Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[firefly-linux-kernel-4.4.55.git] / mm / sparse.c
1 /*
2  * sparse memory mappings.
3  */
4 #include <linux/mm.h>
5 #include <linux/slab.h>
6 #include <linux/mmzone.h>
7 #include <linux/bootmem.h>
8 #include <linux/compiler.h>
9 #include <linux/highmem.h>
10 #include <linux/export.h>
11 #include <linux/spinlock.h>
12 #include <linux/vmalloc.h>
13
14 #include "internal.h"
15 #include <asm/dma.h>
16 #include <asm/pgalloc.h>
17 #include <asm/pgtable.h>
18
19 /*
20  * Permanent SPARSEMEM data:
21  *
22  * 1) mem_section       - memory sections, mem_map's for valid memory
23  */
24 #ifdef CONFIG_SPARSEMEM_EXTREME
25 struct mem_section *mem_section[NR_SECTION_ROOTS]
26         ____cacheline_internodealigned_in_smp;
27 #else
28 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
29         ____cacheline_internodealigned_in_smp;
30 #endif
31 EXPORT_SYMBOL(mem_section);
32
33 #ifdef NODE_NOT_IN_PAGE_FLAGS
34 /*
35  * If we did not store the node number in the page then we have to
36  * do a lookup in the section_to_node_table in order to find which
37  * node the page belongs to.
38  */
39 #if MAX_NUMNODES <= 256
40 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
41 #else
42 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
43 #endif
44
45 int page_to_nid(const struct page *page)
46 {
47         return section_to_node_table[page_to_section(page)];
48 }
49 EXPORT_SYMBOL(page_to_nid);
50
51 static void set_section_nid(unsigned long section_nr, int nid)
52 {
53         section_to_node_table[section_nr] = nid;
54 }
55 #else /* !NODE_NOT_IN_PAGE_FLAGS */
56 static inline void set_section_nid(unsigned long section_nr, int nid)
57 {
58 }
59 #endif
60
61 #ifdef CONFIG_SPARSEMEM_EXTREME
62 static struct mem_section noinline __init_refok *sparse_index_alloc(int nid)
63 {
64         struct mem_section *section = NULL;
65         unsigned long array_size = SECTIONS_PER_ROOT *
66                                    sizeof(struct mem_section);
67
68         if (slab_is_available()) {
69                 if (node_state(nid, N_HIGH_MEMORY))
70                         section = kzalloc_node(array_size, GFP_KERNEL, nid);
71                 else
72                         section = kzalloc(array_size, GFP_KERNEL);
73         } else {
74                 section = memblock_virt_alloc_node(array_size, nid);
75         }
76
77         return section;
78 }
79
80 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
81 {
82         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
83         struct mem_section *section;
84
85         if (mem_section[root])
86                 return -EEXIST;
87
88         section = sparse_index_alloc(nid);
89         if (!section)
90                 return -ENOMEM;
91
92         mem_section[root] = section;
93
94         return 0;
95 }
96 #else /* !SPARSEMEM_EXTREME */
97 static inline int sparse_index_init(unsigned long section_nr, int nid)
98 {
99         return 0;
100 }
101 #endif
102
103 /*
104  * Although written for the SPARSEMEM_EXTREME case, this happens
105  * to also work for the flat array case because
106  * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
107  */
108 int __section_nr(struct mem_section* ms)
109 {
110         unsigned long root_nr;
111         struct mem_section* root;
112
113         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
114                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
115                 if (!root)
116                         continue;
117
118                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
119                      break;
120         }
121
122         VM_BUG_ON(root_nr == NR_SECTION_ROOTS);
123
124         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
125 }
126
127 /*
128  * During early boot, before section_mem_map is used for an actual
129  * mem_map, we use section_mem_map to store the section's NUMA
130  * node.  This keeps us from having to use another data structure.  The
131  * node information is cleared just before we store the real mem_map.
132  */
133 static inline unsigned long sparse_encode_early_nid(int nid)
134 {
135         return (nid << SECTION_NID_SHIFT);
136 }
137
138 static inline int sparse_early_nid(struct mem_section *section)
139 {
140         return (section->section_mem_map >> SECTION_NID_SHIFT);
141 }
142
143 /* Validate the physical addressing limitations of the model */
144 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
145                                                 unsigned long *end_pfn)
146 {
147         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
148
149         /*
150          * Sanity checks - do not allow an architecture to pass
151          * in larger pfns than the maximum scope of sparsemem:
152          */
153         if (*start_pfn > max_sparsemem_pfn) {
154                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
155                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
156                         *start_pfn, *end_pfn, max_sparsemem_pfn);
157                 WARN_ON_ONCE(1);
158                 *start_pfn = max_sparsemem_pfn;
159                 *end_pfn = max_sparsemem_pfn;
160         } else if (*end_pfn > max_sparsemem_pfn) {
161                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
162                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
163                         *start_pfn, *end_pfn, max_sparsemem_pfn);
164                 WARN_ON_ONCE(1);
165                 *end_pfn = max_sparsemem_pfn;
166         }
167 }
168
169 /* Record a memory area against a node. */
170 void __init memory_present(int nid, unsigned long start, unsigned long end)
171 {
172         unsigned long pfn;
173
174         start &= PAGE_SECTION_MASK;
175         mminit_validate_memmodel_limits(&start, &end);
176         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
177                 unsigned long section = pfn_to_section_nr(pfn);
178                 struct mem_section *ms;
179
180                 sparse_index_init(section, nid);
181                 set_section_nid(section, nid);
182
183                 ms = __nr_to_section(section);
184                 if (!ms->section_mem_map)
185                         ms->section_mem_map = sparse_encode_early_nid(nid) |
186                                                         SECTION_MARKED_PRESENT;
187         }
188 }
189
190 /*
191  * Only used by the i386 NUMA architecures, but relatively
192  * generic code.
193  */
194 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
195                                                      unsigned long end_pfn)
196 {
197         unsigned long pfn;
198         unsigned long nr_pages = 0;
199
200         mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
201         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
202                 if (nid != early_pfn_to_nid(pfn))
203                         continue;
204
205                 if (pfn_present(pfn))
206                         nr_pages += PAGES_PER_SECTION;
207         }
208
209         return nr_pages * sizeof(struct page);
210 }
211
212 /*
213  * Subtle, we encode the real pfn into the mem_map such that
214  * the identity pfn - section_mem_map will return the actual
215  * physical page frame number.
216  */
217 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
218 {
219         return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
220 }
221
222 /*
223  * Decode mem_map from the coded memmap
224  */
225 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
226 {
227         /* mask off the extra low bits of information */
228         coded_mem_map &= SECTION_MAP_MASK;
229         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
230 }
231
232 static int __meminit sparse_init_one_section(struct mem_section *ms,
233                 unsigned long pnum, struct page *mem_map,
234                 unsigned long *pageblock_bitmap)
235 {
236         if (!present_section(ms))
237                 return -EINVAL;
238
239         ms->section_mem_map &= ~SECTION_MAP_MASK;
240         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
241                                                         SECTION_HAS_MEM_MAP;
242         ms->pageblock_flags = pageblock_bitmap;
243
244         return 1;
245 }
246
247 unsigned long usemap_size(void)
248 {
249         unsigned long size_bytes;
250         size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
251         size_bytes = roundup(size_bytes, sizeof(unsigned long));
252         return size_bytes;
253 }
254
255 #ifdef CONFIG_MEMORY_HOTPLUG
256 static unsigned long *__kmalloc_section_usemap(void)
257 {
258         return kmalloc(usemap_size(), GFP_KERNEL);
259 }
260 #endif /* CONFIG_MEMORY_HOTPLUG */
261
262 #ifdef CONFIG_MEMORY_HOTREMOVE
263 static unsigned long * __init
264 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
265                                          unsigned long size)
266 {
267         unsigned long goal, limit;
268         unsigned long *p;
269         int nid;
270         /*
271          * A page may contain usemaps for other sections preventing the
272          * page being freed and making a section unremovable while
273          * other sections referencing the usemap remain active. Similarly,
274          * a pgdat can prevent a section being removed. If section A
275          * contains a pgdat and section B contains the usemap, both
276          * sections become inter-dependent. This allocates usemaps
277          * from the same section as the pgdat where possible to avoid
278          * this problem.
279          */
280         goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
281         limit = goal + (1UL << PA_SECTION_SHIFT);
282         nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
283 again:
284         p = memblock_virt_alloc_try_nid_nopanic(size,
285                                                 SMP_CACHE_BYTES, goal, limit,
286                                                 nid);
287         if (!p && limit) {
288                 limit = 0;
289                 goto again;
290         }
291         return p;
292 }
293
294 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
295 {
296         unsigned long usemap_snr, pgdat_snr;
297         static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
298         static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
299         struct pglist_data *pgdat = NODE_DATA(nid);
300         int usemap_nid;
301
302         usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
303         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
304         if (usemap_snr == pgdat_snr)
305                 return;
306
307         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
308                 /* skip redundant message */
309                 return;
310
311         old_usemap_snr = usemap_snr;
312         old_pgdat_snr = pgdat_snr;
313
314         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
315         if (usemap_nid != nid) {
316                 printk(KERN_INFO
317                        "node %d must be removed before remove section %ld\n",
318                        nid, usemap_snr);
319                 return;
320         }
321         /*
322          * There is a circular dependency.
323          * Some platforms allow un-removable section because they will just
324          * gather other removable sections for dynamic partitioning.
325          * Just notify un-removable section's number here.
326          */
327         printk(KERN_INFO "Section %ld and %ld (node %d)", usemap_snr,
328                pgdat_snr, nid);
329         printk(KERN_CONT
330                " have a circular dependency on usemap and pgdat allocations\n");
331 }
332 #else
333 static unsigned long * __init
334 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
335                                          unsigned long size)
336 {
337         return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
338 }
339
340 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
341 {
342 }
343 #endif /* CONFIG_MEMORY_HOTREMOVE */
344
345 static void __init sparse_early_usemaps_alloc_node(void *data,
346                                  unsigned long pnum_begin,
347                                  unsigned long pnum_end,
348                                  unsigned long usemap_count, int nodeid)
349 {
350         void *usemap;
351         unsigned long pnum;
352         unsigned long **usemap_map = (unsigned long **)data;
353         int size = usemap_size();
354
355         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
356                                                           size * usemap_count);
357         if (!usemap) {
358                 printk(KERN_WARNING "%s: allocation failed\n", __func__);
359                 return;
360         }
361
362         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
363                 if (!present_section_nr(pnum))
364                         continue;
365                 usemap_map[pnum] = usemap;
366                 usemap += size;
367                 check_usemap_section_nr(nodeid, usemap_map[pnum]);
368         }
369 }
370
371 #ifndef CONFIG_SPARSEMEM_VMEMMAP
372 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
373 {
374         struct page *map;
375         unsigned long size;
376
377         map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
378         if (map)
379                 return map;
380
381         size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
382         map = memblock_virt_alloc_try_nid(size,
383                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
384                                           BOOTMEM_ALLOC_ACCESSIBLE, nid);
385         return map;
386 }
387 void __init sparse_mem_maps_populate_node(struct page **map_map,
388                                           unsigned long pnum_begin,
389                                           unsigned long pnum_end,
390                                           unsigned long map_count, int nodeid)
391 {
392         void *map;
393         unsigned long pnum;
394         unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
395
396         map = alloc_remap(nodeid, size * map_count);
397         if (map) {
398                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
399                         if (!present_section_nr(pnum))
400                                 continue;
401                         map_map[pnum] = map;
402                         map += size;
403                 }
404                 return;
405         }
406
407         size = PAGE_ALIGN(size);
408         map = memblock_virt_alloc_try_nid(size * map_count,
409                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
410                                           BOOTMEM_ALLOC_ACCESSIBLE, nodeid);
411         if (map) {
412                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
413                         if (!present_section_nr(pnum))
414                                 continue;
415                         map_map[pnum] = map;
416                         map += size;
417                 }
418                 return;
419         }
420
421         /* fallback */
422         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
423                 struct mem_section *ms;
424
425                 if (!present_section_nr(pnum))
426                         continue;
427                 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
428                 if (map_map[pnum])
429                         continue;
430                 ms = __nr_to_section(pnum);
431                 printk(KERN_ERR "%s: sparsemem memory map backing failed "
432                         "some memory will not be available.\n", __func__);
433                 ms->section_mem_map = 0;
434         }
435 }
436 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
437
438 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
439 static void __init sparse_early_mem_maps_alloc_node(void *data,
440                                  unsigned long pnum_begin,
441                                  unsigned long pnum_end,
442                                  unsigned long map_count, int nodeid)
443 {
444         struct page **map_map = (struct page **)data;
445         sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
446                                          map_count, nodeid);
447 }
448 #else
449 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
450 {
451         struct page *map;
452         struct mem_section *ms = __nr_to_section(pnum);
453         int nid = sparse_early_nid(ms);
454
455         map = sparse_mem_map_populate(pnum, nid);
456         if (map)
457                 return map;
458
459         printk(KERN_ERR "%s: sparsemem memory map backing failed "
460                         "some memory will not be available.\n", __func__);
461         ms->section_mem_map = 0;
462         return NULL;
463 }
464 #endif
465
466 void __weak __meminit vmemmap_populate_print_last(void)
467 {
468 }
469
470 /**
471  *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
472  *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
473  */
474 static void __init alloc_usemap_and_memmap(void (*alloc_func)
475                                         (void *, unsigned long, unsigned long,
476                                         unsigned long, int), void *data)
477 {
478         unsigned long pnum;
479         unsigned long map_count;
480         int nodeid_begin = 0;
481         unsigned long pnum_begin = 0;
482
483         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
484                 struct mem_section *ms;
485
486                 if (!present_section_nr(pnum))
487                         continue;
488                 ms = __nr_to_section(pnum);
489                 nodeid_begin = sparse_early_nid(ms);
490                 pnum_begin = pnum;
491                 break;
492         }
493         map_count = 1;
494         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
495                 struct mem_section *ms;
496                 int nodeid;
497
498                 if (!present_section_nr(pnum))
499                         continue;
500                 ms = __nr_to_section(pnum);
501                 nodeid = sparse_early_nid(ms);
502                 if (nodeid == nodeid_begin) {
503                         map_count++;
504                         continue;
505                 }
506                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
507                 alloc_func(data, pnum_begin, pnum,
508                                                 map_count, nodeid_begin);
509                 /* new start, update count etc*/
510                 nodeid_begin = nodeid;
511                 pnum_begin = pnum;
512                 map_count = 1;
513         }
514         /* ok, last chunk */
515         alloc_func(data, pnum_begin, NR_MEM_SECTIONS,
516                                                 map_count, nodeid_begin);
517 }
518
519 /*
520  * Allocate the accumulated non-linear sections, allocate a mem_map
521  * for each and record the physical to section mapping.
522  */
523 void __init sparse_init(void)
524 {
525         unsigned long pnum;
526         struct page *map;
527         unsigned long *usemap;
528         unsigned long **usemap_map;
529         int size;
530 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
531         int size2;
532         struct page **map_map;
533 #endif
534
535         /* see include/linux/mmzone.h 'struct mem_section' definition */
536         BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
537
538         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
539         set_pageblock_order();
540
541         /*
542          * map is using big page (aka 2M in x86 64 bit)
543          * usemap is less one page (aka 24 bytes)
544          * so alloc 2M (with 2M align) and 24 bytes in turn will
545          * make next 2M slip to one more 2M later.
546          * then in big system, the memory will have a lot of holes...
547          * here try to allocate 2M pages continuously.
548          *
549          * powerpc need to call sparse_init_one_section right after each
550          * sparse_early_mem_map_alloc, so allocate usemap_map at first.
551          */
552         size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
553         usemap_map = memblock_virt_alloc(size, 0);
554         if (!usemap_map)
555                 panic("can not allocate usemap_map\n");
556         alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
557                                                         (void *)usemap_map);
558
559 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
560         size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
561         map_map = memblock_virt_alloc(size2, 0);
562         if (!map_map)
563                 panic("can not allocate map_map\n");
564         alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
565                                                         (void *)map_map);
566 #endif
567
568         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
569                 if (!present_section_nr(pnum))
570                         continue;
571
572                 usemap = usemap_map[pnum];
573                 if (!usemap)
574                         continue;
575
576 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
577                 map = map_map[pnum];
578 #else
579                 map = sparse_early_mem_map_alloc(pnum);
580 #endif
581                 if (!map)
582                         continue;
583
584                 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
585                                                                 usemap);
586         }
587
588         vmemmap_populate_print_last();
589
590 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
591         memblock_free_early(__pa(map_map), size2);
592 #endif
593         memblock_free_early(__pa(usemap_map), size);
594 }
595
596 #ifdef CONFIG_MEMORY_HOTPLUG
597 #ifdef CONFIG_SPARSEMEM_VMEMMAP
598 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
599 {
600         /* This will make the necessary allocations eventually. */
601         return sparse_mem_map_populate(pnum, nid);
602 }
603 static void __kfree_section_memmap(struct page *memmap)
604 {
605         unsigned long start = (unsigned long)memmap;
606         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
607
608         vmemmap_free(start, end);
609 }
610 #ifdef CONFIG_MEMORY_HOTREMOVE
611 static void free_map_bootmem(struct page *memmap)
612 {
613         unsigned long start = (unsigned long)memmap;
614         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
615
616         vmemmap_free(start, end);
617 }
618 #endif /* CONFIG_MEMORY_HOTREMOVE */
619 #else
620 static struct page *__kmalloc_section_memmap(void)
621 {
622         struct page *page, *ret;
623         unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
624
625         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
626         if (page)
627                 goto got_map_page;
628
629         ret = vmalloc(memmap_size);
630         if (ret)
631                 goto got_map_ptr;
632
633         return NULL;
634 got_map_page:
635         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
636 got_map_ptr:
637
638         return ret;
639 }
640
641 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
642 {
643         return __kmalloc_section_memmap();
644 }
645
646 static void __kfree_section_memmap(struct page *memmap)
647 {
648         if (is_vmalloc_addr(memmap))
649                 vfree(memmap);
650         else
651                 free_pages((unsigned long)memmap,
652                            get_order(sizeof(struct page) * PAGES_PER_SECTION));
653 }
654
655 #ifdef CONFIG_MEMORY_HOTREMOVE
656 static void free_map_bootmem(struct page *memmap)
657 {
658         unsigned long maps_section_nr, removing_section_nr, i;
659         unsigned long magic, nr_pages;
660         struct page *page = virt_to_page(memmap);
661
662         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
663                 >> PAGE_SHIFT;
664
665         for (i = 0; i < nr_pages; i++, page++) {
666                 magic = (unsigned long) page->lru.next;
667
668                 BUG_ON(magic == NODE_INFO);
669
670                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
671                 removing_section_nr = page->private;
672
673                 /*
674                  * When this function is called, the removing section is
675                  * logical offlined state. This means all pages are isolated
676                  * from page allocator. If removing section's memmap is placed
677                  * on the same section, it must not be freed.
678                  * If it is freed, page allocator may allocate it which will
679                  * be removed physically soon.
680                  */
681                 if (maps_section_nr != removing_section_nr)
682                         put_page_bootmem(page);
683         }
684 }
685 #endif /* CONFIG_MEMORY_HOTREMOVE */
686 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
687
688 /*
689  * returns the number of sections whose mem_maps were properly
690  * set.  If this is <=0, then that means that the passed-in
691  * map was not consumed and must be freed.
692  */
693 int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
694 {
695         unsigned long section_nr = pfn_to_section_nr(start_pfn);
696         struct pglist_data *pgdat = zone->zone_pgdat;
697         struct mem_section *ms;
698         struct page *memmap;
699         unsigned long *usemap;
700         unsigned long flags;
701         int ret;
702
703         /*
704          * no locking for this, because it does its own
705          * plus, it does a kmalloc
706          */
707         ret = sparse_index_init(section_nr, pgdat->node_id);
708         if (ret < 0 && ret != -EEXIST)
709                 return ret;
710         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id);
711         if (!memmap)
712                 return -ENOMEM;
713         usemap = __kmalloc_section_usemap();
714         if (!usemap) {
715                 __kfree_section_memmap(memmap);
716                 return -ENOMEM;
717         }
718
719         pgdat_resize_lock(pgdat, &flags);
720
721         ms = __pfn_to_section(start_pfn);
722         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
723                 ret = -EEXIST;
724                 goto out;
725         }
726
727         memset(memmap, 0, sizeof(struct page) * PAGES_PER_SECTION);
728
729         ms->section_mem_map |= SECTION_MARKED_PRESENT;
730
731         ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
732
733 out:
734         pgdat_resize_unlock(pgdat, &flags);
735         if (ret <= 0) {
736                 kfree(usemap);
737                 __kfree_section_memmap(memmap);
738         }
739         return ret;
740 }
741
742 #ifdef CONFIG_MEMORY_HOTREMOVE
743 #ifdef CONFIG_MEMORY_FAILURE
744 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
745 {
746         int i;
747
748         if (!memmap)
749                 return;
750
751         for (i = 0; i < PAGES_PER_SECTION; i++) {
752                 if (PageHWPoison(&memmap[i])) {
753                         atomic_long_sub(1, &num_poisoned_pages);
754                         ClearPageHWPoison(&memmap[i]);
755                 }
756         }
757 }
758 #else
759 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
760 {
761 }
762 #endif
763
764 static void free_section_usemap(struct page *memmap, unsigned long *usemap)
765 {
766         struct page *usemap_page;
767
768         if (!usemap)
769                 return;
770
771         usemap_page = virt_to_page(usemap);
772         /*
773          * Check to see if allocation came from hot-plug-add
774          */
775         if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
776                 kfree(usemap);
777                 if (memmap)
778                         __kfree_section_memmap(memmap);
779                 return;
780         }
781
782         /*
783          * The usemap came from bootmem. This is packed with other usemaps
784          * on the section which has pgdat at boot time. Just keep it as is now.
785          */
786
787         if (memmap)
788                 free_map_bootmem(memmap);
789 }
790
791 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
792 {
793         struct page *memmap = NULL;
794         unsigned long *usemap = NULL, flags;
795         struct pglist_data *pgdat = zone->zone_pgdat;
796
797         pgdat_resize_lock(pgdat, &flags);
798         if (ms->section_mem_map) {
799                 usemap = ms->pageblock_flags;
800                 memmap = sparse_decode_mem_map(ms->section_mem_map,
801                                                 __section_nr(ms));
802                 ms->section_mem_map = 0;
803                 ms->pageblock_flags = NULL;
804         }
805         pgdat_resize_unlock(pgdat, &flags);
806
807         clear_hwpoisoned_pages(memmap, PAGES_PER_SECTION);
808         free_section_usemap(memmap, usemap);
809 }
810 #endif /* CONFIG_MEMORY_HOTREMOVE */
811 #endif /* CONFIG_MEMORY_HOTPLUG */