wireless: only use alpha2 regulatory information from country IE
[linux-2.6.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/module.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(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 count)
277 {
278         unsigned long section_nr;
279
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         section_nr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
291         return alloc_bootmem_section(usemap_size() * count, section_nr);
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 count)
336 {
337         return NULL;
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(unsigned long**usemap_map,
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         int size = usemap_size();
353
354         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
355                                                                  usemap_count);
356         if (usemap) {
357                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
358                         if (!present_section_nr(pnum))
359                                 continue;
360                         usemap_map[pnum] = usemap;
361                         usemap += size;
362                 }
363                 return;
364         }
365
366         usemap = alloc_bootmem_node(NODE_DATA(nodeid), size * usemap_count);
367         if (usemap) {
368                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
369                         if (!present_section_nr(pnum))
370                                 continue;
371                         usemap_map[pnum] = usemap;
372                         usemap += size;
373                         check_usemap_section_nr(nodeid, usemap_map[pnum]);
374                 }
375                 return;
376         }
377
378         printk(KERN_WARNING "%s: allocation failed\n", __func__);
379 }
380
381 #ifndef CONFIG_SPARSEMEM_VMEMMAP
382 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
383 {
384         struct page *map;
385
386         map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
387         if (map)
388                 return map;
389
390         map = alloc_bootmem_pages_node(NODE_DATA(nid),
391                        PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION));
392         return map;
393 }
394 void __init sparse_mem_maps_populate_node(struct page **map_map,
395                                           unsigned long pnum_begin,
396                                           unsigned long pnum_end,
397                                           unsigned long map_count, int nodeid)
398 {
399         void *map;
400         unsigned long pnum;
401         unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
402
403         map = alloc_remap(nodeid, size * map_count);
404         if (map) {
405                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
406                         if (!present_section_nr(pnum))
407                                 continue;
408                         map_map[pnum] = map;
409                         map += size;
410                 }
411                 return;
412         }
413
414         size = PAGE_ALIGN(size);
415         map = alloc_bootmem_pages_node(NODE_DATA(nodeid), size * map_count);
416         if (map) {
417                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
418                         if (!present_section_nr(pnum))
419                                 continue;
420                         map_map[pnum] = map;
421                         map += size;
422                 }
423                 return;
424         }
425
426         /* fallback */
427         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
428                 struct mem_section *ms;
429
430                 if (!present_section_nr(pnum))
431                         continue;
432                 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
433                 if (map_map[pnum])
434                         continue;
435                 ms = __nr_to_section(pnum);
436                 printk(KERN_ERR "%s: sparsemem memory map backing failed "
437                         "some memory will not be available.\n", __func__);
438                 ms->section_mem_map = 0;
439         }
440 }
441 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
442
443 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
444 static void __init sparse_early_mem_maps_alloc_node(struct page **map_map,
445                                  unsigned long pnum_begin,
446                                  unsigned long pnum_end,
447                                  unsigned long map_count, int nodeid)
448 {
449         sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
450                                          map_count, nodeid);
451 }
452 #else
453 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
454 {
455         struct page *map;
456         struct mem_section *ms = __nr_to_section(pnum);
457         int nid = sparse_early_nid(ms);
458
459         map = sparse_mem_map_populate(pnum, nid);
460         if (map)
461                 return map;
462
463         printk(KERN_ERR "%s: sparsemem memory map backing failed "
464                         "some memory will not be available.\n", __func__);
465         ms->section_mem_map = 0;
466         return NULL;
467 }
468 #endif
469
470 void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
471 {
472 }
473
474 /*
475  * Allocate the accumulated non-linear sections, allocate a mem_map
476  * for each and record the physical to section mapping.
477  */
478 void __init sparse_init(void)
479 {
480         unsigned long pnum;
481         struct page *map;
482         unsigned long *usemap;
483         unsigned long **usemap_map;
484         int size;
485         int nodeid_begin = 0;
486         unsigned long pnum_begin = 0;
487         unsigned long usemap_count;
488 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
489         unsigned long map_count;
490         int size2;
491         struct page **map_map;
492 #endif
493
494         /*
495          * map is using big page (aka 2M in x86 64 bit)
496          * usemap is less one page (aka 24 bytes)
497          * so alloc 2M (with 2M align) and 24 bytes in turn will
498          * make next 2M slip to one more 2M later.
499          * then in big system, the memory will have a lot of holes...
500          * here try to allocate 2M pages continously.
501          *
502          * powerpc need to call sparse_init_one_section right after each
503          * sparse_early_mem_map_alloc, so allocate usemap_map at first.
504          */
505         size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
506         usemap_map = alloc_bootmem(size);
507         if (!usemap_map)
508                 panic("can not allocate usemap_map\n");
509
510         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
511                 struct mem_section *ms;
512
513                 if (!present_section_nr(pnum))
514                         continue;
515                 ms = __nr_to_section(pnum);
516                 nodeid_begin = sparse_early_nid(ms);
517                 pnum_begin = pnum;
518                 break;
519         }
520         usemap_count = 1;
521         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
522                 struct mem_section *ms;
523                 int nodeid;
524
525                 if (!present_section_nr(pnum))
526                         continue;
527                 ms = __nr_to_section(pnum);
528                 nodeid = sparse_early_nid(ms);
529                 if (nodeid == nodeid_begin) {
530                         usemap_count++;
531                         continue;
532                 }
533                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
534                 sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, pnum,
535                                                  usemap_count, nodeid_begin);
536                 /* new start, update count etc*/
537                 nodeid_begin = nodeid;
538                 pnum_begin = pnum;
539                 usemap_count = 1;
540         }
541         /* ok, last chunk */
542         sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, NR_MEM_SECTIONS,
543                                          usemap_count, nodeid_begin);
544
545 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
546         size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
547         map_map = alloc_bootmem(size2);
548         if (!map_map)
549                 panic("can not allocate map_map\n");
550
551         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
552                 struct mem_section *ms;
553
554                 if (!present_section_nr(pnum))
555                         continue;
556                 ms = __nr_to_section(pnum);
557                 nodeid_begin = sparse_early_nid(ms);
558                 pnum_begin = pnum;
559                 break;
560         }
561         map_count = 1;
562         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
563                 struct mem_section *ms;
564                 int nodeid;
565
566                 if (!present_section_nr(pnum))
567                         continue;
568                 ms = __nr_to_section(pnum);
569                 nodeid = sparse_early_nid(ms);
570                 if (nodeid == nodeid_begin) {
571                         map_count++;
572                         continue;
573                 }
574                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
575                 sparse_early_mem_maps_alloc_node(map_map, pnum_begin, pnum,
576                                                  map_count, nodeid_begin);
577                 /* new start, update count etc*/
578                 nodeid_begin = nodeid;
579                 pnum_begin = pnum;
580                 map_count = 1;
581         }
582         /* ok, last chunk */
583         sparse_early_mem_maps_alloc_node(map_map, pnum_begin, NR_MEM_SECTIONS,
584                                          map_count, nodeid_begin);
585 #endif
586
587         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
588                 if (!present_section_nr(pnum))
589                         continue;
590
591                 usemap = usemap_map[pnum];
592                 if (!usemap)
593                         continue;
594
595 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
596                 map = map_map[pnum];
597 #else
598                 map = sparse_early_mem_map_alloc(pnum);
599 #endif
600                 if (!map)
601                         continue;
602
603                 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
604                                                                 usemap);
605         }
606
607         vmemmap_populate_print_last();
608
609 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
610         free_bootmem(__pa(map_map), size2);
611 #endif
612         free_bootmem(__pa(usemap_map), size);
613 }
614
615 #ifdef CONFIG_MEMORY_HOTPLUG
616 #ifdef CONFIG_SPARSEMEM_VMEMMAP
617 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
618                                                  unsigned long nr_pages)
619 {
620         /* This will make the necessary allocations eventually. */
621         return sparse_mem_map_populate(pnum, nid);
622 }
623 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
624 {
625         return; /* XXX: Not implemented yet */
626 }
627 static void free_map_bootmem(struct page *page, unsigned long nr_pages)
628 {
629 }
630 #else
631 static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
632 {
633         struct page *page, *ret;
634         unsigned long memmap_size = sizeof(struct page) * nr_pages;
635
636         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
637         if (page)
638                 goto got_map_page;
639
640         ret = vmalloc(memmap_size);
641         if (ret)
642                 goto got_map_ptr;
643
644         return NULL;
645 got_map_page:
646         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
647 got_map_ptr:
648         memset(ret, 0, memmap_size);
649
650         return ret;
651 }
652
653 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
654                                                   unsigned long nr_pages)
655 {
656         return __kmalloc_section_memmap(nr_pages);
657 }
658
659 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
660 {
661         if (is_vmalloc_addr(memmap))
662                 vfree(memmap);
663         else
664                 free_pages((unsigned long)memmap,
665                            get_order(sizeof(struct page) * nr_pages));
666 }
667
668 static void free_map_bootmem(struct page *page, unsigned long nr_pages)
669 {
670         unsigned long maps_section_nr, removing_section_nr, i;
671         int magic;
672
673         for (i = 0; i < nr_pages; i++, page++) {
674                 magic = atomic_read(&page->_mapcount);
675
676                 BUG_ON(magic == NODE_INFO);
677
678                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
679                 removing_section_nr = page->private;
680
681                 /*
682                  * When this function is called, the removing section is
683                  * logical offlined state. This means all pages are isolated
684                  * from page allocator. If removing section's memmap is placed
685                  * on the same section, it must not be freed.
686                  * If it is freed, page allocator may allocate it which will
687                  * be removed physically soon.
688                  */
689                 if (maps_section_nr != removing_section_nr)
690                         put_page_bootmem(page);
691         }
692 }
693 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
694
695 static void free_section_usemap(struct page *memmap, unsigned long *usemap)
696 {
697         struct page *usemap_page;
698         unsigned long nr_pages;
699
700         if (!usemap)
701                 return;
702
703         usemap_page = virt_to_page(usemap);
704         /*
705          * Check to see if allocation came from hot-plug-add
706          */
707         if (PageSlab(usemap_page)) {
708                 kfree(usemap);
709                 if (memmap)
710                         __kfree_section_memmap(memmap, PAGES_PER_SECTION);
711                 return;
712         }
713
714         /*
715          * The usemap came from bootmem. This is packed with other usemaps
716          * on the section which has pgdat at boot time. Just keep it as is now.
717          */
718
719         if (memmap) {
720                 struct page *memmap_page;
721                 memmap_page = virt_to_page(memmap);
722
723                 nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
724                         >> PAGE_SHIFT;
725
726                 free_map_bootmem(memmap_page, nr_pages);
727         }
728 }
729
730 /*
731  * returns the number of sections whose mem_maps were properly
732  * set.  If this is <=0, then that means that the passed-in
733  * map was not consumed and must be freed.
734  */
735 int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
736                            int nr_pages)
737 {
738         unsigned long section_nr = pfn_to_section_nr(start_pfn);
739         struct pglist_data *pgdat = zone->zone_pgdat;
740         struct mem_section *ms;
741         struct page *memmap;
742         unsigned long *usemap;
743         unsigned long flags;
744         int ret;
745
746         /*
747          * no locking for this, because it does its own
748          * plus, it does a kmalloc
749          */
750         ret = sparse_index_init(section_nr, pgdat->node_id);
751         if (ret < 0 && ret != -EEXIST)
752                 return ret;
753         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, nr_pages);
754         if (!memmap)
755                 return -ENOMEM;
756         usemap = __kmalloc_section_usemap();
757         if (!usemap) {
758                 __kfree_section_memmap(memmap, nr_pages);
759                 return -ENOMEM;
760         }
761
762         pgdat_resize_lock(pgdat, &flags);
763
764         ms = __pfn_to_section(start_pfn);
765         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
766                 ret = -EEXIST;
767                 goto out;
768         }
769
770         ms->section_mem_map |= SECTION_MARKED_PRESENT;
771
772         ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
773
774 out:
775         pgdat_resize_unlock(pgdat, &flags);
776         if (ret <= 0) {
777                 kfree(usemap);
778                 __kfree_section_memmap(memmap, nr_pages);
779         }
780         return ret;
781 }
782
783 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
784 {
785         struct page *memmap = NULL;
786         unsigned long *usemap = NULL;
787
788         if (ms->section_mem_map) {
789                 usemap = ms->pageblock_flags;
790                 memmap = sparse_decode_mem_map(ms->section_mem_map,
791                                                 __section_nr(ms));
792                 ms->section_mem_map = 0;
793                 ms->pageblock_flags = NULL;
794         }
795
796         free_section_usemap(memmap, usemap);
797 }
798 #endif