #include <linux/pagevec.h>
  15 #include <linux/writeback.h>
  16 #include <linux/slab.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/cpu.h>
  19 #include <linux/memory.h>
  20 #include <linux/memremap.h>
  21 #include <linux/memory_hotplug.h>
  22 #include <linux/highmem.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/ioport.h>
  25 #include <linux/delay.h>
  26 #include <linux/migrate.h>
  27 #include <linux/page-isolation.h>
  28 #include <linux/pfn.h>
  29 #include <linux/suspend.h>
  30 #include <linux/mm_inline.h>
  31 #include <linux/firmware-map.h>
  32 #include <linux/stop_machine.h>
  33 #include <linux/hugetlb.h>
  34 #include <linux/memblock.h>
  35 #include <linux/bootmem.h>
  36 #include <linux/compaction.h>
  37
  38 #include <asm/tlbflush.h>
  39
  40 #include "internal.h"
  41
  42 /*
  43  * online_page_callback contains pointer to current page onlining function.
  44  * Initially it is generic_online_page(). If it is required it could be
  45  * changed by calling set_online_page_callback() for callback registration
  46  * and restore_online_page_callback() for generic callback restore.
  47  */
  48
  49 static void generic_online_page(struct page *page);
  50
  51 static online_page_callback_t online_page_callback = generic_online_page;
  52 static DEFINE_MUTEX(online_page_callback_lock);
  53
  54 /* The same as the cpu_hotplug lock, but for memory hotplug. */
  55 static struct {
  56         struct task_struct *active_writer;
  57         struct mutex lock; /* Synchronizes accesses to refcount, */
  58         /*
  59          * Also blocks the new readers during
  60          * an ongoing mem hotplug operation.
  61          */
  62         int refcount;
  63
  64 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  65         struct lockdep_map dep_map;
  66 #endif
  67 } mem_hotplug = {
  68         .active_writer = NULL,
  69         .lock = __MUTEX_INITIALIZER(mem_hotplug.lock),
  70         .refcount = 0,
  71 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  72         .dep_map = {.name = "mem_hotplug.lock" },
  73 #endif
  74 };
  75
  76 /* Lockdep annotations for get/put_online_mems() and mem_hotplug_begin/end() */
  77 #define memhp_lock_acquire_read() lock_map_acquire_read(&mem_hotplug.dep_map)
  78 #define memhp_lock_acquire()      lock_map_acquire(&mem_hotplug.dep_map)
  79 #define memhp_lock_release()      lock_map_release(&mem_hotplug.dep_map)
  80
  81 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
  82 bool memhp_auto_online;
  83 #else
  84 bool memhp_auto_online = true;
  85 #endif
  86 EXPORT_SYMBOL_GPL(memhp_auto_online);
  87
  88 static int __init setup_memhp_default_state(char *str)
  89 {
  90         if (!strcmp(str, "online"))
  91                 memhp_auto_online = true;
  92         else if (!strcmp(str, "offline"))
  93                 memhp_auto_online = false;
  94
  95         return 1;
  96 }
  97 __setup("memhp_default_state=", setup_memhp_default_state);
  98
  99 void get_online_mems(void)
 100 {
 101         might_sleep();
 102         if (mem_hotplug.active_writer == current)
 103                 return;
 104         memhp_lock_acquire_read();
 105         mutex_lock(&mem_hotplug.lock);
 106         mem_hotplug.refcount++;
 107         mutex_unlock(&mem_hotplug.lock);
 108
 109 }
 110
 111 void put_online_mems(void)
 112 {
 113         if (mem_hotplug.active_writer == current)
 114                 return;
 115         mutex_lock(&mem_hotplug.lock);
 116
 117         if (WARN_ON(!mem_hotplug.refcount))
 118                 mem_hotplug.refcount++; /* try to fix things up */
 119
 120         if (!--mem_hotplug.refcount && unlikely(mem_hotplug.active_writer))
 121                 wake_up_process(mem_hotplug.active_writer);
 122         mutex_unlock(&mem_hotplug.lock);
 123         memhp_lock_release();
 124
 125 }
 126
 127 void mem_hotplug_begin(void)
 128 {
 129         mem_hotplug.active_writer = current;
 130
 131         memhp_lock_acquire();
 132         for (;;) {
 133                 mutex_lock(&mem_hotplug.lock);
 134                 if (likely(!mem_hotplug.refcount))
 135                         break;
 136                 __set_current_state(TASK_UNINTERRUPTIBLE);
 137                 mutex_unlock(&mem_hotplug.lock);
 138                 schedule();
 139         }
 140 }
 141
 142 void mem_hotplug_done(void)
 143 {
 144         mem_hotplug.active_writer = NULL;
 145         mutex_unlock(&mem_hotplug.lock);
 146         memhp_lock_release();
 147 }
 148
 149 /* add this memory to iomem resource */
 150 static struct resource *register_memory_resource(u64 start, u64 size)
 151 {
 152         struct resource *res;
 153         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 154         if (!res)
 155                 return ERR_PTR(-ENOMEM);
 156
 157         res->name = "System RAM";
 158         res->start = start;
 159         res->end = start + size - 1;
 160         res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 161         if (request_resource(&iomem_resource, res) < 0) {
 162                 pr_debug("System RAM resource %pR cannot be added\n", res);
 163                 kfree(res);
 164                 return ERR_PTR(-EEXIST);
 165         }
 166         return res;
 167 }
 168
 169 static void release_memory_resource(struct resource *res)
 170 {
 171         if (!res)
 172                 return;
 173         release_resource(res);
 174         kfree(res);
 175         return;
 176 }
 177
 178 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 179 void get_page_bootmem(unsigned long info,  struct page *page,
 180                       unsigned long type)
 181 {
 182         page->lru.next = (struct list_head *) type;
 183         SetPagePrivate(page);
 184         set_page_private(page, info);
 185         page_ref_inc(page);
 186 }
 187
 188 void put_page_bootmem(struct page *page)
 189 {
 190         unsigned long type;
 191
 192         type = (unsigned long) page->lru.next;
 193         BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
 194                type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
 195
 196         if (page_ref_dec_return(page) == 1) {
 197                 ClearPagePrivate(page);
 198                 set_page_private(page, 0);
 199                 INIT_LIST_HEAD(&page->lru);
 200                 free_reserved_page(page);
 201         }
 202 }
 203
 204 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
 205 #ifndef CONFIG_SPARSEMEM_VMEMMAP
 206 static void register_page_bootmem_info_section(unsigned long start_pfn)
 207 {
 208         unsigned long *usemap, mapsize, section_nr, i;
 209         struct mem_section *ms;
 210         struct page *page, *memmap;
 211
 212         section_nr = pfn_to_section_nr(start_pfn);
 213         ms = __nr_to_section(section_nr);
 214
 215         /* Get section's memmap address */
 216         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 217
 218         /*
 219          * Get page for the memmap's phys address
 220          * XXX: need more consideration for sparse_vmemmap...
 221          */
 222         page = virt_to_page(memmap);
 223         mapsize = sizeof(struct page) * PAGES_PER_SECTION;
 224         mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
 225
 226         /* remember memmap's page */
 227         for (i = 0; i < mapsize; i++, page++)
 228                 get_page_bootmem(section_nr, page, SECTION_INFO);
 229
 230         usemap = __nr_to_section(section_nr)->pageblock_flags;
 231         page = virt_to_page(usemap);
 232
 233         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 234
 235         for (i = 0; i < mapsize; i++, page++)
 236                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 237
 238 }
 239 #else /* CONFIG_SPARSEMEM_VMEMMAP */
 240 static void register_page_bootmem_info_section(unsigned long start_pfn)
 241 {
 242         unsigned long *usemap, mapsize, section_nr, i;
 243         struct mem_section *ms;
 244         struct page *page, *memmap;
 245
 246         if (!pfn_valid(start_pfn))
 247                 return;
 248
 249         section_nr = pfn_to_section_nr(start_pfn);
 250         ms = __nr_to_section(section_nr);
 251
 252         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 253
 254         register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
 255
 256         usemap = __nr_to_section(section_nr)->pageblock_flags;
 257         page = virt_to_page(usemap);
 258
 259         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 260
 261         for (i = 0; i < mapsize; i++, page++)
 262                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 263 }
 264 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 265
 266 void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
 267 {
 268         unsigned long i, pfn, end_pfn, nr_pages;
 269         int node = pgdat->node_id;
 270         struct page *page;
 271         struct zone *zone;
 272
 273         nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
 274         page = virt_to_page(pgdat);
 275
 276         for (i = 0; i < nr_pages; i++, page++)
 277                 get_page_bootmem(node, page, NODE_INFO);
 278
 279         zone = &pgdat->node_zones[0];
 280         for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
 281                 if (zone_is_initialized(zone)) {
 282                         nr_pages = zone->wait_table_hash_nr_entries
 283                                 * sizeof(wait_queue_head_t);
 284                         nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
 285                         page = virt_to_page(zone->wait_table);
 286
 287                         for (i = 0; i < nr_pages; i++, page++)
 288                                 get_page_bootmem(node, page, NODE_INFO);
 289                 }
 290         }
 291
 292         pfn = pgdat->node_start_pfn;
 293         end_pfn = pgdat_end_pfn(pgdat);
 294
 295         /* register section info */
 296         for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 297                 /*
 298                  * Some platforms can assign the same pfn to multiple nodes - on
 299                  * node0 as well as nodeN.  To avoid registering a pfn against
 300                  * multiple nodes we check that this pfn does not already
 301                  * reside in some other nodes.
 302                  */
 303                 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
 304                         register_page_bootmem_info_section(pfn);
 305         }
 306 }
 307 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
 308
 309 static void __meminit grow_zone_span(struct zone *zone, unsigned long start_pfn,
 310                                      unsigned long end_pfn)
 311 {
 312         unsigned long old_zone_end_pfn;
 313
 314         zone_span_writelock(zone);
 315
 316         old_zone_end_pfn = zone_end_pfn(zone);
 317         if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
 318                 zone->zone_start_pfn = start_pfn;
 319
 320         zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
 321                                 zone->zone_start_pfn;
 322
 323         zone_span_writeunlock(zone);
 324 }
 325
 326 static void resize_zone(struct zone *zone, unsigned long start_pfn,
 327                 unsigned long end_pfn)
 328 {
 329         zone_span_writelock(zone);
 330
 331         if (end_pfn - start_pfn) {
 332                 zone->zone_start_pfn = start_pfn;
 333                 zone->spanned_pages = end_pfn - start_pfn;
 334         } else {
 335                 /*
 336                  * make it consist as free_area_init_core(),
 337                  * if spanned_pages = 0, then keep start_pfn = 0
 338                  */
 339                 zone->zone_start_pfn = 0;
 340                 zone->spanned_pages = 0;
 341         }
 342
 343         zone_span_writeunlock(zone);
 344 }
 345
 346 static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
 347                 unsigned long end_pfn)
 348 {
 349         enum zone_type zid = zone_idx(zone);
 350         int nid = zone->zone_pgdat->node_id;
 351         unsigned long pfn;
 352
 353         for (pfn = start_pfn; pfn < end_pfn; pfn++)
 354                 set_page_links(pfn_to_page(pfn), zid, nid, pfn);
 355 }
 356
 357 /* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
 358  * alloc_bootmem_node_nopanic()/memblock_virt_alloc_node_nopanic() */
 359 static int __ref ensure_zone_is_initialized(struct zone *zone,
 360                         unsigned long start_pfn, unsigned long num_pages)
 361 {
 362         if (!zone_is_initialized(zone))
 363                 return init_currently_empty_zone(zone, start_pfn, num_pages);
 364
 365         return 0;
 366 }
 367
 368 static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
 369                 unsigned long start_pfn, unsigned long end_pfn)
 370 {
 371         int ret;
 372         unsigned long flags;
 373         unsigned long z1_start_pfn;
 374
 375         ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
 376         if (ret)
 377                 return ret;
 378
 379         pgdat_resize_lock(z1->zone_pgdat, &flags);
 380
 381         /* can't move pfns which are higher than @z2 */
 382         if (end_pfn > zone_end_pfn(z2))
 383                 goto out_fail;
 384         /* the move out part must be at the left most of @z2 */
 385         if (start_pfn > z2->zone_start_pfn)
 386                 goto out_fail;
 387         /* must included/overlap */
 388         if (end_pfn <= z2->zone_start_pfn)
 389                 goto out_fail;
 390
 391         /* use start_pfn for z1's start_pfn if z1 is empty */
 392         if (!zone_is_empty(z1))
 393                 z1_start_pfn = z1->zone_start_pfn;
 394         else
 395                 z1_start_pfn = start_pfn;
 396
 397         resize_zone(z1, z1_start_pfn, end_pfn);
 398         resize_zone(z2, end_pfn, zone_end_pfn(z2));
 399
 400         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 401
 402         fix_zone_id(z1, start_pfn, end_pfn);
 403
 404         return 0;
 405 out_fail:
 406         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 407         return -1;
 408 }
 409
 410 static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
 411                 unsigned long start_pfn, unsigned long end_pfn)
 412 {
 413         int ret;
 414         unsigned long flags;
 415         unsigned long z2_end_pfn;
 416
 417         ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
 418         if (ret)
 419                 return ret;
 420
 421         pgdat_resize_lock(z1->zone_pgdat, &flags);
 422
 423         /* can't move pfns which are lower than @z1 */
 424         if (z1->zone_start_pfn > start_pfn)
 425                 goto out_fail;
 426         /* the move out part mast at the right most of @z1 */
 427         if (zone_end_pfn(z1) >  end_pfn)
 428                 goto out_fail;
 429         /* must included/overlap */
 430         if (start_pfn >= zone_end_pfn(z1))
 431                 goto out_fail;
 432
 433         /* use end_pfn for z2's end_pfn if z2 is empty */
 434         if (!zone_is_empty(z2))
 435                 z2_end_pfn = zone_end_pfn(z2);
 436         else
 437                 z2_end_pfn = end_pfn;
 438
 439         resize_zone(z1, z1->zone_start_pfn, start_pfn);
 440         resize_zone(z2, start_pfn, z2_end_pfn);
 441
 442         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 443
 444         fix_zone_id(z2, start_pfn, end_pfn);
 445
 446         return 0;
 447 out_fail:
 448         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 449         return -1;
 450 }
 451
 452 static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
 453                                       unsigned long end_pfn)
 454 {
 455         unsigned long old_pgdat_end_pfn = pgdat_end_pfn(pgdat);
 456
 457         if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
 458                 pgdat->node_start_pfn = start_pfn;
 459
 460         pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
 461                                         pgdat->node_start_pfn;
 462 }
 463
 464 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 465 {
 466         struct pglist_data *pgdat = zone->zone_pgdat;
 467         int nr_pages = PAGES_PER_SECTION;
 468         int nid = pgdat->node_id;
 469         int zone_type;
 470         unsigned long flags, pfn;
 471         int ret;
 472
 473         zone_type = zone - pgdat->node_zones;
 474         ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
 475         if (ret)
 476                 return ret;
 477
 478         pgdat_resize_lock(zone->zone_pgdat, &flags);
 479         grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
 480         grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
 481                         phys_start_pfn + nr_pages);
 482         pgdat_resize_unlock(zone->zone_pgdat, &flags);
 483         memmap_init_zone(nr_pages, nid, zone_type,
 484                          phys_start_pfn, MEMMAP_HOTPLUG);
 485
 486         /* online_page_range is called later and expects pages reserved */
 487         for (pfn = phys_start_pfn; pfn < phys_start_pfn + nr_pages; pfn++) {
 488                 if (!pfn_valid(pfn))
 489                         continue;
 490
 491                 SetPageReserved(pfn_to_page(pfn));
 492         }
 493         return 0;
 494 }
 495
 496 static int __meminit __add_section(int nid, struct zone *zone,
 497                                         unsigned long phys_start_pfn)
 498 {
 499         int ret;
 500
 501         if (pfn_valid(phys_start_pfn))
 502                 return -EEXIST;
 503
 504         ret = sparse_add_one_section(zone, phys_start_pfn);
 505
 506         if (ret < 0)
 507                 return ret;
 508
 509         ret = __add_zone(zone, phys_start_pfn);
 510
 511         if (ret < 0)
 512                 return ret;
 513
 514         return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 515 }
 516
 517 /*
 518  * Reasonably generic function for adding memory.  It is
 519  * expected that archs that support memory hotplug will
 520  * call this function after deciding the zone to which to
 521  * add the new pages.
 522  */
 523 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 524                         unsigned long nr_pages)
 525 {
 526         unsigned long i;
 527         int err = 0;
 528         int start_sec, end_sec;
 529         struct vmem_altmap *altmap;
 530
 531         clear_zone_contiguous(zone);
 532
 533         /* during initialize mem_map, align hot-added range to section */
 534         start_sec = pfn_to_section_nr(phys_start_pfn);
 535         end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 536
 537         altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
 538         if (altmap) {
 539                 /*
 540                  * Validate altmap is within bounds of the total request
 541                  */
 542                 if (altmap->base_pfn != phys_start_pfn
 543                                 || vmem_altmap_offset(altmap) > nr_pages) {
 544                         pr_warn_once("memory add fail, invalid altmap\n");
 545                         err = -EINVAL;
 546                         goto out;
 547                 }
 548                 altmap->alloc = 0;
 549         }
 550
 551         for (i = start_sec; i <= end_sec; i++) {
 552                 err = __add_section(nid, zone, section_nr_to_pfn(i));
 553
 554                 /*
 555                  * EEXIST is finally dealt with by ioresource collision
 556                  * check. see add_memory() => register_memory_resource()
 557                  * Warning will be printed if there is collision.
 558                  */
 559                 if (err && (err != -EEXIST))
 560                         break;
 561                 err = 0;
 562         }
 563         vmemmap_populate_print_last();
 564 out:
 565         set_zone_contiguous(zone);
 566         return err;
 567 }
 568 EXPORT_SYMBOL_GPL(__add_pages);
 569
 570 #ifdef CONFIG_MEMORY_HOTREMOVE
 571 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
 572 static int find_smallest_section_pfn(int nid, struct zone *zone,
 573                                      unsigned long start_pfn,
 574                                      unsigned long end_pfn)
 575 {
 576         struct mem_section *ms;
 577
 578         for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
 579                 ms = __pfn_to_section(start_pfn);
 580
 581                 if (unlikely(!valid_section(ms)))
 582                         continue;
 583
 584                 if (unlikely(pfn_to_nid(start_pfn) != nid))
 585                         continue;
 586
 587                 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
 588                         continue;
 589
 590                 return start_pfn;
 591         }
 592
 593         return 0;
 594 }
 595
 596 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
 597 static int find_biggest_section_pfn(int nid, struct zone *zone,
 598                                     unsigned long start_pfn,
 599                                     unsigned long end_pfn)
 600 {
 601         struct mem_section *ms;
 602         unsigned long pfn;
 603
 604         /* pfn is the end pfn of a memory section. */
 605         pfn = end_pfn - 1;
 606         for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
 607                 ms = __pfn_to_section(pfn);
 608
 609                 if (unlikely(!valid_section(ms)))
 610                         continue;
 611
 612                 if (unlikely(pfn_to_nid(pfn) != nid))
 613                         continue;
 614
 615                 if (zone && zone != page_zone(pfn_to_page(pfn)))
 616                         continue;
 617
 618                 return pfn;
 619         }
 620
 621         return 0;
 622 }
 623
 624 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
 625                              unsigned long end_pfn)
 626 {
 627         unsigned long zone_start_pfn = zone->zone_start_pfn;
 628         unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
 629         unsigned long zone_end_pfn = z;
 630         unsigned long pfn;
 631         struct mem_section *ms;
 632         int nid = zone_to_nid(zone);
 633
 634         zone_span_writelock(zone);
 635         if (zone_start_pfn == start_pfn) {
 636                 /*
 637                  * If the section is smallest section in the zone, it need
 638                  * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
 639                  * In this case, we find second smallest valid mem_section
 640                  * for shrinking zone.
 641                  */
 642                 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
 643                                                 zone_end_pfn);
 644                 if (pfn) {
 645                         zone->zone_start_pfn = pfn;
 646                         zone->spanned_pages = zone_end_pfn - pfn;
 647                 }
 648         } else if (zone_end_pfn == end_pfn) {
 649                 /*
 650                  * If the section is biggest section in the zone, it need
 651                  * shrink zone->spanned_pages.
 652                  * In this case, we find second biggest valid mem_section for
 653                  * shrinking zone.
 654                  */
 655                 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
 656                                                start_pfn);
 657                 if (pfn)
 658                         zone->spanned_pages = pfn - zone_start_pfn + 1;
 659         }
 660
 661         /*
 662          * The section is not biggest or smallest mem_section in the zone, it
 663          * only creates a hole in the zone. So in this case, we need not
 664          * change the zone. But perhaps, the zone has only hole data. Thus
 665          * it check the zone has only hole or not.
 666          */
 667         pfn = zone_start_pfn;
 668         for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
 669                 ms = __pfn_to_section(pfn);
 670
 671                 if (unlikely(!valid_section(ms)))
 672                         continue;
 673
 674                 if (page_zone(pfn_to_page(pfn)) != zone)
 675                         continue;
 676
 677                  /* If the section is current section, it continues the loop */
 678                 if (start_pfn == pfn)
 679                         continue;
 680
 681                 /* If we find valid section, we have nothing to do */
 682                 zone_span_writeunlock(zone);
 683                 return;
 684         }
 685
 686         /* The zone has no valid section */
 687         zone->zone_start_pfn = 0;
 688         zone->spanned_pages = 0;
 689         zone_span_writeunlock(zone);
 690 }
 691
 692 static void shrink_pgdat_span(struct pglist_data *pgdat,
 693                               unsigned long start_pfn, unsigned long end_pfn)
 694 {
 695         unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
 696         unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
 697         unsigned long pgdat_end_pfn = p;
 698         unsigned long pfn;
 699         struct mem_section *ms;
 700         int nid = pgdat->node_id;
 701
 702         if (pgdat_start_pfn == start_pfn) {
 703                 /*
 704                  * If the section is smallest section in the pgdat, it need
 705                  * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
 706                  * In this case, we find second smallest valid mem_section
 707                  * for shrinking zone.
 708                  */
 709                 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
 710                                                 pgdat_end_pfn);
 711                 if (pfn) {
 712                         pgdat->node_start_pfn = pfn;
 713                         pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
 714                 }
 715         } else if (pgdat_end_pfn == end_pfn) {
 716                 /*
 717                  * If the section is biggest section in the pgdat, it need
 718                  * shrink pgdat->node_spanned_pages.
 719                  * In this case, we find second biggest valid mem_section for
 720                  * shrinking zone.
 721                  */
 722                 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
 723                                                start_pfn);
 724                 if (pfn)
 725                         pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
 726         }
 727
 728         /*
 729          * If the section is not biggest or smallest mem_section in the pgdat,
 730          * it only creates a hole in the pgdat. So in this case, we need not
 731          * change the pgdat.
 732          * But perhaps, the pgdat has only hole data. Thus it check the pgdat
 733          * has only hole or not.
 734          */
 735         pfn = pgdat_start_pfn;
 736         for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
 737                 ms = __pfn_to_section(pfn);
 738
 739                 if (unlikely(!valid_section(ms)))
 740                         continue;
 741
 742                 if (pfn_to_nid(pfn) != nid)
 743                         continue;
 744
 745                  /* If the section is current section, it continues the loop */
 746                 if (start_pfn == pfn)
 747                         continue;
 748
 749                 /* If we find valid section, we have nothing to do */
 750                 return;
 751         }
 752
 753         /* The pgdat has no valid section */
 754         pgdat->node_start_pfn = 0;
 755         pgdat->node_spanned_pages = 0;
 756 }
 757
 758 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
 759 {
 760         struct pglist_data *pgdat = zone->zone_pgdat;
 761         int nr_pages = PAGES_PER_SECTION;
 762         int zone_type;
 763         unsigned long flags;
 764
 765         zone_type = zone - pgdat->node_zones;
 766
 767         pgdat_resize_lock(zone->zone_pgdat, &flags);
 768         shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
 769         shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
 770         pgdat_resize_unlock(zone->zone_pgdat, &flags);
 771 }
 772
 773 static int __remove_section(struct zone *zone, struct mem_section *ms,
 774                 unsigned long map_offset)
 775 {
 776         unsigned long start_pfn;
 777         int scn_nr;
 778         int ret = -EINVAL;
 779
 780         if (!valid_section(ms))
 781                 return ret;
 782
 783         ret = unregister_memory_section(ms);
 784         if (ret)
 785                 return ret;
 786
 787         scn_nr = __section_nr(ms);
 788         start_pfn = section_nr_to_pfn(scn_nr);
 789         __remove_zone(zone, start_pfn);
 790
 791         sparse_remove_one_section(zone, ms, map_offset);
 792         return 0;
 793 }
 794
 795 /**
 796  * __remove_pages() - remove sections of pages from a zone
 797  * @zone: zone from which pages need to be removed
 798  * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
 799  * @nr_pages: number of pages to remove (must be multiple of section size)
 800  *
 801  * Generic helper function to remove section mappings and sysfs entries
 802  * for the section of the memory we are removing. Caller needs to make
 803  * sure that pages are marked reserved and zones are adjust properly by
 804  * calling offline_pages().
 805  */
 806 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 807                  unsigned long nr_pages)
 808 {
 809         unsigned long i;
 810         unsigned long map_offset = 0;
 811         int sections_to_remove, ret = 0;
 812
 813         /* In the ZONE_DEVICE case device driver owns the memory region */
 814         if (is_dev_zone(zone)) {
 815                 struct page *page = pfn_to_page(phys_start_pfn);
 816                 struct vmem_altmap *altmap;
 817
 818                 altmap = to_vmem_altmap((unsigned long) page);
 819                 if (altmap)
 820                         map_offset = vmem_altmap_offset(altmap);
 821         } else {
 822                 resource_size_t start, size;
 823
 824                 start = phys_start_pfn << PAGE_SHIFT;
 825                 size = nr_pages * PAGE_SIZE;
 826
 827                 ret = release_mem_region_adjustable(&iomem_resource, start,
 828                                         size);
 829                 if (ret) {
 830                         resource_size_t endres = start + size - 1;
 831
 832                         pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
 833                                         &start, &endres, ret);
 834                 }
 835         }
 836
 837         clear_zone_contiguous(zone);
 838
 839         /*
 840          * We can only remove entire sections
 841          */
 842         BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 843         BUG_ON(nr_pages % PAGES_PER_SECTION);
 844
 845         sections_to_remove = nr_pages / PAGES_PER_SECTION;
 846         for (i = 0; i < sections_to_remove; i++) {
 847                 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 848
 849                 ret = __remove_section(zone, __pfn_to_section(pfn), map_offset);
 850                 map_offset = 0;
 851                 if (ret)
 852                         break;
 853         }
 854
 855         set_zone_contiguous(zone);
 856
 857         return ret;
 858 }
 859 EXPORT_SYMBOL_GPL(__remove_pages);
 860 #endif /* CONFIG_MEMORY_HOTREMOVE */
 861
 862 int set_online_page_callback(online_page_callback_t callback)
 863 {
 864         int rc = -EINVAL;
 865
 866         get_online_mems();
 867         mutex_lock(&online_page_callback_lock);
 868
 869         if (online_page_callback == generic_online_page) {
 870                 online_page_callback = callback;
 871                 rc = 0;
 872         }
 873
 874         mutex_unlock(&online_page_callback_lock);
 875         put_online_mems();
 876
 877         return rc;
 878 }
 879 EXPORT_SYMBOL_GPL(set_online_page_callback);
 880
 881 int restore_online_page_callback(online_page_callback_t callback)
 882 {
 883         int rc = -EINVAL;
 884
 885         get_online_mems();
 886         mutex_lock(&online_page_callback_lock);
 887
 888         if (online_page_callback == callback) {
 889                 online_page_callback = generic_online_page;
 890                 rc = 0;
 891         }
 892
 893         mutex_unlock(&online_page_callback_lock);
 894         put_online_mems();
 895
 896         return rc;
 897 }
 898 EXPORT_SYMBOL_GPL(restore_online_page_callback);
 899
 900 void __online_page_set_limits(struct page *page)
 901 {
 902 }
 903 EXPORT_SYMBOL_GPL(__online_page_set_limits);
 904
 905 void __online_page_increment_counters(struct page *page)
 906 {
 907         adjust_managed_page_count(page, 1);
 908 }
 909 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
 910
 911 void __online_page_free(struct page *page)
 912 {
 913         __free_reserved_page(page);
 914 }
 915 EXPORT_SYMBOL_GPL(__online_page_free);
 916
 917 static void generic_online_page(struct page *page)
 918 {
 919         __online_page_set_limits(page);
 920         __online_page_increment_counters(page);
 921         __online_page_free(page);
 922 }
 923
 924 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 925                         void *arg)
 926 {
 927         unsigned long i;
 928         unsigned long onlined_pages = *(unsigned long *)arg;
 929         struct page *page;
 930         if (PageReserved(pfn_to_page(start_pfn)))
 931                 for (i = 0; i < nr_pages; i++) {
 932                         page = pfn_to_page(start_pfn + i);
 933                         (*online_page_callback)(page);
 934                         onlined_pages++;
 935                 }
 936         *(unsigned long *)arg = onlined_pages;
 937         return 0;
 938 }
 939
 940 #ifdef CONFIG_MOVABLE_NODE
 941 /*
 942  * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
 943  * normal memory.
 944  */
 945 static bool can_online_high_movable(struct zone *zone)
 946 {
 947         return true;
 948 }
 949 #else /* CONFIG_MOVABLE_NODE */
 950 /* ensure every online node has NORMAL memory */
 951 static bool can_online_high_movable(struct zone *zone)
 952 {
 953         return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
 954 }
 955 #endif /* CONFIG_MOVABLE_NODE */
 956
 957 /* check which state of node_states will be changed when online memory */
 958 static void node_states_check_changes_online(unsigned long nr_pages,
 959         struct zone *zone, struct memory_notify *arg)
 960 {
 961         int nid = zone_to_nid(zone);
 962         enum zone_type zone_last = ZONE_NORMAL;
 963
 964         /*
 965          * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
 966          * contains nodes which have zones of 0...ZONE_NORMAL,
 967          * set zone_last to ZONE_NORMAL.
 968          *
 969          * If we don't have HIGHMEM nor movable node,
 970          * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
 971          * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
 972          */
 973         if (N_MEMORY == N_NORMAL_MEMORY)
 974                 zone_last = ZONE_MOVABLE;
 975
 976         /*
 977          * if the memory to be online is in a zone of 0...zone_last, and
 978          * the zones of 0...zone_last don't have memory before online, we will
 979          * need to set the node to node_states[N_NORMAL_MEMORY] after
 980          * the memory is online.
 981          */
 982         if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
 983                 arg->status_change_nid_normal = nid;
 984         else
 985                 arg->status_change_nid_normal = -1;
 986
 987 #ifdef CONFIG_HIGHMEM
 988         /*
 989          * If we have movable node, node_states[N_HIGH_MEMORY]
 990          * contains nodes which have zones of 0...ZONE_HIGHMEM,
 991          * set zone_last to ZONE_HIGHMEM.
 992          *
 993          * If we don't have movable node, node_states[N_NORMAL_MEMORY]
 994          * contains nodes which have zones of 0...ZONE_MOVABLE,
 995          * set zone_last to ZONE_MOVABLE.
 996          */
 997         zone_last = ZONE_HIGHMEM;
 998         if (N_MEMORY == N_HIGH_MEMORY)
 999                 zone_last = ZONE_MOVABLE;
1000
1001         if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
1002                 arg->status_change_nid_high = nid;
1003         else
1004                 arg->status_change_nid_high = -1;
1005 #else
1006         arg->status_change_nid_high = arg->status_change_nid_normal;
1007 #endif
1008
1009         /*
1010          * if the node don't have memory befor online, we will need to
1011          * set the node to node_states[N_MEMORY] after the memory
1012          * is online.
1013          */
1014         if (!node_state(nid, N_MEMORY))
1015                 arg->status_change_nid = nid;
1016         else
1017                 arg->status_change_nid = -1;
1018 }
1019
1020 static void node_states_set_node(int node, struct memory_notify *arg)
1021 {
1022         if (arg->status_change_nid_normal >= 0)
1023                 node_set_state(node, N_NORMAL_MEMORY);
1024
1025         if (arg->status_change_nid_high >= 0)
1026                 node_set_state(node, N_HIGH_MEMORY);
1027
1028         node_set_state(node, N_MEMORY);
1029 }
1030
1031
1032 /* Must be protected by mem_hotplug_begin() */
1033 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
1034 {
1035         unsigned long flags;
1036         unsigned long onlined_pages = 0;
1037         struct zone *zone;
1038         int need_zonelists_rebuild = 0;
1039         int nid;
1040         int ret;
1041         struct memory_notify arg;
1042
1043         /*
1044          * This doesn't need a lock to do pfn_to_page().
1045          * The section can't be removed here because of the
1046          * memory_block->state_mutex.
1047          */
1048         zone = page_zone(pfn_to_page(pfn));
1049
1050         if ((zone_idx(zone) > ZONE_NORMAL ||
1051             online_type == MMOP_ONLINE_MOVABLE) &&
1052             !can_online_high_movable(zone))
1053                 return -EINVAL;
1054
1055         if (online_type == MMOP_ONLINE_KERNEL &&
1056             zone_idx(zone) == ZONE_MOVABLE) {
1057                 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
1058                         return -EINVAL;
1059         }
1060         if (online_type == MMOP_ONLINE_MOVABLE &&
1061             zone_idx(zone) == ZONE_MOVABLE - 1) {
1062                 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
1063                         return -EINVAL;
1064         }
1065
1066         /* Previous code may changed the zone of the pfn range */
1067         zone = page_zone(pfn_to_page(pfn));
1068
1069         arg.start_pfn = pfn;
1070         arg.nr_pages = nr_pages;
1071         node_states_check_changes_online(nr_pages, zone, &arg);
1072
1073         nid = zone_to_nid(zone);
1074
1075         ret = memory_notify(MEM_GOING_ONLINE, &arg);
1076         ret = notifier_to_errno(ret);
1077         if (ret)
1078                 goto failed_addition;
1079
1080         /*
1081          * If this zone is not populated, then it is not in zonelist.
1082          * This means the page allocator ignores this zone.
1083          * So, zonelist must be updated after online.
1084          */
1085         mutex_lock(&zonelists_mutex);
1086         if (!populated_zone(zone)) {
1087                 need_zonelists_rebuild = 1;
1088                 build_all_zonelists(NULL, zone);
1089         }
1090
1091         ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
1092                 online_pages_range);
1093         if (ret) {
1094                 if (need_zonelists_rebuild)
1095                         zone_pcp_reset(zone);
1096                 mutex_unlock(&zonelists_mutex);
1097                 goto failed_addition;
1098         }
1099
1100         zone->present_pages += onlined_pages;
1101
1102         pgdat_resize_lock(zone->zone_pgdat, &flags);
1103         zone->zone_pgdat->node_present_pages += onlined_pages;
1104         pgdat_resize_unlock(zone->zone_pgdat, &flags);
1105
1106         if (onlined_pages) {
1107                 node_states_set_node(nid, &arg);
1108                 if (need_zonelists_rebuild)
1109                         build_all_zonelists(NULL, NULL);
1110                 else
1111                         zone_pcp_update(zone);
1112         }
1113
1114         mutex_unlock(&zonelists_mutex);
1115
1116         init_per_zone_wmark_min();
1117
1118         if (onlined_pages) {
1119                 kswapd_run(nid);
1120                 kcompactd_run(nid);
1121         }
1122
1123         vm_total_pages = nr_free_pagecache_pages();
1124
1125         writeback_set_ratelimit();
1126
1127         if (onlined_pages)
1128                 memory_notify(MEM_ONLINE, &arg);
1129         return 0;
1130
1131 failed_addition:
1132         pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1133                  (unsigned long long) pfn << PAGE_SHIFT,
1134                  (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1135         memory_notify(MEM_CANCEL_ONLINE, &arg);
1136         return ret;
1137 }
1138 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1139
1140 static void reset_node_present_pages(pg_data_t *pgdat)
1141 {
1142         struct zone *z;
1143
1144         for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
1145                 z->present_pages = 0;
1146
1147         pgdat->node_present_pages = 0;
1148 }
1149
1150 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1151 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1152 {
1153         struct pglist_data *pgdat;
1154         unsigned long zones_size[MAX_NR_ZONES] = {0};
1155         unsigned long zholes_size[MAX_NR_ZONES] = {0};
1156         unsigned long start_pfn = PFN_DOWN(start);
1157
1158         pgdat = NODE_DATA(nid);
1159         if (!pgdat) {
1160                 pgdat = arch_alloc_nodedata(nid);
1161                 if (!pgdat)
1162                         return NULL;
1163
1164                 arch_refresh_nodedata(nid, pgdat);
1165         } else {
1166                 /* Reset the nr_zones and classzone_idx to 0 before reuse */
1167                 pgdat->nr_zones = 0;
1168                 pgdat->classzone_idx = 0;
1169         }
1170
1171         /* we can use NODE_DATA(nid) from here */
1172
1173         /* init node's zones as empty zones, we don't have any present pages.*/
1174         free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1175
1176         /*
1177          * The node we allocated has no zone fallback lists. For avoiding
1178          * to access not-initialized zonelist, build here.
1179          */
1180         mutex_lock(&zonelists_mutex);
1181         build_all_zonelists(pgdat, NULL);
1182         mutex_unlock(&zonelists_mutex);
1183
1184         /*
1185          * zone->managed_pages is set to an approximate value in
1186          * free_area_init_core(), which will cause
1187          * /sys/device/system/node/nodeX/meminfo has wrong data.
1188          * So reset it to 0 before any memory is onlined.
1189          */
1190         reset_node_managed_pages(pgdat);
1191
1192         /*
1193          * When memory is hot-added, all the memory is in offline state. So
1194          * clear all zones' present_pages because they will be updated in
1195          * online_pages() and offline_pages().
1196          */
1197         reset_node_present_pages(pgdat);
1198
1199         return pgdat;
1200 }
1201
1202 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1203 {
1204         arch_refresh_nodedata(nid, NULL);
1205         arch_free_nodedata(pgdat);
1206         return;
1207 }
1208
1209
1210 /**
1211  * try_online_node - online a node if offlined
1212  *
1213  * called by cpu_up() to online a node without onlined memory.
1214  */
1215 int try_online_node(int nid)
1216 {
1217         pg_data_t       *pgdat;
1218         int     ret;
1219
1220         if (node_online(nid))
1221                 return 0;
1222
1223         mem_hotplug_begin();
1224         pgdat = hotadd_new_pgdat(nid, 0);
1225         if (!pgdat) {
1226                 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1227                 ret = -ENOMEM;
1228                 goto out;
1229         }
1230         node_set_online(nid);
1231         ret = register_one_node(nid);
1232         BUG_ON(ret);
1233
1234         if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
1235                 mutex_lock(&zonelists_mutex);
1236                 build_all_zonelists(NULL, NULL);
1237                 mutex_unlock(&zonelists_mutex);
1238         }
1239
1240 out:
1241         mem_hotplug_done();
1242         return ret;
1243 }
1244
1245 static int check_hotplug_memory_range(u64 start, u64 size)
1246 {
1247         u64 start_pfn = PFN_DOWN(start);
1248         u64 nr_pages = size >> PAGE_SHIFT;
1249
1250         /* Memory range must be aligned with section */
1251         if ((start_pfn & ~PAGE_SECTION_MASK) ||
1252             (nr_pages % PAGES_PER_SECTION) || (!nr_pages)) {
1253                 pr_err("Section-unaligned hotplug range: start 0x%llx, size 0x%llx\n",
1254                                 (unsigned long long)start,
1255                                 (unsigned long long)size);
1256                 return -EINVAL;
1257         }
1258
1259         return 0;
1260 }
1261
1262 /*
1263  * If movable zone has already been setup, newly added memory should be check.
1264  * If its address is higher than movable zone, it should be added as movable.
1265  * Without this check, movable zone may overlap with other zone.
1266  */
1267 static int should_add_memory_movable(int nid, u64 start, u64 size)
1268 {
1269         unsigned long start_pfn = start >> PAGE_SHIFT;
1270         pg_data_t *pgdat = NODE_DATA(nid);
1271         struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
1272
1273         if (zone_is_empty(movable_zone))
1274                 return 0;
1275
1276         if (movable_zone->zone_start_pfn <= start_pfn)
1277                 return 1;
1278
1279         return 0;
1280 }
1281
1282 int zone_for_memory(int nid, u64 start, u64 size, int zone_default,
1283                 bool for_device)
1284 {
1285 #ifdef CONFIG_ZONE_DEVICE
1286         if (for_device)
1287                 return ZONE_DEVICE;
1288 #endif
1289         if (should_add_memory_movable(nid, start, size))
1290                 return ZONE_MOVABLE;
1291
1292         return zone_default;
1293 }
1294
1295 static int online_memory_block(struct memory_block *mem, void *arg)
1296 {
1297         return memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
1298 }
1299
1300 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1301 int __ref add_memory_resource(int nid, struct resource *res, bool online)
1302 {
1303         u64 start, size;
1304         pg_data_t *pgdat = NULL;
1305         bool new_pgdat;
1306         bool new_node;
1307         int ret;
1308
1309         start = res->start;
1310         size = resource_size(res);
1311
1312         ret = check_hotplug_memory_range(start, size);
1313         if (ret)
1314                 return ret;
1315
1316         {       /* Stupid hack to suppress address-never-null warning */
1317                 void *p = NODE_DATA(nid);
1318                 new_pgdat = !p;
1319         }
1320
1321         mem_hotplug_begin();
1322
1323         /*
1324          * Add new range to memblock so that when hotadd_new_pgdat() is called
1325          * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1326          * this new range and calculate total pages correctly.  The range will
1327          * be removed at hot-remove time.
1328          */
1329         memblock_add_node(start, size, nid);
1330
1331         new_node = !node_online(nid);
1332         if (new_node) {
1333                 pgdat = hotadd_new_pgdat(nid, start);
1334                 ret = -ENOMEM;
1335                 if (!pgdat)
1336                         goto error;
1337         }
1338
1339         /* call arch's memory hotadd */
1340         ret = arch_add_memory(nid, start, size, false);
1341
1342         if (ret < 0)
1343                 goto error;
1344
1345         /* we online node here. we can't roll back from here. */
1346         node_set_online(nid);
1347
1348         if (new_node) {
1349                 ret = register_one_node(nid);
1350                 /*
1351                  * If sysfs file of new node can't create, cpu on the node
1352                  * can't be hot-added. There is no rollback way now.
1353                  * So, check by BUG_ON() to catch it reluctantly..
1354                  */
1355                 BUG_ON(ret);
1356         }
1357
1358         /* create new memmap entry */
1359         firmware_map_add_hotplug(start, start + size, "System RAM");
1360
1361         /* online pages if requested */
1362         if (online)
1363                 walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
1364                                   NULL, online_memory_block);
1365
1366         goto out;
1367
1368 error:
1369         /* rollback pgdat allocation and others */
1370         if (new_pgdat)
1371                 rollback_node_hotadd(nid, pgdat);
1372         memblock_remove(start, size);
1373
1374 out:
1375         mem_hotplug_done();
1376         return ret;
1377 }
1378 EXPORT_SYMBOL_GPL(add_memory_resource);
1379
1380 int __ref add_memory(int nid, u64 start, u64 size)
1381 {
1382         struct resource *res;
1383         int ret;
1384
1385         res = register_memory_resource(start, size);
1386         if (IS_ERR(res))
1387                 return PTR_ERR(res);
1388
1389         ret = add_memory_resource(nid, res, memhp_auto_online);
1390         if (ret < 0)
1391                 release_memory_resource(res);
1392         return ret;
1393 }
1394 EXPORT_SYMBOL_GPL(add_memory);
1395
1396 #ifdef CONFIG_MEMORY_HOTREMOVE
1397 /*
1398  * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1399  * set and the size of the free page is given by page_order(). Using this,
1400  * the function determines if the pageblock contains only free pages.
1401  * Due to buddy contraints, a free page at least the size of a pageblock will
1402  * be located at the start of the pageblock
1403  */
1404 static inline int pageblock_free(struct page *page)
1405 {
1406         return PageBuddy(page) && page_order(page) >= pageblock_order;
1407 }
1408
1409 /* Return the start of the next active pageblock after a given page */
1410 static struct page *next_active_pageblock(struct page *page)
1411 {
1412         /* Ensure the starting page is pageblock-aligned */
1413         BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1414
1415         /* If the entire pageblock is free, move to the end of free page */
1416         if (pageblock_free(page)) {
1417                 int order;
1418                 /* be careful. we don't have locks, page_order can be changed.*/
1419                 order = page_order(page);
1420                 if ((order < MAX_ORDER) && (order >= pageblock_order))
1421                         return page + (1 << order);
1422         }
1423
1424         return page + pageblock_nr_pages;
1425 }
1426
1427 /* Checks if this range of memory is likely to be hot-removable. */
1428 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1429 {
1430         struct page *page = pfn_to_page(start_pfn);
1431         struct page *end_page = page + nr_pages;
1432
1433         /* Check the starting page of each pageblock within the range */
1434         for (; page < end_page; page = next_active_pageblock(page)) {
1435                 if (!is_pageblock_removable_nolock(page))
1436                         return false;
1437                 cond_resched();
1438         }
1439
1440         /* All pageblocks in the memory block are likely to be hot-removable */
1441         return true;
1442 }
1443
1444 /*
1445  * Confirm all pages in a range [start, end) is belongs to the same zone.
1446  */
1447 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
1448 {
1449         unsigned long pfn, sec_end_pfn;
1450         struct zone *zone = NULL;
1451         struct page *page;
1452         int i;
1453         for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn);
1454              pfn < end_pfn;
1455              pfn = sec_end_pfn + 1, sec_end_pfn += PAGES_PER_SECTION) {
1456                 /* Make sure the memory section is present first */
1457                 if (!present_section_nr(pfn_to_section_nr(pfn)))
1458                         continue;
1459                 for (; pfn < sec_end_pfn && pfn < end_pfn;
1460                      pfn += MAX_ORDER_NR_PAGES) {
1461                         i = 0;
1462                         /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1463                         while ((i < MAX_ORDER_NR_PAGES) &&
1464                                 !pfn_valid_within(pfn + i))
1465                                 i++;
1466                         if (i == MAX_ORDER_NR_PAGES)
1467                                 continue;
1468                         page = pfn_to_page(pfn + i);
1469                         if (zone && page_zone(page) != zone)
1470                                 return 0;
1471                         zone = page_zone(page);
1472                 }
1473         }
1474         return 1;
1475 }
1476
1477 /*
1478  * Scan pfn range [start,end) to find movable/migratable pages (LRU pages
1479  * and hugepages). We scan pfn because it's much easier than scanning over
1480  * linked list. This function returns the pfn of the first found movable
1481  * page if it's found, otherwise 0.
1482  */
1483 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1484 {
1485         unsigned long pfn;
1486         struct page *page;
1487         for (pfn = start; pfn < end; pfn++) {
1488                 if (pfn_valid(pfn)) {
1489                         page = pfn_to_page(pfn);
1490                         if (PageLRU(page))
1491                                 return pfn;
1492                         if (PageHuge(page)) {
1493                                 if (page_huge_active(page))
1494                                         return pfn;
1495                                 else
1496                                         pfn = round_up(pfn + 1,
1497                                                 1 << compound_order(page)) - 1;
1498                         }
1499                 }
1500         }
1501         return 0;
1502 }
1503
1504 #define NR_OFFLINE_AT_ONCE_PAGES        (256)
1505 static int
1506 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1507 {
1508         unsigned long pfn;
1509         struct page *page;
1510         int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1511         int not_managed = 0;
1512         int ret = 0;
1513         LIST_HEAD(source);
1514
1515         for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1516                 if (!pfn_valid(pfn))
1517                         continue;
1518                 page = pfn_to_page(pfn);
1519
1520                 if (PageHuge(page)) {
1521                         struct page *head = compound_head(page);
1522                         pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1523                         if (compound_order(head) > PFN_SECTION_SHIFT) {
1524                                 ret = -EBUSY;
1525                                 break;
1526                         }
1527                         if (isolate_huge_page(page, &source))
1528                                 move_pages -= 1 << compound_order(head);
1529                         continue;
1530                 }
1531
1532                 if (!get_page_unless_zero(page))
1533                         continue;
1534                 /*
1535                  * We can skip free pages. And we can only deal with pages on
1536                  * LRU.
1537                  */
1538                 ret = isolate_lru_page(page);
1539                 if (!ret) { /* Success */
1540                         put_page(page);
1541                         list_add_tail(&page->lru, &source);
1542                         move_pages--;
1543                         inc_zone_page_state(page, NR_ISOLATED_ANON +
1544                                             page_is_file_cache(page));
1545
1546                 } else {
1547 #ifdef CONFIG_DEBUG_VM
1548                         pr_alert("removing pfn %lx from LRU failed\n", pfn);
1549                         dump_page(page, "failed to remove from LRU");
1550 #endif
1551                         put_page(page);
1552                         /* Because we don't have big zone->lock. we should
1553                            check this again here. */
1554                         if (page_count(page)) {
1555                                 not_managed++;
1556                                 ret = -EBUSY;
1557                                 break;
1558                         }
1559                 }
1560         }
1561         if (!list_empty(&source)) {
1562                 if (not_managed) {
1563                         putback_movable_pages(&source);
1564                         goto out;
1565                 }
1566
1567                 /*
1568                  * alloc_migrate_target should be improooooved!!
1569                  * migrate_pages returns # of failed pages.
1570                  */
1571                 ret = migrate_pages(&source, alloc_migrate_target, NULL, 0,
1572                                         MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1573                 if (ret)
1574                         putback_movable_pages(&source);
1575         }
1576 out:
1577         return ret;
1578 }
1579
1580 /*
1581  * remove from free_area[] and mark all as Reserved.
1582  */
1583 static int
1584 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1585                         void *data)
1586 {
1587         __offline_isolated_pages(start, start + nr_pages);
1588         return 0;
1589 }
1590
1591 static void
1592 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1593 {
1594         walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1595                                 offline_isolated_pages_cb);
1596 }
1597
1598 /*
1599  * Check all pages in range, recoreded as memory resource, are isolated.
1600  */
1601 static int
1602 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1603                         void *data)
1604 {
1605         int ret;
1606         long offlined = *(long *)data;
1607         ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1608         offlined = nr_pages;
1609         if (!ret)
1610                 *(long *)data += offlined;
1611         return ret;
1612 }
1613
1614 static long
1615 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1616 {
1617         long offlined = 0;
1618         int ret;
1619
1620         ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1621                         check_pages_isolated_cb);
1622         if (ret < 0)
1623                 offlined = (long)ret;
1624         return offlined;
1625 }
1626
1627 #ifdef CONFIG_MOVABLE_NODE
1628 /*
1629  * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1630  * normal memory.
1631  */
1632 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1633 {
1634         return true;
1635 }
1636 #else /* CONFIG_MOVABLE_NODE */
1637 /* ensure the node has NORMAL memory if it is still online */
1638 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1639 {
1640         struct pglist_data *pgdat = zone->zone_pgdat;
1641         unsigned long present_pages = 0;
1642         enum zone_type zt;
1643
1644         for (zt = 0; zt <= ZONE_NORMAL; zt++)
1645                 present_pages += pgdat->node_zones[zt].present_pages;
1646
1647         if (present_pages > nr_pages)
1648                 return true;
1649
1650         present_pages = 0;
1651         for (; zt <= ZONE_MOVABLE; zt++)
1652                 present_pages += pgdat->node_zones[zt].present_pages;
1653
1654         /*
1655          * we can't offline the last normal memory until all
1656          * higher memory is offlined.
1657          */
1658         return present_pages == 0;
1659 }
1660 #endif /* CONFIG_MOVABLE_NODE */
1661
1662 static int __init cmdline_parse_movable_node(char *p)
1663 {
1664 #ifdef CONFIG_MOVABLE_NODE
1665         /*
1666          * Memory used by the kernel cannot be hot-removed because Linux
1667          * cannot migrate the kernel pages. When memory hotplug is
1668          * enabled, we should prevent memblock from allocating memory
1669          * for the kernel.
1670          *
1671          * ACPI SRAT records all hotpluggable memory ranges. But before
1672          * SRAT is parsed, we don't know about it.
1673          *
1674          * The kernel image is loaded into memory at very early time. We
1675          * cannot prevent this anyway. So on NUMA system, we set any
1676          * node the kernel resides in as un-hotpluggable.
1677          *
1678          * Since on modern servers, one node could have double-digit
1679          * gigabytes memory, we can assume the memory around the kernel
1680          * image is also un-hotpluggable. So before SRAT is parsed, just
1681          * allocate memory near the kernel image to try the best to keep
1682          * the kernel away from hotpluggable memory.
1683          */
1684         memblock_set_bottom_up(true);
1685         movable_node_enabled = true;
1686 #else
1687         pr_warn("movable_node option not supported\n");
1688 #endif
1689         return 0;
1690 }
1691 early_param("movable_node", cmdline_parse_movable_node);
1692
1693 /* check which state of node_states will be changed when offline memory */
1694 static void node_states_check_changes_offline(unsigned long nr_pages,
1695                 struct zone *zone, struct memory_notify *arg)
1696 {
1697         struct pglist_data *pgdat = zone->zone_pgdat;
1698         unsigned long present_pages = 0;
1699         enum zone_type zt, zone_last = ZONE_NORMAL;
1700
1701         /*
1702          * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1703          * contains nodes which have zones of 0...ZONE_NORMAL,
1704          * set zone_last to ZONE_NORMAL.
1705          *
1706          * If we don't have HIGHMEM nor movable node,
1707          * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1708          * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1709          */
1710         if (N_MEMORY == N_NORMAL_MEMORY)
1711                 zone_last = ZONE_MOVABLE;
1712
1713         /*
1714          * check whether node_states[N_NORMAL_MEMORY] will be changed.
1715          * If the memory to be offline is in a zone of 0...zone_last,
1716          * and it is the last present memory, 0...zone_last will
1717          * become empty after offline , thus we can determind we will
1718          * need to clear the node from node_states[N_NORMAL_MEMORY].
1719          */
1720         for (zt = 0; zt <= zone_last; zt++)
1721                 present_pages += pgdat->node_zones[zt].present_pages;
1722         if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1723                 arg->status_change_nid_normal = zone_to_nid(zone);
1724         else
1725                 arg->status_change_nid_normal = -1;
1726
1727 #ifdef CONFIG_HIGHMEM
1728         /*
1729          * If we have movable node, node_states[N_HIGH_MEMORY]
1730          * contains nodes which have zones of 0...ZONE_HIGHMEM,
1731          * set zone_last to ZONE_HIGHMEM.
1732          *
1733          * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1734          * contains nodes which have zones of 0...ZONE_MOVABLE,
1735          * set zone_last to ZONE_MOVABLE.
1736          */
1737         zone_last = ZONE_HIGHMEM;
1738         if (N_MEMORY == N_HIGH_MEMORY)
1739                 zone_last = ZONE_MOVABLE;
1740
1741         for (; zt <= zone_last; zt++)
1742                 present_pages += pgdat->node_zones[zt].present_pages;
1743         if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1744                 arg->status_change_nid_high = zone_to_nid(zone);
1745         else
1746                 arg->status_change_nid_high = -1;
1747 #else
1748         arg->status_change_nid_high = arg->status_change_nid_normal;
1749 #endif
1750
1751         /*
1752          * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1753          */
1754         zone_last = ZONE_MOVABLE;
1755
1756         /*
1757          * check whether node_states[N_HIGH_MEMORY] will be changed
1758          * If we try to offline the last present @nr_pages from the node,
1759          * we can determind we will need to clear the node from
1760          * node_states[N_HIGH_MEMORY].
1761          */
1762         for (; zt <= zone_last; zt++)
1763                 present_pages += pgdat->node_zones[zt].present_pages;
1764         if (nr_pages >= present_pages)
1765                 arg->status_change_nid = zone_to_nid(zone);
1766         else
1767                 arg->status_change_nid = -1;
1768 }
1769
1770 static void node_states_clear_node(int node, struct memory_notify *arg)
1771 {
1772         if (arg->status_change_nid_normal >= 0)
1773                 node_clear_state(node, N_NORMAL_MEMORY);
1774
1775         if ((N_MEMORY != N_NORMAL_MEMORY) &&
1776             (arg->status_change_nid_high >= 0))
1777                 node_clear_state(node, N_HIGH_MEMORY);
1778
1779         if ((N_MEMORY != N_HIGH_MEMORY) &&
1780             (arg->status_change_nid >= 0))
1781                 node_clear_state(node, N_MEMORY);
1782 }
1783
1784 static int __ref __offline_pages(unsigned long start_pfn,
1785                   unsigned long end_pfn, unsigned long timeout)
1786 {
1787         unsigned long pfn, nr_pages, expire;
1788         long offlined_pages;
1789         int ret, drain, retry_max, node;
1790         unsigned long flags;
1791         struct zone *zone;
1792         struct memory_notify arg;
1793
1794         /* at least, alignment against pageblock is necessary */
1795         if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1796                 return -EINVAL;
1797         if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1798                 return -EINVAL;
1799         /* This makes hotplug much easier...and readable.
1800            we assume this for now. .*/
1801         if (!test_pages_in_a_zone(start_pfn, end_pfn))
1802                 return -EINVAL;
1803
1804         zone = page_zone(pfn_to_page(start_pfn));
1805         node = zone_to_nid(zone);
1806         nr_pages = end_pfn - start_pfn;
1807
1808         if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1809                 return -EINVAL;
1810
1811         /* set above range as isolated */
1812         ret = start_isolate_page_range(start_pfn, end_pfn,
1813                                        MIGRATE_MOVABLE, true);
1814         if (ret)
1815                 return ret;
1816
1817         arg.start_pfn = start_pfn;
1818         arg.nr_pages = nr_pages;
1819         node_states_check_changes_offline(nr_pages, zone, &arg);
1820
1821         ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1822         ret = notifier_to_errno(ret);
1823         if (ret)
1824                 goto failed_removal;
1825
1826         pfn = start_pfn;
1827         expire = jiffies + timeout;
1828         drain = 0;
1829         retry_max = 5;
1830 repeat:
1831         /* start memory hot removal */
1832         ret = -EAGAIN;
1833         if (time_after(jiffies, expire))
1834                 goto failed_removal;
1835         ret = -EINTR;
1836         if (signal_pending(current))
1837                 goto failed_removal;
1838         ret = 0;
1839         if (drain) {
1840                 lru_add_drain_all();
1841                 cond_resched();
1842                 drain_all_pages(zone);
1843         }
1844
1845         pfn = scan_movable_pages(start_pfn, end_pfn);
1846         if (pfn) { /* We have movable pages */
1847                 ret = do_migrate_range(pfn, end_pfn);
1848                 if (!ret) {
1849                         drain = 1;
1850                         goto repeat;
1851                 } else {
1852                         if (ret < 0)
1853                                 if (--retry_max == 0)
1854                                         goto failed_removal;
1855                         yield();
1856                         drain = 1;
1857                         goto repeat;
1858                 }
1859         }
1860         /* drain all zone's lru pagevec, this is asynchronous... */
1861         lru_add_drain_all();
1862         yield();
1863         /* drain pcp pages, this is synchronous. */
1864         drain_all_pages(zone);
1865         /*
1866          * dissolve free hugepages in the memory block before doing offlining
1867          * actually in order to make hugetlbfs's object counting consistent.
1868          */
1869         dissolve_free_huge_pages(start_pfn, end_pfn);
1870         /* check again */
1871         offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1872         if (offlined_pages < 0) {
1873                 ret = -EBUSY;
1874                 goto failed_removal;
1875         }
1876         pr_info("Offlined Pages %ld\n", offlined_pages);
1877         /* Ok, all of our target is isolated.
1878            We cannot do rollback at this point. */
1879         offline_isolated_pages(start_pfn, end_pfn);
1880         /* reset pagetype flags and makes migrate type to be MOVABLE */
1881         undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1882         /* removal success */
1883         adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1884         zone->present_pages -= offlined_pages;
1885
1886         pgdat_resize_lock(zone->zone_pgdat, &flags);
1887         zone->zone_pgdat->node_present_pages -= offlined_pages;
1888         pgdat_resize_unlock(zone->zone_pgdat, &flags);
1889
1890         init_per_zone_wmark_min();
1891
1892         if (!populated_zone(zone)) {
1893                 zone_pcp_reset(zone);
1894                 mutex_lock(&zonelists_mutex);
1895                 build_all_zonelists(NULL, NULL);
1896                 mutex_unlock(&zonelists_mutex);
1897         } else
1898                 zone_pcp_update(zone);
1899
1900         node_states_clear_node(node, &arg);
1901         if (arg.status_change_nid >= 0) {
1902                 kswapd_stop(node);
1903                 kcompactd_stop(node);
1904         }
1905
1906         vm_total_pages = nr_free_pagecache_pages();
1907         writeback_set_ratelimit();
1908
1909         memory_notify(MEM_OFFLINE, &arg);
1910         return 0;
1911
1912 failed_removal:
1913         pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n",
1914                  (unsigned long long) start_pfn << PAGE_SHIFT,
1915                  ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1916         memory_notify(MEM_CANCEL_OFFLINE, &arg);
1917         /* pushback to free area */
1918         undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1919         return ret;
1920 }
1921
1922 /* Must be protected by mem_hotplug_begin() */
1923 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1924 {
1925         return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1926 }
1927 #endif /* CONFIG_MEMORY_HOTREMOVE */
1928
1929 /**
1930  * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1931  * @start_pfn: start pfn of the memory range
1932  * @end_pfn: end pfn of the memory range
1933  * @arg: argument passed to func
1934  * @func: callback for each memory section walked
1935  *
1936  * This function walks through all present mem sections in range
1937  * [start_pfn, end_pfn) and call func on each mem section.
1938  *
1939  * Returns the return value of func.
1940  */
1941 int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1942                 void *arg, int (*func)(struct memory_block *, void *))
1943 {
1944         struct memory_block *mem = NULL;
1945         struct mem_section *section;
1946         unsigned long pfn, section_nr;
1947         int ret;
1948
1949         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1950                 section_nr = pfn_to_section_nr(pfn);
1951                 if (!present_section_nr(section_nr))
1952                         continue;
1953
1954                 section = __nr_to_section(section_nr);
1955                 /* same memblock? */
1956                 if (mem)
1957                         if ((section_nr >= mem->start_section_nr) &&
1958                             (section_nr <= mem->end_section_nr))
1959                                 continue;
1960
1961                 mem = find_memory_block_hinted(section, mem);
1962                 if (!mem)
1963                         continue;
1964
1965                 ret = func(mem, arg);
1966                 if (ret) {
1967                         kobject_put(&mem->dev.kobj);
1968                         return ret;
1969                 }
1970         }
1971
1972         if (mem)
1973                 kobject_put(&mem->dev.kobj);
1974
1975         return 0;
1976 }
1977
1978 #ifdef CONFIG_MEMORY_HOTREMOVE
1979 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1980 {
1981         int ret = !is_memblock_offlined(mem);
1982
1983         if (unlikely(ret)) {
1984                 phys_addr_t beginpa, endpa;
1985
1986                 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1987                 endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1988                 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1989                         &beginpa, &endpa);
1990         }
1991
1992         return ret;
1993 }
1994
1995 static int check_cpu_on_node(pg_data_t *pgdat)
1996 {
1997         int cpu;
1998
1999         for_each_present_cpu(cpu) {
2000                 if (cpu_to_node(cpu) == pgdat->node_id)
2001                         /*
2002                          * the cpu on this node isn't removed, and we can't
2003                          * offline this node.
2004                          */
2005                         return -EBUSY;
2006         }
2007
2008         return 0;
2009 }
2010
2011 static void unmap_cpu_on_node(pg_data_t *pgdat)
2012 {
2013 #ifdef CONFIG_ACPI_NUMA
2014         int cpu;
2015
2016         for_each_possible_cpu(cpu)
2017                 if (cpu_to_node(cpu) == pgdat->node_id)
2018                         numa_clear_node(cpu);
2019 #endif
2020 }
2021
2022 static int check_and_unmap_cpu_on_node(pg_data_t *pgdat)
2023 {
2024         int ret;
2025
2026         ret = check_cpu_on_node(pgdat);
2027         if (ret)
2028                 return ret;
2029
2030         /*
2031          * the node will be offlined when we come here, so we can clear
2032          * the cpu_to_node() now.
2033          */
2034
2035         unmap_cpu_on_node(pgdat);
2036         return 0;
2037 }
2038
2039 /**
2040  * try_offline_node
2041  *
2042  * Offline a node if all memory sections and cpus of the node are removed.
2043  *
2044  * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2045  * and online/offline operations before this call.
2046  */
2047 void try_offline_node(int nid)
2048 {
2049         pg_data_t *pgdat = NODE_DATA(nid);
2050         unsigned long start_pfn = pgdat->node_start_pfn;
2051         unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
2052         unsigned long pfn;
2053         int i;
2054
2055         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
2056                 unsigned long section_nr = pfn_to_section_nr(pfn);
2057
2058                 if (!present_section_nr(section_nr))
2059                         continue;
2060
2061                 if (pfn_to_nid(pfn) != nid)
2062                         continue;
2063
2064                 /*
2065                  * some memory sections of this node are not removed, and we
2066                  * can't offline node now.
2067                  */
2068                 return;
2069         }
2070
2071         if (check_and_unmap_cpu_on_node(pgdat))
2072                 return;
2073
2074         /*
2075          * all memory/cpu of this node are removed, we can offline this
2076          * node now.
2077          */
2078         node_set_offline(nid);
2079         unregister_one_node(nid);
2080
2081         /* free waittable in each zone */
2082         for (i = 0; i < MAX_NR_ZONES; i++) {
2083                 struct zone *zone = pgdat->node_zones + i;
2084
2085                 /*
2086                  * wait_table may be allocated from boot memory,
2087                  * here only free if it's allocated by vmalloc.
2088                  */
2089                 if (is_vmalloc_addr(zone->wait_table)) {
2090                         vfree(zone->wait_table);
2091                         zone->wait_table = NULL;
2092                 }
2093         }
2094 }
2095 EXPORT_SYMBOL(try_offline_node);
2096
2097 /**
2098  * remove_memory
2099  *
2100  * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2101  * and online/offline operations before this call, as required by
2102  * try_offline_node().
2103  */
2104 void __ref remove_memory(int nid, u64 start, u64 size)
2105 {
2106         int ret;
2107
2108         BUG_ON(check_hotplug_memory_range(start, size));
2109
2110         mem_hotplug_begin();
2111
2112         /*
2113          * All memory blocks must be offlined before removing memory.  Check
2114          * whether all memory blocks in question are offline and trigger a BUG()
2115          * if this is not the case.
2116          */
2117         ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
2118                                 check_memblock_offlined_cb);
2119         if (ret)
2120                 BUG();
2121
2122         /* remove memmap entry */
2123         firmware_map_remove(start, start + size, "System RAM");
2124         memblock_free(start, size);
2125         memblock_remove(start, size);
2126
2127         arch_remove_memory(start, size);
2128
2129         try_offline_node(nid);
2130
2131         mem_hotplug_done();
2132 }
2133 EXPORT_SYMBOL_GPL(remove_memory);
2134 #endif /* CONFIG_MEMORY_HOTREMOVE */