ARM: mmp: remove mach/gpio-pxa.h
[linux-3.10.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/highmem.h>
9 #include <linux/export.h>
10 #include <linux/spinlock.h>
11 #include <linux/vmalloc.h>
12 #include "internal.h"
13 #include <asm/dma.h>
14 #include <asm/pgalloc.h>
15 #include <asm/pgtable.h>
16
17 /*
18  * Permanent SPARSEMEM data:
19  *
20  * 1) mem_section       - memory sections, mem_map's for valid memory
21  */
22 #ifdef CONFIG_SPARSEMEM_EXTREME
23 struct mem_section *mem_section[NR_SECTION_ROOTS]
24         ____cacheline_internodealigned_in_smp;
25 #else
26 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
27         ____cacheline_internodealigned_in_smp;
28 #endif
29 EXPORT_SYMBOL(mem_section);
30
31 #ifdef NODE_NOT_IN_PAGE_FLAGS
32 /*
33  * If we did not store the node number in the page then we have to
34  * do a lookup in the section_to_node_table in order to find which
35  * node the page belongs to.
36  */
37 #if MAX_NUMNODES <= 256
38 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
39 #else
40 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
41 #endif
42
43 int page_to_nid(const struct page *page)
44 {
45         return section_to_node_table[page_to_section(page)];
46 }
47 EXPORT_SYMBOL(page_to_nid);
48
49 static void set_section_nid(unsigned long section_nr, int nid)
50 {
51         section_to_node_table[section_nr] = nid;
52 }
53 #else /* !NODE_NOT_IN_PAGE_FLAGS */
54 static inline void set_section_nid(unsigned long section_nr, int nid)
55 {
56 }
57 #endif
58
59 #ifdef CONFIG_SPARSEMEM_EXTREME
60 static struct mem_section noinline __init_refok *sparse_index_alloc(int nid)
61 {
62         struct mem_section *section = NULL;
63         unsigned long array_size = SECTIONS_PER_ROOT *
64                                    sizeof(struct mem_section);
65
66         if (slab_is_available()) {
67                 if (node_state(nid, N_HIGH_MEMORY))
68                         section = kmalloc_node(array_size, GFP_KERNEL, nid);
69                 else
70                         section = kmalloc(array_size, GFP_KERNEL);
71         } else
72                 section = alloc_bootmem_node(NODE_DATA(nid), array_size);
73
74         if (section)
75                 memset(section, 0, array_size);
76
77         return section;
78 }
79
80 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
81 {
82         static DEFINE_SPINLOCK(index_init_lock);
83         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
84         struct mem_section *section;
85         int ret = 0;
86
87         if (mem_section[root])
88                 return -EEXIST;
89
90         section = sparse_index_alloc(nid);
91         if (!section)
92                 return -ENOMEM;
93         /*
94          * This lock keeps two different sections from
95          * reallocating for the same index
96          */
97         spin_lock(&index_init_lock);
98
99         if (mem_section[root]) {
100                 ret = -EEXIST;
101                 goto out;
102         }
103
104         mem_section[root] = section;
105 out:
106         spin_unlock(&index_init_lock);
107         return ret;
108 }
109 #else /* !SPARSEMEM_EXTREME */
110 static inline int sparse_index_init(unsigned long section_nr, int nid)
111 {
112         return 0;
113 }
114 #endif
115
116 /*
117  * Although written for the SPARSEMEM_EXTREME case, this happens
118  * to also work for the flat array case because
119  * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
120  */
121 int __section_nr(struct mem_section* ms)
122 {
123         unsigned long root_nr;
124         struct mem_section* root;
125
126         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
127                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
128                 if (!root)
129                         continue;
130
131                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
132                      break;
133         }
134
135         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
136 }
137
138 /*
139  * During early boot, before section_mem_map is used for an actual
140  * mem_map, we use section_mem_map to store the section's NUMA
141  * node.  This keeps us from having to use another data structure.  The
142  * node information is cleared just before we store the real mem_map.
143  */
144 static inline unsigned long sparse_encode_early_nid(int nid)
145 {
146         return (nid << SECTION_NID_SHIFT);
147 }
148
149 static inline int sparse_early_nid(struct mem_section *section)
150 {
151         return (section->section_mem_map >> SECTION_NID_SHIFT);
152 }
153
154 /* Validate the physical addressing limitations of the model */
155 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
156                                                 unsigned long *end_pfn)
157 {
158         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
159
160         /*
161          * Sanity checks - do not allow an architecture to pass
162          * in larger pfns than the maximum scope of sparsemem:
163          */
164         if (*start_pfn > max_sparsemem_pfn) {
165                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
166                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
167                         *start_pfn, *end_pfn, max_sparsemem_pfn);
168                 WARN_ON_ONCE(1);
169                 *start_pfn = max_sparsemem_pfn;
170                 *end_pfn = max_sparsemem_pfn;
171         } else if (*end_pfn > max_sparsemem_pfn) {
172                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
173                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
174                         *start_pfn, *end_pfn, max_sparsemem_pfn);
175                 WARN_ON_ONCE(1);
176                 *end_pfn = max_sparsemem_pfn;
177         }
178 }
179
180 /* Record a memory area against a node. */
181 void __init memory_present(int nid, unsigned long start, unsigned long end)
182 {
183         unsigned long pfn;
184
185         start &= PAGE_SECTION_MASK;
186         mminit_validate_memmodel_limits(&start, &end);
187         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
188                 unsigned long section = pfn_to_section_nr(pfn);
189                 struct mem_section *ms;
190
191                 sparse_index_init(section, nid);
192                 set_section_nid(section, nid);
193
194                 ms = __nr_to_section(section);
195                 if (!ms->section_mem_map)
196                         ms->section_mem_map = sparse_encode_early_nid(nid) |
197                                                         SECTION_MARKED_PRESENT;
198         }
199 }
200
201 /*
202  * Only used by the i386 NUMA architecures, but relatively
203  * generic code.
204  */
205 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
206                                                      unsigned long end_pfn)
207 {
208         unsigned long pfn;
209         unsigned long nr_pages = 0;
210
211         mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
212         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
213                 if (nid != early_pfn_to_nid(pfn))
214                         continue;
215
216                 if (pfn_present(pfn))
217                         nr_pages += PAGES_PER_SECTION;
218         }
219
220         return nr_pages * sizeof(struct page);
221 }
222
223 /*
224  * Subtle, we encode the real pfn into the mem_map such that
225  * the identity pfn - section_mem_map will return the actual
226  * physical page frame number.
227  */
228 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
229 {
230         return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
231 }
232
233 /*
234  * Decode mem_map from the coded memmap
235  */
236 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
237 {
238         /* mask off the extra low bits of information */
239         coded_mem_map &= SECTION_MAP_MASK;
240         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
241 }
242
243 static int __meminit sparse_init_one_section(struct mem_section *ms,
244                 unsigned long pnum, struct page *mem_map,
245                 unsigned long *pageblock_bitmap)
246 {
247         if (!present_section(ms))
248                 return -EINVAL;
249
250         ms->section_mem_map &= ~SECTION_MAP_MASK;
251         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
252                                                         SECTION_HAS_MEM_MAP;
253         ms->pageblock_flags = pageblock_bitmap;
254
255         return 1;
256 }
257
258 unsigned long usemap_size(void)
259 {
260         unsigned long size_bytes;
261         size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
262         size_bytes = roundup(size_bytes, sizeof(unsigned long));
263         return size_bytes;
264 }
265
266 #ifdef CONFIG_MEMORY_HOTPLUG
267 static unsigned long *__kmalloc_section_usemap(void)
268 {
269         return kmalloc(usemap_size(), GFP_KERNEL);
270 }
271 #endif /* CONFIG_MEMORY_HOTPLUG */
272
273 #ifdef CONFIG_MEMORY_HOTREMOVE
274 static unsigned long * __init
275 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
276                                          unsigned long size)
277 {
278         pg_data_t *host_pgdat;
279         unsigned long goal;
280         /*
281          * A page may contain usemaps for other sections preventing the
282          * page being freed and making a section unremovable while
283          * other sections referencing the usemap retmain active. Similarly,
284          * a pgdat can prevent a section being removed. If section A
285          * contains a pgdat and section B contains the usemap, both
286          * sections become inter-dependent. This allocates usemaps
287          * from the same section as the pgdat where possible to avoid
288          * this problem.
289          */
290         goal = __pa(pgdat) & PAGE_SECTION_MASK;
291         host_pgdat = NODE_DATA(early_pfn_to_nid(goal >> PAGE_SHIFT));
292         return __alloc_bootmem_node_nopanic(host_pgdat, size,
293                                             SMP_CACHE_BYTES, goal);
294 }
295
296 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
297 {
298         unsigned long usemap_snr, pgdat_snr;
299         static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
300         static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
301         struct pglist_data *pgdat = NODE_DATA(nid);
302         int usemap_nid;
303
304         usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
305         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
306         if (usemap_snr == pgdat_snr)
307                 return;
308
309         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
310                 /* skip redundant message */
311                 return;
312
313         old_usemap_snr = usemap_snr;
314         old_pgdat_snr = pgdat_snr;
315
316         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
317         if (usemap_nid != nid) {
318                 printk(KERN_INFO
319                        "node %d must be removed before remove section %ld\n",
320                        nid, usemap_snr);
321                 return;
322         }
323         /*
324          * There is a circular dependency.
325          * Some platforms allow un-removable section because they will just
326          * gather other removable sections for dynamic partitioning.
327          * Just notify un-removable section's number here.
328          */
329         printk(KERN_INFO "Section %ld and %ld (node %d)", usemap_snr,
330                pgdat_snr, nid);
331         printk(KERN_CONT
332                " have a circular dependency on usemap and pgdat allocations\n");
333 }
334 #else
335 static unsigned long * __init
336 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
337                                          unsigned long size)
338 {
339         return alloc_bootmem_node_nopanic(pgdat, size);
340 }
341
342 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
343 {
344 }
345 #endif /* CONFIG_MEMORY_HOTREMOVE */
346
347 static void __init sparse_early_usemaps_alloc_node(unsigned long**usemap_map,
348                                  unsigned long pnum_begin,
349                                  unsigned long pnum_end,
350                                  unsigned long usemap_count, int nodeid)
351 {
352         void *usemap;
353         unsigned long pnum;
354         int size = usemap_size();
355
356         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
357                                                           size * usemap_count);
358         if (!usemap) {
359                 printk(KERN_WARNING "%s: allocation failed\n", __func__);
360                 return;
361         }
362
363         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
364                 if (!present_section_nr(pnum))
365                         continue;
366                 usemap_map[pnum] = usemap;
367                 usemap += size;
368                 check_usemap_section_nr(nodeid, usemap_map[pnum]);
369         }
370 }
371
372 #ifndef CONFIG_SPARSEMEM_VMEMMAP
373 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
374 {
375         struct page *map;
376         unsigned long size;
377
378         map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
379         if (map)
380                 return map;
381
382         size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
383         map = __alloc_bootmem_node_high(NODE_DATA(nid), size,
384                                          PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
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 = __alloc_bootmem_node_high(NODE_DATA(nodeid), size * map_count,
409                                          PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
410         if (map) {
411                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
412                         if (!present_section_nr(pnum))
413                                 continue;
414                         map_map[pnum] = map;
415                         map += size;
416                 }
417                 return;
418         }
419
420         /* fallback */
421         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
422                 struct mem_section *ms;
423
424                 if (!present_section_nr(pnum))
425                         continue;
426                 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
427                 if (map_map[pnum])
428                         continue;
429                 ms = __nr_to_section(pnum);
430                 printk(KERN_ERR "%s: sparsemem memory map backing failed "
431                         "some memory will not be available.\n", __func__);
432                 ms->section_mem_map = 0;
433         }
434 }
435 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
436
437 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
438 static void __init sparse_early_mem_maps_alloc_node(struct page **map_map,
439                                  unsigned long pnum_begin,
440                                  unsigned long pnum_end,
441                                  unsigned long map_count, int nodeid)
442 {
443         sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
444                                          map_count, nodeid);
445 }
446 #else
447 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
448 {
449         struct page *map;
450         struct mem_section *ms = __nr_to_section(pnum);
451         int nid = sparse_early_nid(ms);
452
453         map = sparse_mem_map_populate(pnum, nid);
454         if (map)
455                 return map;
456
457         printk(KERN_ERR "%s: sparsemem memory map backing failed "
458                         "some memory will not be available.\n", __func__);
459         ms->section_mem_map = 0;
460         return NULL;
461 }
462 #endif
463
464 void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
465 {
466 }
467
468 /*
469  * Allocate the accumulated non-linear sections, allocate a mem_map
470  * for each and record the physical to section mapping.
471  */
472 void __init sparse_init(void)
473 {
474         unsigned long pnum;
475         struct page *map;
476         unsigned long *usemap;
477         unsigned long **usemap_map;
478         int size;
479         int nodeid_begin = 0;
480         unsigned long pnum_begin = 0;
481         unsigned long usemap_count;
482 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
483         unsigned long map_count;
484         int size2;
485         struct page **map_map;
486 #endif
487
488         /*
489          * map is using big page (aka 2M in x86 64 bit)
490          * usemap is less one page (aka 24 bytes)
491          * so alloc 2M (with 2M align) and 24 bytes in turn will
492          * make next 2M slip to one more 2M later.
493          * then in big system, the memory will have a lot of holes...
494          * here try to allocate 2M pages continuously.
495          *
496          * powerpc need to call sparse_init_one_section right after each
497          * sparse_early_mem_map_alloc, so allocate usemap_map at first.
498          */
499         size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
500         usemap_map = alloc_bootmem(size);
501         if (!usemap_map)
502                 panic("can not allocate usemap_map\n");
503
504         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
505                 struct mem_section *ms;
506
507                 if (!present_section_nr(pnum))
508                         continue;
509                 ms = __nr_to_section(pnum);
510                 nodeid_begin = sparse_early_nid(ms);
511                 pnum_begin = pnum;
512                 break;
513         }
514         usemap_count = 1;
515         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
516                 struct mem_section *ms;
517                 int nodeid;
518
519                 if (!present_section_nr(pnum))
520                         continue;
521                 ms = __nr_to_section(pnum);
522                 nodeid = sparse_early_nid(ms);
523                 if (nodeid == nodeid_begin) {
524                         usemap_count++;
525                         continue;
526                 }
527                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
528                 sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, pnum,
529                                                  usemap_count, nodeid_begin);
530                 /* new start, update count etc*/
531                 nodeid_begin = nodeid;
532                 pnum_begin = pnum;
533                 usemap_count = 1;
534         }
535         /* ok, last chunk */
536         sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, NR_MEM_SECTIONS,
537                                          usemap_count, nodeid_begin);
538
539 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
540         size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
541         map_map = alloc_bootmem(size2);
542         if (!map_map)
543                 panic("can not allocate map_map\n");
544
545         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
546                 struct mem_section *ms;
547
548                 if (!present_section_nr(pnum))
549                         continue;
550                 ms = __nr_to_section(pnum);
551                 nodeid_begin = sparse_early_nid(ms);
552                 pnum_begin = pnum;
553                 break;
554         }
555         map_count = 1;
556         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
557                 struct mem_section *ms;
558                 int nodeid;
559
560                 if (!present_section_nr(pnum))
561                         continue;
562                 ms = __nr_to_section(pnum);
563                 nodeid = sparse_early_nid(ms);
564                 if (nodeid == nodeid_begin) {
565                         map_count++;
566                         continue;
567                 }
568                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
569                 sparse_early_mem_maps_alloc_node(map_map, pnum_begin, pnum,
570                                                  map_count, nodeid_begin);
571                 /* new start, update count etc*/
572                 nodeid_begin = nodeid;
573                 pnum_begin = pnum;
574                 map_count = 1;
575         }
576         /* ok, last chunk */
577         sparse_early_mem_maps_alloc_node(map_map, pnum_begin, NR_MEM_SECTIONS,
578                                          map_count, nodeid_begin);
579 #endif
580
581         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
582                 if (!present_section_nr(pnum))
583                         continue;
584
585                 usemap = usemap_map[pnum];
586                 if (!usemap)
587                         continue;
588
589 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
590                 map = map_map[pnum];
591 #else
592                 map = sparse_early_mem_map_alloc(pnum);
593 #endif
594                 if (!map)
595                         continue;
596
597                 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
598                                                                 usemap);
599         }
600
601         vmemmap_populate_print_last();
602
603 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
604         free_bootmem(__pa(map_map), size2);
605 #endif
606         free_bootmem(__pa(usemap_map), size);
607 }
608
609 #ifdef CONFIG_MEMORY_HOTPLUG
610 #ifdef CONFIG_SPARSEMEM_VMEMMAP
611 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
612                                                  unsigned long nr_pages)
613 {
614         /* This will make the necessary allocations eventually. */
615         return sparse_mem_map_populate(pnum, nid);
616 }
617 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
618 {
619         return; /* XXX: Not implemented yet */
620 }
621 static void free_map_bootmem(struct page *page, unsigned long nr_pages)
622 {
623 }
624 #else
625 static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
626 {
627         struct page *page, *ret;
628         unsigned long memmap_size = sizeof(struct page) * nr_pages;
629
630         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
631         if (page)
632                 goto got_map_page;
633
634         ret = vmalloc(memmap_size);
635         if (ret)
636                 goto got_map_ptr;
637
638         return NULL;
639 got_map_page:
640         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
641 got_map_ptr:
642         memset(ret, 0, memmap_size);
643
644         return ret;
645 }
646
647 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
648                                                   unsigned long nr_pages)
649 {
650         return __kmalloc_section_memmap(nr_pages);
651 }
652
653 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
654 {
655         if (is_vmalloc_addr(memmap))
656                 vfree(memmap);
657         else
658                 free_pages((unsigned long)memmap,
659                            get_order(sizeof(struct page) * nr_pages));
660 }
661
662 static void free_map_bootmem(struct page *page, unsigned long nr_pages)
663 {
664         unsigned long maps_section_nr, removing_section_nr, i;
665         unsigned long magic;
666
667         for (i = 0; i < nr_pages; i++, page++) {
668                 magic = (unsigned long) page->lru.next;
669
670                 BUG_ON(magic == NODE_INFO);
671
672                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
673                 removing_section_nr = page->private;
674
675                 /*
676                  * When this function is called, the removing section is
677                  * logical offlined state. This means all pages are isolated
678                  * from page allocator. If removing section's memmap is placed
679                  * on the same section, it must not be freed.
680                  * If it is freed, page allocator may allocate it which will
681                  * be removed physically soon.
682                  */
683                 if (maps_section_nr != removing_section_nr)
684                         put_page_bootmem(page);
685         }
686 }
687 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
688
689 static void free_section_usemap(struct page *memmap, unsigned long *usemap)
690 {
691         struct page *usemap_page;
692         unsigned long nr_pages;
693
694         if (!usemap)
695                 return;
696
697         usemap_page = virt_to_page(usemap);
698         /*
699          * Check to see if allocation came from hot-plug-add
700          */
701         if (PageSlab(usemap_page)) {
702                 kfree(usemap);
703                 if (memmap)
704                         __kfree_section_memmap(memmap, PAGES_PER_SECTION);
705                 return;
706         }
707
708         /*
709          * The usemap came from bootmem. This is packed with other usemaps
710          * on the section which has pgdat at boot time. Just keep it as is now.
711          */
712
713         if (memmap) {
714                 struct page *memmap_page;
715                 memmap_page = virt_to_page(memmap);
716
717                 nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
718                         >> PAGE_SHIFT;
719
720                 free_map_bootmem(memmap_page, nr_pages);
721         }
722 }
723
724 /*
725  * returns the number of sections whose mem_maps were properly
726  * set.  If this is <=0, then that means that the passed-in
727  * map was not consumed and must be freed.
728  */
729 int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
730                            int nr_pages)
731 {
732         unsigned long section_nr = pfn_to_section_nr(start_pfn);
733         struct pglist_data *pgdat = zone->zone_pgdat;
734         struct mem_section *ms;
735         struct page *memmap;
736         unsigned long *usemap;
737         unsigned long flags;
738         int ret;
739
740         /*
741          * no locking for this, because it does its own
742          * plus, it does a kmalloc
743          */
744         ret = sparse_index_init(section_nr, pgdat->node_id);
745         if (ret < 0 && ret != -EEXIST)
746                 return ret;
747         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, nr_pages);
748         if (!memmap)
749                 return -ENOMEM;
750         usemap = __kmalloc_section_usemap();
751         if (!usemap) {
752                 __kfree_section_memmap(memmap, nr_pages);
753                 return -ENOMEM;
754         }
755
756         pgdat_resize_lock(pgdat, &flags);
757
758         ms = __pfn_to_section(start_pfn);
759         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
760                 ret = -EEXIST;
761                 goto out;
762         }
763
764         ms->section_mem_map |= SECTION_MARKED_PRESENT;
765
766         ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
767
768 out:
769         pgdat_resize_unlock(pgdat, &flags);
770         if (ret <= 0) {
771                 kfree(usemap);
772                 __kfree_section_memmap(memmap, nr_pages);
773         }
774         return ret;
775 }
776
777 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
778 {
779         struct page *memmap = NULL;
780         unsigned long *usemap = NULL;
781
782         if (ms->section_mem_map) {
783                 usemap = ms->pageblock_flags;
784                 memmap = sparse_decode_mem_map(ms->section_mem_map,
785                                                 __section_nr(ms));
786                 ms->section_mem_map = 0;
787                 ms->pageblock_flags = NULL;
788         }
789
790         free_section_usemap(memmap, usemap);
791 }
792 #endif