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TOMOYO Linux Cross Reference
Linux/mm/vmalloc.c

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  1 /*
  2  *  linux/mm/vmalloc.c
  3  *
  4  *  Copyright (C) 1993  Linus Torvalds
  5  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
  6  *  SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
  7  *  Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
  8  *  Numa awareness, Christoph Lameter, SGI, June 2005
  9  */
 10 
 11 #include <linux/vmalloc.h>
 12 #include <linux/mm.h>
 13 #include <linux/module.h>
 14 #include <linux/highmem.h>
 15 #include <linux/sched.h>
 16 #include <linux/slab.h>
 17 #include <linux/spinlock.h>
 18 #include <linux/interrupt.h>
 19 #include <linux/proc_fs.h>
 20 #include <linux/seq_file.h>
 21 #include <linux/debugobjects.h>
 22 #include <linux/kallsyms.h>
 23 #include <linux/list.h>
 24 #include <linux/rbtree.h>
 25 #include <linux/radix-tree.h>
 26 #include <linux/rcupdate.h>
 27 #include <linux/pfn.h>
 28 #include <linux/kmemleak.h>
 29 #include <linux/atomic.h>
 30 #include <linux/compiler.h>
 31 #include <linux/llist.h>
 32 #include <linux/bitops.h>
 33 
 34 #include <asm/uaccess.h>
 35 #include <asm/tlbflush.h>
 36 #include <asm/shmparam.h>
 37 
 38 #include "internal.h"
 39 
 40 struct vfree_deferred {
 41         struct llist_head list;
 42         struct work_struct wq;
 43 };
 44 static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
 45 
 46 static void __vunmap(const void *, int);
 47 
 48 static void free_work(struct work_struct *w)
 49 {
 50         struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
 51         struct llist_node *llnode = llist_del_all(&p->list);
 52         while (llnode) {
 53                 void *p = llnode;
 54                 llnode = llist_next(llnode);
 55                 __vunmap(p, 1);
 56         }
 57 }
 58 
 59 /*** Page table manipulation functions ***/
 60 
 61 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
 62 {
 63         pte_t *pte;
 64 
 65         pte = pte_offset_kernel(pmd, addr);
 66         do {
 67                 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
 68                 WARN_ON(!pte_none(ptent) && !pte_present(ptent));
 69         } while (pte++, addr += PAGE_SIZE, addr != end);
 70 }
 71 
 72 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
 73 {
 74         pmd_t *pmd;
 75         unsigned long next;
 76 
 77         pmd = pmd_offset(pud, addr);
 78         do {
 79                 next = pmd_addr_end(addr, end);
 80                 if (pmd_clear_huge(pmd))
 81                         continue;
 82                 if (pmd_none_or_clear_bad(pmd))
 83                         continue;
 84                 vunmap_pte_range(pmd, addr, next);
 85         } while (pmd++, addr = next, addr != end);
 86 }
 87 
 88 static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
 89 {
 90         pud_t *pud;
 91         unsigned long next;
 92 
 93         pud = pud_offset(pgd, addr);
 94         do {
 95                 next = pud_addr_end(addr, end);
 96                 if (pud_clear_huge(pud))
 97                         continue;
 98                 if (pud_none_or_clear_bad(pud))
 99                         continue;
100                 vunmap_pmd_range(pud, addr, next);
101         } while (pud++, addr = next, addr != end);
102 }
103 
104 static void vunmap_page_range(unsigned long addr, unsigned long end)
105 {
106         pgd_t *pgd;
107         unsigned long next;
108 
109         BUG_ON(addr >= end);
110         pgd = pgd_offset_k(addr);
111         do {
112                 next = pgd_addr_end(addr, end);
113                 if (pgd_none_or_clear_bad(pgd))
114                         continue;
115                 vunmap_pud_range(pgd, addr, next);
116         } while (pgd++, addr = next, addr != end);
117 }
118 
119 static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
120                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
121 {
122         pte_t *pte;
123 
124         /*
125          * nr is a running index into the array which helps higher level
126          * callers keep track of where we're up to.
127          */
128 
129         pte = pte_alloc_kernel(pmd, addr);
130         if (!pte)
131                 return -ENOMEM;
132         do {
133                 struct page *page = pages[*nr];
134 
135                 if (WARN_ON(!pte_none(*pte)))
136                         return -EBUSY;
137                 if (WARN_ON(!page))
138                         return -ENOMEM;
139                 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
140                 (*nr)++;
141         } while (pte++, addr += PAGE_SIZE, addr != end);
142         return 0;
143 }
144 
145 static int vmap_pmd_range(pud_t *pud, unsigned long addr,
146                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
147 {
148         pmd_t *pmd;
149         unsigned long next;
150 
151         pmd = pmd_alloc(&init_mm, pud, addr);
152         if (!pmd)
153                 return -ENOMEM;
154         do {
155                 next = pmd_addr_end(addr, end);
156                 if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
157                         return -ENOMEM;
158         } while (pmd++, addr = next, addr != end);
159         return 0;
160 }
161 
162 static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
163                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
164 {
165         pud_t *pud;
166         unsigned long next;
167 
168         pud = pud_alloc(&init_mm, pgd, addr);
169         if (!pud)
170                 return -ENOMEM;
171         do {
172                 next = pud_addr_end(addr, end);
173                 if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
174                         return -ENOMEM;
175         } while (pud++, addr = next, addr != end);
176         return 0;
177 }
178 
179 /*
180  * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
181  * will have pfns corresponding to the "pages" array.
182  *
183  * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
184  */
185 static int vmap_page_range_noflush(unsigned long start, unsigned long end,
186                                    pgprot_t prot, struct page **pages)
187 {
188         pgd_t *pgd;
189         unsigned long next;
190         unsigned long addr = start;
191         int err = 0;
192         int nr = 0;
193 
194         BUG_ON(addr >= end);
195         pgd = pgd_offset_k(addr);
196         do {
197                 next = pgd_addr_end(addr, end);
198                 err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
199                 if (err)
200                         return err;
201         } while (pgd++, addr = next, addr != end);
202 
203         return nr;
204 }
205 
206 static int vmap_page_range(unsigned long start, unsigned long end,
207                            pgprot_t prot, struct page **pages)
208 {
209         int ret;
210 
211         ret = vmap_page_range_noflush(start, end, prot, pages);
212         flush_cache_vmap(start, end);
213         return ret;
214 }
215 
216 int is_vmalloc_or_module_addr(const void *x)
217 {
218         /*
219          * ARM, x86-64 and sparc64 put modules in a special place,
220          * and fall back on vmalloc() if that fails. Others
221          * just put it in the vmalloc space.
222          */
223 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
224         unsigned long addr = (unsigned long)x;
225         if (addr >= MODULES_VADDR && addr < MODULES_END)
226                 return 1;
227 #endif
228         return is_vmalloc_addr(x);
229 }
230 
231 /*
232  * Walk a vmap address to the struct page it maps.
233  */
234 struct page *vmalloc_to_page(const void *vmalloc_addr)
235 {
236         unsigned long addr = (unsigned long) vmalloc_addr;
237         struct page *page = NULL;
238         pgd_t *pgd = pgd_offset_k(addr);
239 
240         /*
241          * XXX we might need to change this if we add VIRTUAL_BUG_ON for
242          * architectures that do not vmalloc module space
243          */
244         VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
245 
246         if (!pgd_none(*pgd)) {
247                 pud_t *pud = pud_offset(pgd, addr);
248                 if (!pud_none(*pud)) {
249                         pmd_t *pmd = pmd_offset(pud, addr);
250                         if (!pmd_none(*pmd)) {
251                                 pte_t *ptep, pte;
252 
253                                 ptep = pte_offset_map(pmd, addr);
254                                 pte = *ptep;
255                                 if (pte_present(pte))
256                                         page = pte_page(pte);
257                                 pte_unmap(ptep);
258                         }
259                 }
260         }
261         return page;
262 }
263 EXPORT_SYMBOL(vmalloc_to_page);
264 
265 /*
266  * Map a vmalloc()-space virtual address to the physical page frame number.
267  */
268 unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
269 {
270         return page_to_pfn(vmalloc_to_page(vmalloc_addr));
271 }
272 EXPORT_SYMBOL(vmalloc_to_pfn);
273 
274 
275 /*** Global kva allocator ***/
276 
277 #define VM_LAZY_FREE    0x01
278 #define VM_LAZY_FREEING 0x02
279 #define VM_VM_AREA      0x04
280 
281 static DEFINE_SPINLOCK(vmap_area_lock);
282 /* Export for kexec only */
283 LIST_HEAD(vmap_area_list);
284 static struct rb_root vmap_area_root = RB_ROOT;
285 
286 /* The vmap cache globals are protected by vmap_area_lock */
287 static struct rb_node *free_vmap_cache;
288 static unsigned long cached_hole_size;
289 static unsigned long cached_vstart;
290 static unsigned long cached_align;
291 
292 static unsigned long vmap_area_pcpu_hole;
293 
294 static struct vmap_area *__find_vmap_area(unsigned long addr)
295 {
296         struct rb_node *n = vmap_area_root.rb_node;
297 
298         while (n) {
299                 struct vmap_area *va;
300 
301                 va = rb_entry(n, struct vmap_area, rb_node);
302                 if (addr < va->va_start)
303                         n = n->rb_left;
304                 else if (addr >= va->va_end)
305                         n = n->rb_right;
306                 else
307                         return va;
308         }
309 
310         return NULL;
311 }
312 
313 static void __insert_vmap_area(struct vmap_area *va)
314 {
315         struct rb_node **p = &vmap_area_root.rb_node;
316         struct rb_node *parent = NULL;
317         struct rb_node *tmp;
318 
319         while (*p) {
320                 struct vmap_area *tmp_va;
321 
322                 parent = *p;
323                 tmp_va = rb_entry(parent, struct vmap_area, rb_node);
324                 if (va->va_start < tmp_va->va_end)
325                         p = &(*p)->rb_left;
326                 else if (va->va_end > tmp_va->va_start)
327                         p = &(*p)->rb_right;
328                 else
329                         BUG();
330         }
331 
332         rb_link_node(&va->rb_node, parent, p);
333         rb_insert_color(&va->rb_node, &vmap_area_root);
334 
335         /* address-sort this list */
336         tmp = rb_prev(&va->rb_node);
337         if (tmp) {
338                 struct vmap_area *prev;
339                 prev = rb_entry(tmp, struct vmap_area, rb_node);
340                 list_add_rcu(&va->list, &prev->list);
341         } else
342                 list_add_rcu(&va->list, &vmap_area_list);
343 }
344 
345 static void purge_vmap_area_lazy(void);
346 
347 /*
348  * Allocate a region of KVA of the specified size and alignment, within the
349  * vstart and vend.
350  */
351 static struct vmap_area *alloc_vmap_area(unsigned long size,
352                                 unsigned long align,
353                                 unsigned long vstart, unsigned long vend,
354                                 int node, gfp_t gfp_mask)
355 {
356         struct vmap_area *va;
357         struct rb_node *n;
358         unsigned long addr;
359         int purged = 0;
360         struct vmap_area *first;
361 
362         BUG_ON(!size);
363         BUG_ON(offset_in_page(size));
364         BUG_ON(!is_power_of_2(align));
365 
366         va = kmalloc_node(sizeof(struct vmap_area),
367                         gfp_mask & GFP_RECLAIM_MASK, node);
368         if (unlikely(!va))
369                 return ERR_PTR(-ENOMEM);
370 
371         /*
372          * Only scan the relevant parts containing pointers to other objects
373          * to avoid false negatives.
374          */
375         kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK);
376 
377 retry:
378         spin_lock(&vmap_area_lock);
379         /*
380          * Invalidate cache if we have more permissive parameters.
381          * cached_hole_size notes the largest hole noticed _below_
382          * the vmap_area cached in free_vmap_cache: if size fits
383          * into that hole, we want to scan from vstart to reuse
384          * the hole instead of allocating above free_vmap_cache.
385          * Note that __free_vmap_area may update free_vmap_cache
386          * without updating cached_hole_size or cached_align.
387          */
388         if (!free_vmap_cache ||
389                         size < cached_hole_size ||
390                         vstart < cached_vstart ||
391                         align < cached_align) {
392 nocache:
393                 cached_hole_size = 0;
394                 free_vmap_cache = NULL;
395         }
396         /* record if we encounter less permissive parameters */
397         cached_vstart = vstart;
398         cached_align = align;
399 
400         /* find starting point for our search */
401         if (free_vmap_cache) {
402                 first = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
403                 addr = ALIGN(first->va_end, align);
404                 if (addr < vstart)
405                         goto nocache;
406                 if (addr + size < addr)
407                         goto overflow;
408 
409         } else {
410                 addr = ALIGN(vstart, align);
411                 if (addr + size < addr)
412                         goto overflow;
413 
414                 n = vmap_area_root.rb_node;
415                 first = NULL;
416 
417                 while (n) {
418                         struct vmap_area *tmp;
419                         tmp = rb_entry(n, struct vmap_area, rb_node);
420                         if (tmp->va_end >= addr) {
421                                 first = tmp;
422                                 if (tmp->va_start <= addr)
423                                         break;
424                                 n = n->rb_left;
425                         } else
426                                 n = n->rb_right;
427                 }
428 
429                 if (!first)
430                         goto found;
431         }
432 
433         /* from the starting point, walk areas until a suitable hole is found */
434         while (addr + size > first->va_start && addr + size <= vend) {
435                 if (addr + cached_hole_size < first->va_start)
436                         cached_hole_size = first->va_start - addr;
437                 addr = ALIGN(first->va_end, align);
438                 if (addr + size < addr)
439                         goto overflow;
440 
441                 if (list_is_last(&first->list, &vmap_area_list))
442                         goto found;
443 
444                 first = list_next_entry(first, list);
445         }
446 
447 found:
448         if (addr + size > vend)
449                 goto overflow;
450 
451         va->va_start = addr;
452         va->va_end = addr + size;
453         va->flags = 0;
454         __insert_vmap_area(va);
455         free_vmap_cache = &va->rb_node;
456         spin_unlock(&vmap_area_lock);
457 
458         BUG_ON(!IS_ALIGNED(va->va_start, align));
459         BUG_ON(va->va_start < vstart);
460         BUG_ON(va->va_end > vend);
461 
462         return va;
463 
464 overflow:
465         spin_unlock(&vmap_area_lock);
466         if (!purged) {
467                 purge_vmap_area_lazy();
468                 purged = 1;
469                 goto retry;
470         }
471         if (printk_ratelimit())
472                 pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
473                         size);
474         kfree(va);
475         return ERR_PTR(-EBUSY);
476 }
477 
478 static void __free_vmap_area(struct vmap_area *va)
479 {
480         BUG_ON(RB_EMPTY_NODE(&va->rb_node));
481 
482         if (free_vmap_cache) {
483                 if (va->va_end < cached_vstart) {
484                         free_vmap_cache = NULL;
485                 } else {
486                         struct vmap_area *cache;
487                         cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
488                         if (va->va_start <= cache->va_start) {
489                                 free_vmap_cache = rb_prev(&va->rb_node);
490                                 /*
491                                  * We don't try to update cached_hole_size or
492                                  * cached_align, but it won't go very wrong.
493                                  */
494                         }
495                 }
496         }
497         rb_erase(&va->rb_node, &vmap_area_root);
498         RB_CLEAR_NODE(&va->rb_node);
499         list_del_rcu(&va->list);
500 
501         /*
502          * Track the highest possible candidate for pcpu area
503          * allocation.  Areas outside of vmalloc area can be returned
504          * here too, consider only end addresses which fall inside
505          * vmalloc area proper.
506          */
507         if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
508                 vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
509 
510         kfree_rcu(va, rcu_head);
511 }
512 
513 /*
514  * Free a region of KVA allocated by alloc_vmap_area
515  */
516 static void free_vmap_area(struct vmap_area *va)
517 {
518         spin_lock(&vmap_area_lock);
519         __free_vmap_area(va);
520         spin_unlock(&vmap_area_lock);
521 }
522 
523 /*
524  * Clear the pagetable entries of a given vmap_area
525  */
526 static void unmap_vmap_area(struct vmap_area *va)
527 {
528         vunmap_page_range(va->va_start, va->va_end);
529 }
530 
531 static void vmap_debug_free_range(unsigned long start, unsigned long end)
532 {
533         /*
534          * Unmap page tables and force a TLB flush immediately if pagealloc
535          * debugging is enabled.  This catches use after free bugs similarly to
536          * those in linear kernel virtual address space after a page has been
537          * freed.
538          *
539          * All the lazy freeing logic is still retained, in order to minimise
540          * intrusiveness of this debugging feature.
541          *
542          * This is going to be *slow* (linear kernel virtual address debugging
543          * doesn't do a broadcast TLB flush so it is a lot faster).
544          */
545         if (debug_pagealloc_enabled()) {
546                 vunmap_page_range(start, end);
547                 flush_tlb_kernel_range(start, end);
548         }
549 }
550 
551 /*
552  * lazy_max_pages is the maximum amount of virtual address space we gather up
553  * before attempting to purge with a TLB flush.
554  *
555  * There is a tradeoff here: a larger number will cover more kernel page tables
556  * and take slightly longer to purge, but it will linearly reduce the number of
557  * global TLB flushes that must be performed. It would seem natural to scale
558  * this number up linearly with the number of CPUs (because vmapping activity
559  * could also scale linearly with the number of CPUs), however it is likely
560  * that in practice, workloads might be constrained in other ways that mean
561  * vmap activity will not scale linearly with CPUs. Also, I want to be
562  * conservative and not introduce a big latency on huge systems, so go with
563  * a less aggressive log scale. It will still be an improvement over the old
564  * code, and it will be simple to change the scale factor if we find that it
565  * becomes a problem on bigger systems.
566  */
567 static unsigned long lazy_max_pages(void)
568 {
569         unsigned int log;
570 
571         log = fls(num_online_cpus());
572 
573         return log * (32UL * 1024 * 1024 / PAGE_SIZE);
574 }
575 
576 static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
577 
578 /* for per-CPU blocks */
579 static void purge_fragmented_blocks_allcpus(void);
580 
581 /*
582  * called before a call to iounmap() if the caller wants vm_area_struct's
583  * immediately freed.
584  */
585 void set_iounmap_nonlazy(void)
586 {
587         atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
588 }
589 
590 /*
591  * Purges all lazily-freed vmap areas.
592  *
593  * If sync is 0 then don't purge if there is already a purge in progress.
594  * If force_flush is 1, then flush kernel TLBs between *start and *end even
595  * if we found no lazy vmap areas to unmap (callers can use this to optimise
596  * their own TLB flushing).
597  * Returns with *start = min(*start, lowest purged address)
598  *              *end = max(*end, highest purged address)
599  */
600 static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
601                                         int sync, int force_flush)
602 {
603         static DEFINE_SPINLOCK(purge_lock);
604         LIST_HEAD(valist);
605         struct vmap_area *va;
606         struct vmap_area *n_va;
607         int nr = 0;
608 
609         /*
610          * If sync is 0 but force_flush is 1, we'll go sync anyway but callers
611          * should not expect such behaviour. This just simplifies locking for
612          * the case that isn't actually used at the moment anyway.
613          */
614         if (!sync && !force_flush) {
615                 if (!spin_trylock(&purge_lock))
616                         return;
617         } else
618                 spin_lock(&purge_lock);
619 
620         if (sync)
621                 purge_fragmented_blocks_allcpus();
622 
623         rcu_read_lock();
624         list_for_each_entry_rcu(va, &vmap_area_list, list) {
625                 if (va->flags & VM_LAZY_FREE) {
626                         if (va->va_start < *start)
627                                 *start = va->va_start;
628                         if (va->va_end > *end)
629                                 *end = va->va_end;
630                         nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
631                         list_add_tail(&va->purge_list, &valist);
632                         va->flags |= VM_LAZY_FREEING;
633                         va->flags &= ~VM_LAZY_FREE;
634                 }
635         }
636         rcu_read_unlock();
637 
638         if (nr)
639                 atomic_sub(nr, &vmap_lazy_nr);
640 
641         if (nr || force_flush)
642                 flush_tlb_kernel_range(*start, *end);
643 
644         if (nr) {
645                 spin_lock(&vmap_area_lock);
646                 list_for_each_entry_safe(va, n_va, &valist, purge_list)
647                         __free_vmap_area(va);
648                 spin_unlock(&vmap_area_lock);
649         }
650         spin_unlock(&purge_lock);
651 }
652 
653 /*
654  * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
655  * is already purging.
656  */
657 static void try_purge_vmap_area_lazy(void)
658 {
659         unsigned long start = ULONG_MAX, end = 0;
660 
661         __purge_vmap_area_lazy(&start, &end, 0, 0);
662 }
663 
664 /*
665  * Kick off a purge of the outstanding lazy areas.
666  */
667 static void purge_vmap_area_lazy(void)
668 {
669         unsigned long start = ULONG_MAX, end = 0;
670 
671         __purge_vmap_area_lazy(&start, &end, 1, 0);
672 }
673 
674 /*
675  * Free a vmap area, caller ensuring that the area has been unmapped
676  * and flush_cache_vunmap had been called for the correct range
677  * previously.
678  */
679 static void free_vmap_area_noflush(struct vmap_area *va)
680 {
681         va->flags |= VM_LAZY_FREE;
682         atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr);
683         if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages()))
684                 try_purge_vmap_area_lazy();
685 }
686 
687 /*
688  * Free and unmap a vmap area, caller ensuring flush_cache_vunmap had been
689  * called for the correct range previously.
690  */
691 static void free_unmap_vmap_area_noflush(struct vmap_area *va)
692 {
693         unmap_vmap_area(va);
694         free_vmap_area_noflush(va);
695 }
696 
697 /*
698  * Free and unmap a vmap area
699  */
700 static void free_unmap_vmap_area(struct vmap_area *va)
701 {
702         flush_cache_vunmap(va->va_start, va->va_end);
703         free_unmap_vmap_area_noflush(va);
704 }
705 
706 static struct vmap_area *find_vmap_area(unsigned long addr)
707 {
708         struct vmap_area *va;
709 
710         spin_lock(&vmap_area_lock);
711         va = __find_vmap_area(addr);
712         spin_unlock(&vmap_area_lock);
713 
714         return va;
715 }
716 
717 static void free_unmap_vmap_area_addr(unsigned long addr)
718 {
719         struct vmap_area *va;
720 
721         va = find_vmap_area(addr);
722         BUG_ON(!va);
723         free_unmap_vmap_area(va);
724 }
725 
726 
727 /*** Per cpu kva allocator ***/
728 
729 /*
730  * vmap space is limited especially on 32 bit architectures. Ensure there is
731  * room for at least 16 percpu vmap blocks per CPU.
732  */
733 /*
734  * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
735  * to #define VMALLOC_SPACE             (VMALLOC_END-VMALLOC_START). Guess
736  * instead (we just need a rough idea)
737  */
738 #if BITS_PER_LONG == 32
739 #define VMALLOC_SPACE           (128UL*1024*1024)
740 #else
741 #define VMALLOC_SPACE           (128UL*1024*1024*1024)
742 #endif
743 
744 #define VMALLOC_PAGES           (VMALLOC_SPACE / PAGE_SIZE)
745 #define VMAP_MAX_ALLOC          BITS_PER_LONG   /* 256K with 4K pages */
746 #define VMAP_BBMAP_BITS_MAX     1024    /* 4MB with 4K pages */
747 #define VMAP_BBMAP_BITS_MIN     (VMAP_MAX_ALLOC*2)
748 #define VMAP_MIN(x, y)          ((x) < (y) ? (x) : (y)) /* can't use min() */
749 #define VMAP_MAX(x, y)          ((x) > (y) ? (x) : (y)) /* can't use max() */
750 #define VMAP_BBMAP_BITS         \
751                 VMAP_MIN(VMAP_BBMAP_BITS_MAX,   \
752                 VMAP_MAX(VMAP_BBMAP_BITS_MIN,   \
753                         VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
754 
755 #define VMAP_BLOCK_SIZE         (VMAP_BBMAP_BITS * PAGE_SIZE)
756 
757 static bool vmap_initialized __read_mostly = false;
758 
759 struct vmap_block_queue {
760         spinlock_t lock;
761         struct list_head free;
762 };
763 
764 struct vmap_block {
765         spinlock_t lock;
766         struct vmap_area *va;
767         unsigned long free, dirty;
768         unsigned long dirty_min, dirty_max; /*< dirty range */
769         struct list_head free_list;
770         struct rcu_head rcu_head;
771         struct list_head purge;
772 };
773 
774 /* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
775 static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
776 
777 /*
778  * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
779  * in the free path. Could get rid of this if we change the API to return a
780  * "cookie" from alloc, to be passed to free. But no big deal yet.
781  */
782 static DEFINE_SPINLOCK(vmap_block_tree_lock);
783 static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
784 
785 /*
786  * We should probably have a fallback mechanism to allocate virtual memory
787  * out of partially filled vmap blocks. However vmap block sizing should be
788  * fairly reasonable according to the vmalloc size, so it shouldn't be a
789  * big problem.
790  */
791 
792 static unsigned long addr_to_vb_idx(unsigned long addr)
793 {
794         addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
795         addr /= VMAP_BLOCK_SIZE;
796         return addr;
797 }
798 
799 static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
800 {
801         unsigned long addr;
802 
803         addr = va_start + (pages_off << PAGE_SHIFT);
804         BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start));
805         return (void *)addr;
806 }
807 
808 /**
809  * new_vmap_block - allocates new vmap_block and occupies 2^order pages in this
810  *                  block. Of course pages number can't exceed VMAP_BBMAP_BITS
811  * @order:    how many 2^order pages should be occupied in newly allocated block
812  * @gfp_mask: flags for the page level allocator
813  *
814  * Returns: virtual address in a newly allocated block or ERR_PTR(-errno)
815  */
816 static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
817 {
818         struct vmap_block_queue *vbq;
819         struct vmap_block *vb;
820         struct vmap_area *va;
821         unsigned long vb_idx;
822         int node, err;
823         void *vaddr;
824 
825         node = numa_node_id();
826 
827         vb = kmalloc_node(sizeof(struct vmap_block),
828                         gfp_mask & GFP_RECLAIM_MASK, node);
829         if (unlikely(!vb))
830                 return ERR_PTR(-ENOMEM);
831 
832         va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
833                                         VMALLOC_START, VMALLOC_END,
834                                         node, gfp_mask);
835         if (IS_ERR(va)) {
836                 kfree(vb);
837                 return ERR_CAST(va);
838         }
839 
840         err = radix_tree_preload(gfp_mask);
841         if (unlikely(err)) {
842                 kfree(vb);
843                 free_vmap_area(va);
844                 return ERR_PTR(err);
845         }
846 
847         vaddr = vmap_block_vaddr(va->va_start, 0);
848         spin_lock_init(&vb->lock);
849         vb->va = va;
850         /* At least something should be left free */
851         BUG_ON(VMAP_BBMAP_BITS <= (1UL << order));
852         vb->free = VMAP_BBMAP_BITS - (1UL << order);
853         vb->dirty = 0;
854         vb->dirty_min = VMAP_BBMAP_BITS;
855         vb->dirty_max = 0;
856         INIT_LIST_HEAD(&vb->free_list);
857 
858         vb_idx = addr_to_vb_idx(va->va_start);
859         spin_lock(&vmap_block_tree_lock);
860         err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
861         spin_unlock(&vmap_block_tree_lock);
862         BUG_ON(err);
863         radix_tree_preload_end();
864 
865         vbq = &get_cpu_var(vmap_block_queue);
866         spin_lock(&vbq->lock);
867         list_add_tail_rcu(&vb->free_list, &vbq->free);
868         spin_unlock(&vbq->lock);
869         put_cpu_var(vmap_block_queue);
870 
871         return vaddr;
872 }
873 
874 static void free_vmap_block(struct vmap_block *vb)
875 {
876         struct vmap_block *tmp;
877         unsigned long vb_idx;
878 
879         vb_idx = addr_to_vb_idx(vb->va->va_start);
880         spin_lock(&vmap_block_tree_lock);
881         tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
882         spin_unlock(&vmap_block_tree_lock);
883         BUG_ON(tmp != vb);
884 
885         free_vmap_area_noflush(vb->va);
886         kfree_rcu(vb, rcu_head);
887 }
888 
889 static void purge_fragmented_blocks(int cpu)
890 {
891         LIST_HEAD(purge);
892         struct vmap_block *vb;
893         struct vmap_block *n_vb;
894         struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
895 
896         rcu_read_lock();
897         list_for_each_entry_rcu(vb, &vbq->free, free_list) {
898 
899                 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
900                         continue;
901 
902                 spin_lock(&vb->lock);
903                 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
904                         vb->free = 0; /* prevent further allocs after releasing lock */
905                         vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
906                         vb->dirty_min = 0;
907                         vb->dirty_max = VMAP_BBMAP_BITS;
908                         spin_lock(&vbq->lock);
909                         list_del_rcu(&vb->free_list);
910                         spin_unlock(&vbq->lock);
911                         spin_unlock(&vb->lock);
912                         list_add_tail(&vb->purge, &purge);
913                 } else
914                         spin_unlock(&vb->lock);
915         }
916         rcu_read_unlock();
917 
918         list_for_each_entry_safe(vb, n_vb, &purge, purge) {
919                 list_del(&vb->purge);
920                 free_vmap_block(vb);
921         }
922 }
923 
924 static void purge_fragmented_blocks_allcpus(void)
925 {
926         int cpu;
927 
928         for_each_possible_cpu(cpu)
929                 purge_fragmented_blocks(cpu);
930 }
931 
932 static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
933 {
934         struct vmap_block_queue *vbq;
935         struct vmap_block *vb;
936         void *vaddr = NULL;
937         unsigned int order;
938 
939         BUG_ON(offset_in_page(size));
940         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
941         if (WARN_ON(size == 0)) {
942                 /*
943                  * Allocating 0 bytes isn't what caller wants since
944                  * get_order(0) returns funny result. Just warn and terminate
945                  * early.
946                  */
947                 return NULL;
948         }
949         order = get_order(size);
950 
951         rcu_read_lock();
952         vbq = &get_cpu_var(vmap_block_queue);
953         list_for_each_entry_rcu(vb, &vbq->free, free_list) {
954                 unsigned long pages_off;
955 
956                 spin_lock(&vb->lock);
957                 if (vb->free < (1UL << order)) {
958                         spin_unlock(&vb->lock);
959                         continue;
960                 }
961 
962                 pages_off = VMAP_BBMAP_BITS - vb->free;
963                 vaddr = vmap_block_vaddr(vb->va->va_start, pages_off);
964                 vb->free -= 1UL << order;
965                 if (vb->free == 0) {
966                         spin_lock(&vbq->lock);
967                         list_del_rcu(&vb->free_list);
968                         spin_unlock(&vbq->lock);
969                 }
970 
971                 spin_unlock(&vb->lock);
972                 break;
973         }
974 
975         put_cpu_var(vmap_block_queue);
976         rcu_read_unlock();
977 
978         /* Allocate new block if nothing was found */
979         if (!vaddr)
980                 vaddr = new_vmap_block(order, gfp_mask);
981 
982         return vaddr;
983 }
984 
985 static void vb_free(const void *addr, unsigned long size)
986 {
987         unsigned long offset;
988         unsigned long vb_idx;
989         unsigned int order;
990         struct vmap_block *vb;
991 
992         BUG_ON(offset_in_page(size));
993         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
994 
995         flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
996 
997         order = get_order(size);
998 
999         offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
1000         offset >>= PAGE_SHIFT;
1001 
1002         vb_idx = addr_to_vb_idx((unsigned long)addr);
1003         rcu_read_lock();
1004         vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
1005         rcu_read_unlock();
1006         BUG_ON(!vb);
1007 
1008         vunmap_page_range((unsigned long)addr, (unsigned long)addr + size);
1009 
1010         spin_lock(&vb->lock);
1011 
1012         /* Expand dirty range */
1013         vb->dirty_min = min(vb->dirty_min, offset);
1014         vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
1015 
1016         vb->dirty += 1UL << order;
1017         if (vb->dirty == VMAP_BBMAP_BITS) {
1018                 BUG_ON(vb->free);
1019                 spin_unlock(&vb->lock);
1020                 free_vmap_block(vb);
1021         } else
1022                 spin_unlock(&vb->lock);
1023 }
1024 
1025 /**
1026  * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
1027  *
1028  * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
1029  * to amortize TLB flushing overheads. What this means is that any page you
1030  * have now, may, in a former life, have been mapped into kernel virtual
1031  * address by the vmap layer and so there might be some CPUs with TLB entries
1032  * still referencing that page (additional to the regular 1:1 kernel mapping).
1033  *
1034  * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
1035  * be sure that none of the pages we have control over will have any aliases
1036  * from the vmap layer.
1037  */
1038 void vm_unmap_aliases(void)
1039 {
1040         unsigned long start = ULONG_MAX, end = 0;
1041         int cpu;
1042         int flush = 0;
1043 
1044         if (unlikely(!vmap_initialized))
1045                 return;
1046 
1047         for_each_possible_cpu(cpu) {
1048                 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1049                 struct vmap_block *vb;
1050 
1051                 rcu_read_lock();
1052                 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1053                         spin_lock(&vb->lock);
1054                         if (vb->dirty) {
1055                                 unsigned long va_start = vb->va->va_start;
1056                                 unsigned long s, e;
1057 
1058                                 s = va_start + (vb->dirty_min << PAGE_SHIFT);
1059                                 e = va_start + (vb->dirty_max << PAGE_SHIFT);
1060 
1061                                 start = min(s, start);
1062                                 end   = max(e, end);
1063 
1064                                 flush = 1;
1065                         }
1066                         spin_unlock(&vb->lock);
1067                 }
1068                 rcu_read_unlock();
1069         }
1070 
1071         __purge_vmap_area_lazy(&start, &end, 1, flush);
1072 }
1073 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
1074 
1075 /**
1076  * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
1077  * @mem: the pointer returned by vm_map_ram
1078  * @count: the count passed to that vm_map_ram call (cannot unmap partial)
1079  */
1080 void vm_unmap_ram(const void *mem, unsigned int count)
1081 {
1082         unsigned long size = count << PAGE_SHIFT;
1083         unsigned long addr = (unsigned long)mem;
1084 
1085         BUG_ON(!addr);
1086         BUG_ON(addr < VMALLOC_START);
1087         BUG_ON(addr > VMALLOC_END);
1088         BUG_ON(!PAGE_ALIGNED(addr));
1089 
1090         debug_check_no_locks_freed(mem, size);
1091         vmap_debug_free_range(addr, addr+size);
1092 
1093         if (likely(count <= VMAP_MAX_ALLOC))
1094                 vb_free(mem, size);
1095         else
1096                 free_unmap_vmap_area_addr(addr);
1097 }
1098 EXPORT_SYMBOL(vm_unmap_ram);
1099 
1100 /**
1101  * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
1102  * @pages: an array of pointers to the pages to be mapped
1103  * @count: number of pages
1104  * @node: prefer to allocate data structures on this node
1105  * @prot: memory protection to use. PAGE_KERNEL for regular RAM
1106  *
1107  * If you use this function for less than VMAP_MAX_ALLOC pages, it could be
1108  * faster than vmap so it's good.  But if you mix long-life and short-life
1109  * objects with vm_map_ram(), it could consume lots of address space through
1110  * fragmentation (especially on a 32bit machine).  You could see failures in
1111  * the end.  Please use this function for short-lived objects.
1112  *
1113  * Returns: a pointer to the address that has been mapped, or %NULL on failure
1114  */
1115 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
1116 {
1117         unsigned long size = count << PAGE_SHIFT;
1118         unsigned long addr;
1119         void *mem;
1120 
1121         if (likely(count <= VMAP_MAX_ALLOC)) {
1122                 mem = vb_alloc(size, GFP_KERNEL);
1123                 if (IS_ERR(mem))
1124                         return NULL;
1125                 addr = (unsigned long)mem;
1126         } else {
1127                 struct vmap_area *va;
1128                 va = alloc_vmap_area(size, PAGE_SIZE,
1129                                 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1130                 if (IS_ERR(va))
1131                         return NULL;
1132 
1133                 addr = va->va_start;
1134                 mem = (void *)addr;
1135         }
1136         if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
1137                 vm_unmap_ram(mem, count);
1138                 return NULL;
1139         }
1140         return mem;
1141 }
1142 EXPORT_SYMBOL(vm_map_ram);
1143 
1144 static struct vm_struct *vmlist __initdata;
1145 /**
1146  * vm_area_add_early - add vmap area early during boot
1147  * @vm: vm_struct to add
1148  *
1149  * This function is used to add fixed kernel vm area to vmlist before
1150  * vmalloc_init() is called.  @vm->addr, @vm->size, and @vm->flags
1151  * should contain proper values and the other fields should be zero.
1152  *
1153  * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1154  */
1155 void __init vm_area_add_early(struct vm_struct *vm)
1156 {
1157         struct vm_struct *tmp, **p;
1158 
1159         BUG_ON(vmap_initialized);
1160         for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1161                 if (tmp->addr >= vm->addr) {
1162                         BUG_ON(tmp->addr < vm->addr + vm->size);
1163                         break;
1164                 } else
1165                         BUG_ON(tmp->addr + tmp->size > vm->addr);
1166         }
1167         vm->next = *p;
1168         *p = vm;
1169 }
1170 
1171 /**
1172  * vm_area_register_early - register vmap area early during boot
1173  * @vm: vm_struct to register
1174  * @align: requested alignment
1175  *
1176  * This function is used to register kernel vm area before
1177  * vmalloc_init() is called.  @vm->size and @vm->flags should contain
1178  * proper values on entry and other fields should be zero.  On return,
1179  * vm->addr contains the allocated address.
1180  *
1181  * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1182  */
1183 void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1184 {
1185         static size_t vm_init_off __initdata;
1186         unsigned long addr;
1187 
1188         addr = ALIGN(VMALLOC_START + vm_init_off, align);
1189         vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1190 
1191         vm->addr = (void *)addr;
1192 
1193         vm_area_add_early(vm);
1194 }
1195 
1196 void __init vmalloc_init(void)
1197 {
1198         struct vmap_area *va;
1199         struct vm_struct *tmp;
1200         int i;
1201 
1202         for_each_possible_cpu(i) {
1203                 struct vmap_block_queue *vbq;
1204                 struct vfree_deferred *p;
1205 
1206                 vbq = &per_cpu(vmap_block_queue, i);
1207                 spin_lock_init(&vbq->lock);
1208                 INIT_LIST_HEAD(&vbq->free);
1209                 p = &per_cpu(vfree_deferred, i);
1210                 init_llist_head(&p->list);
1211                 INIT_WORK(&p->wq, free_work);
1212         }
1213 
1214         /* Import existing vmlist entries. */
1215         for (tmp = vmlist; tmp; tmp = tmp->next) {
1216                 va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
1217                 va->flags = VM_VM_AREA;
1218                 va->va_start = (unsigned long)tmp->addr;
1219                 va->va_end = va->va_start + tmp->size;
1220                 va->vm = tmp;
1221                 __insert_vmap_area(va);
1222         }
1223 
1224         vmap_area_pcpu_hole = VMALLOC_END;
1225 
1226         vmap_initialized = true;
1227 }
1228 
1229 /**
1230  * map_kernel_range_noflush - map kernel VM area with the specified pages
1231  * @addr: start of the VM area to map
1232  * @size: size of the VM area to map
1233  * @prot: page protection flags to use
1234  * @pages: pages to map
1235  *
1236  * Map PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1237  * specify should have been allocated using get_vm_area() and its
1238  * friends.
1239  *
1240  * NOTE:
1241  * This function does NOT do any cache flushing.  The caller is
1242  * responsible for calling flush_cache_vmap() on to-be-mapped areas
1243  * before calling this function.
1244  *
1245  * RETURNS:
1246  * The number of pages mapped on success, -errno on failure.
1247  */
1248 int map_kernel_range_noflush(unsigned long addr, unsigned long size,
1249                              pgprot_t prot, struct page **pages)
1250 {
1251         return vmap_page_range_noflush(addr, addr + size, prot, pages);
1252 }
1253 
1254 /**
1255  * unmap_kernel_range_noflush - unmap kernel VM area
1256  * @addr: start of the VM area to unmap
1257  * @size: size of the VM area to unmap
1258  *
1259  * Unmap PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1260  * specify should have been allocated using get_vm_area() and its
1261  * friends.
1262  *
1263  * NOTE:
1264  * This function does NOT do any cache flushing.  The caller is
1265  * responsible for calling flush_cache_vunmap() on to-be-mapped areas
1266  * before calling this function and flush_tlb_kernel_range() after.
1267  */
1268 void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
1269 {
1270         vunmap_page_range(addr, addr + size);
1271 }
1272 EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush);
1273 
1274 /**
1275  * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
1276  * @addr: start of the VM area to unmap
1277  * @size: size of the VM area to unmap
1278  *
1279  * Similar to unmap_kernel_range_noflush() but flushes vcache before
1280  * the unmapping and tlb after.
1281  */
1282 void unmap_kernel_range(unsigned long addr, unsigned long size)
1283 {
1284         unsigned long end = addr + size;
1285 
1286         flush_cache_vunmap(addr, end);
1287         vunmap_page_range(addr, end);
1288         flush_tlb_kernel_range(addr, end);
1289 }
1290 EXPORT_SYMBOL_GPL(unmap_kernel_range);
1291 
1292 int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages)
1293 {
1294         unsigned long addr = (unsigned long)area->addr;
1295         unsigned long end = addr + get_vm_area_size(area);
1296         int err;
1297 
1298         err = vmap_page_range(addr, end, prot, pages);
1299 
1300         return err > 0 ? 0 : err;
1301 }
1302 EXPORT_SYMBOL_GPL(map_vm_area);
1303 
1304 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1305                               unsigned long flags, const void *caller)
1306 {
1307         spin_lock(&vmap_area_lock);
1308         vm->flags = flags;
1309         vm->addr = (void *)va->va_start;
1310         vm->size = va->va_end - va->va_start;
1311         vm->caller = caller;
1312         va->vm = vm;
1313         va->flags |= VM_VM_AREA;
1314         spin_unlock(&vmap_area_lock);
1315 }
1316 
1317 static void clear_vm_uninitialized_flag(struct vm_struct *vm)
1318 {
1319         /*
1320          * Before removing VM_UNINITIALIZED,
1321          * we should make sure that vm has proper values.
1322          * Pair with smp_rmb() in show_numa_info().
1323          */
1324         smp_wmb();
1325         vm->flags &= ~VM_UNINITIALIZED;
1326 }
1327 
1328 static struct vm_struct *__get_vm_area_node(unsigned long size,
1329                 unsigned long align, unsigned long flags, unsigned long start,
1330                 unsigned long end, int node, gfp_t gfp_mask, const void *caller)
1331 {
1332         struct vmap_area *va;
1333         struct vm_struct *area;
1334 
1335         BUG_ON(in_interrupt());
1336         if (flags & VM_IOREMAP)
1337                 align = 1ul << clamp_t(int, fls_long(size),
1338                                        PAGE_SHIFT, IOREMAP_MAX_ORDER);
1339 
1340         size = PAGE_ALIGN(size);
1341         if (unlikely(!size))
1342                 return NULL;
1343 
1344         area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
1345         if (unlikely(!area))
1346                 return NULL;
1347 
1348         if (!(flags & VM_NO_GUARD))
1349                 size += PAGE_SIZE;
1350 
1351         va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
1352         if (IS_ERR(va)) {
1353                 kfree(area);
1354                 return NULL;
1355         }
1356 
1357         setup_vmalloc_vm(area, va, flags, caller);
1358 
1359         return area;
1360 }
1361 
1362 struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
1363                                 unsigned long start, unsigned long end)
1364 {
1365         return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1366                                   GFP_KERNEL, __builtin_return_address(0));
1367 }
1368 EXPORT_SYMBOL_GPL(__get_vm_area);
1369 
1370 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
1371                                        unsigned long start, unsigned long end,
1372                                        const void *caller)
1373 {
1374         return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1375                                   GFP_KERNEL, caller);
1376 }
1377 
1378 /**
1379  *      get_vm_area  -  reserve a contiguous kernel virtual area
1380  *      @size:          size of the area
1381  *      @flags:         %VM_IOREMAP for I/O mappings or VM_ALLOC
1382  *
1383  *      Search an area of @size in the kernel virtual mapping area,
1384  *      and reserved it for out purposes.  Returns the area descriptor
1385  *      on success or %NULL on failure.
1386  */
1387 struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
1388 {
1389         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1390                                   NUMA_NO_NODE, GFP_KERNEL,
1391                                   __builtin_return_address(0));
1392 }
1393 
1394 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
1395                                 const void *caller)
1396 {
1397         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1398                                   NUMA_NO_NODE, GFP_KERNEL, caller);
1399 }
1400 
1401 /**
1402  *      find_vm_area  -  find a continuous kernel virtual area
1403  *      @addr:          base address
1404  *
1405  *      Search for the kernel VM area starting at @addr, and return it.
1406  *      It is up to the caller to do all required locking to keep the returned
1407  *      pointer valid.
1408  */
1409 struct vm_struct *find_vm_area(const void *addr)
1410 {
1411         struct vmap_area *va;
1412 
1413         va = find_vmap_area((unsigned long)addr);
1414         if (va && va->flags & VM_VM_AREA)
1415                 return va->vm;
1416 
1417         return NULL;
1418 }
1419 
1420 /**
1421  *      remove_vm_area  -  find and remove a continuous kernel virtual area
1422  *      @addr:          base address
1423  *
1424  *      Search for the kernel VM area starting at @addr, and remove it.
1425  *      This function returns the found VM area, but using it is NOT safe
1426  *      on SMP machines, except for its size or flags.
1427  */
1428 struct vm_struct *remove_vm_area(const void *addr)
1429 {
1430         struct vmap_area *va;
1431 
1432         va = find_vmap_area((unsigned long)addr);
1433         if (va && va->flags & VM_VM_AREA) {
1434                 struct vm_struct *vm = va->vm;
1435 
1436                 spin_lock(&vmap_area_lock);
1437                 va->vm = NULL;
1438                 va->flags &= ~VM_VM_AREA;
1439                 spin_unlock(&vmap_area_lock);
1440 
1441                 vmap_debug_free_range(va->va_start, va->va_end);
1442                 kasan_free_shadow(vm);
1443                 free_unmap_vmap_area(va);
1444 
1445                 return vm;
1446         }
1447         return NULL;
1448 }
1449 
1450 static void __vunmap(const void *addr, int deallocate_pages)
1451 {
1452         struct vm_struct *area;
1453 
1454         if (!addr)
1455                 return;
1456 
1457         if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n",
1458                         addr))
1459                 return;
1460 
1461         area = remove_vm_area(addr);
1462         if (unlikely(!area)) {
1463                 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
1464                                 addr);
1465                 return;
1466         }
1467 
1468         debug_check_no_locks_freed(addr, get_vm_area_size(area));
1469         debug_check_no_obj_freed(addr, get_vm_area_size(area));
1470 
1471         if (deallocate_pages) {
1472                 int i;
1473 
1474                 for (i = 0; i < area->nr_pages; i++) {
1475                         struct page *page = area->pages[i];
1476 
1477                         BUG_ON(!page);
1478                         __free_kmem_pages(page, 0);
1479                 }
1480 
1481                 kvfree(area->pages);
1482         }
1483 
1484         kfree(area);
1485         return;
1486 }
1487  
1488 /**
1489  *      vfree  -  release memory allocated by vmalloc()
1490  *      @addr:          memory base address
1491  *
1492  *      Free the virtually continuous memory area starting at @addr, as
1493  *      obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
1494  *      NULL, no operation is performed.
1495  *
1496  *      Must not be called in NMI context (strictly speaking, only if we don't
1497  *      have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
1498  *      conventions for vfree() arch-depenedent would be a really bad idea)
1499  *
1500  *      NOTE: assumes that the object at *addr has a size >= sizeof(llist_node)
1501  */
1502 void vfree(const void *addr)
1503 {
1504         BUG_ON(in_nmi());
1505 
1506         kmemleak_free(addr);
1507 
1508         if (!addr)
1509                 return;
1510         if (unlikely(in_interrupt())) {
1511                 struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
1512                 if (llist_add((struct llist_node *)addr, &p->list))
1513                         schedule_work(&p->wq);
1514         } else
1515                 __vunmap(addr, 1);
1516 }
1517 EXPORT_SYMBOL(vfree);
1518 
1519 /**
1520  *      vunmap  -  release virtual mapping obtained by vmap()
1521  *      @addr:          memory base address
1522  *
1523  *      Free the virtually contiguous memory area starting at @addr,
1524  *      which was created from the page array passed to vmap().
1525  *
1526  *      Must not be called in interrupt context.
1527  */
1528 void vunmap(const void *addr)
1529 {
1530         BUG_ON(in_interrupt());
1531         might_sleep();
1532         if (addr)
1533                 __vunmap(addr, 0);
1534 }
1535 EXPORT_SYMBOL(vunmap);
1536 
1537 /**
1538  *      vmap  -  map an array of pages into virtually contiguous space
1539  *      @pages:         array of page pointers
1540  *      @count:         number of pages to map
1541  *      @flags:         vm_area->flags
1542  *      @prot:          page protection for the mapping
1543  *
1544  *      Maps @count pages from @pages into contiguous kernel virtual
1545  *      space.
1546  */
1547 void *vmap(struct page **pages, unsigned int count,
1548                 unsigned long flags, pgprot_t prot)
1549 {
1550         struct vm_struct *area;
1551 
1552         might_sleep();
1553 
1554         if (count > totalram_pages)
1555                 return NULL;
1556 
1557         area = get_vm_area_caller((count << PAGE_SHIFT), flags,
1558                                         __builtin_return_address(0));
1559         if (!area)
1560                 return NULL;
1561 
1562         if (map_vm_area(area, prot, pages)) {
1563                 vunmap(area->addr);
1564                 return NULL;
1565         }
1566 
1567         return area->addr;
1568 }
1569 EXPORT_SYMBOL(vmap);
1570 
1571 static void *__vmalloc_node(unsigned long size, unsigned long align,
1572                             gfp_t gfp_mask, pgprot_t prot,
1573                             int node, const void *caller);
1574 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
1575                                  pgprot_t prot, int node)
1576 {
1577         const int order = 0;
1578         struct page **pages;
1579         unsigned int nr_pages, array_size, i;
1580         const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
1581         const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
1582 
1583         nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
1584         array_size = (nr_pages * sizeof(struct page *));
1585 
1586         area->nr_pages = nr_pages;
1587         /* Please note that the recursion is strictly bounded. */
1588         if (array_size > PAGE_SIZE) {
1589                 pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM,
1590                                 PAGE_KERNEL, node, area->caller);
1591         } else {
1592                 pages = kmalloc_node(array_size, nested_gfp, node);
1593         }
1594         area->pages = pages;
1595         if (!area->pages) {
1596                 remove_vm_area(area->addr);
1597                 kfree(area);
1598                 return NULL;
1599         }
1600 
1601         for (i = 0; i < area->nr_pages; i++) {
1602                 struct page *page;
1603 
1604                 if (node == NUMA_NO_NODE)
1605                         page = alloc_kmem_pages(alloc_mask, order);
1606                 else
1607                         page = alloc_kmem_pages_node(node, alloc_mask, order);
1608 
1609                 if (unlikely(!page)) {
1610                         /* Successfully allocated i pages, free them in __vunmap() */
1611                         area->nr_pages = i;
1612                         goto fail;
1613                 }
1614                 area->pages[i] = page;
1615                 if (gfpflags_allow_blocking(gfp_mask))
1616                         cond_resched();
1617         }
1618 
1619         if (map_vm_area(area, prot, pages))
1620                 goto fail;
1621         return area->addr;
1622 
1623 fail:
1624         warn_alloc_failed(gfp_mask, order,
1625                           "vmalloc: allocation failure, allocated %ld of %ld bytes\n",
1626                           (area->nr_pages*PAGE_SIZE), area->size);
1627         vfree(area->addr);
1628         return NULL;
1629 }
1630 
1631 /**
1632  *      __vmalloc_node_range  -  allocate virtually contiguous memory
1633  *      @size:          allocation size
1634  *      @align:         desired alignment
1635  *      @start:         vm area range start
1636  *      @end:           vm area range end
1637  *      @gfp_mask:      flags for the page level allocator
1638  *      @prot:          protection mask for the allocated pages
1639  *      @vm_flags:      additional vm area flags (e.g. %VM_NO_GUARD)
1640  *      @node:          node to use for allocation or NUMA_NO_NODE
1641  *      @caller:        caller's return address
1642  *
1643  *      Allocate enough pages to cover @size from the page level
1644  *      allocator with @gfp_mask flags.  Map them into contiguous
1645  *      kernel virtual space, using a pagetable protection of @prot.
1646  */
1647 void *__vmalloc_node_range(unsigned long size, unsigned long align,
1648                         unsigned long start, unsigned long end, gfp_t gfp_mask,
1649                         pgprot_t prot, unsigned long vm_flags, int node,
1650                         const void *caller)
1651 {
1652         struct vm_struct *area;
1653         void *addr;
1654         unsigned long real_size = size;
1655 
1656         size = PAGE_ALIGN(size);
1657         if (!size || (size >> PAGE_SHIFT) > totalram_pages)
1658                 goto fail;
1659 
1660         area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED |
1661                                 vm_flags, start, end, node, gfp_mask, caller);
1662         if (!area)
1663                 goto fail;
1664 
1665         addr = __vmalloc_area_node(area, gfp_mask, prot, node);
1666         if (!addr)
1667                 return NULL;
1668 
1669         /*
1670          * In this function, newly allocated vm_struct has VM_UNINITIALIZED
1671          * flag. It means that vm_struct is not fully initialized.
1672          * Now, it is fully initialized, so remove this flag here.
1673          */
1674         clear_vm_uninitialized_flag(area);
1675 
1676         /*
1677          * A ref_count = 2 is needed because vm_struct allocated in
1678          * __get_vm_area_node() contains a reference to the virtual address of
1679          * the vmalloc'ed block.
1680          */
1681         kmemleak_alloc(addr, real_size, 2, gfp_mask);
1682 
1683         return addr;
1684 
1685 fail:
1686         warn_alloc_failed(gfp_mask, 0,
1687                           "vmalloc: allocation failure: %lu bytes\n",
1688                           real_size);
1689         return NULL;
1690 }
1691 
1692 /**
1693  *      __vmalloc_node  -  allocate virtually contiguous memory
1694  *      @size:          allocation size
1695  *      @align:         desired alignment
1696  *      @gfp_mask:      flags for the page level allocator
1697  *      @prot:          protection mask for the allocated pages
1698  *      @node:          node to use for allocation or NUMA_NO_NODE
1699  *      @caller:        caller's return address
1700  *
1701  *      Allocate enough pages to cover @size from the page level
1702  *      allocator with @gfp_mask flags.  Map them into contiguous
1703  *      kernel virtual space, using a pagetable protection of @prot.
1704  */
1705 static void *__vmalloc_node(unsigned long size, unsigned long align,
1706                             gfp_t gfp_mask, pgprot_t prot,
1707                             int node, const void *caller)
1708 {
1709         return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
1710                                 gfp_mask, prot, 0, node, caller);
1711 }
1712 
1713 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1714 {
1715         return __vmalloc_node(size, 1, gfp_mask, prot, NUMA_NO_NODE,
1716                                 __builtin_return_address(0));
1717 }
1718 EXPORT_SYMBOL(__vmalloc);
1719 
1720 static inline void *__vmalloc_node_flags(unsigned long size,
1721                                         int node, gfp_t flags)
1722 {
1723         return __vmalloc_node(size, 1, flags, PAGE_KERNEL,
1724                                         node, __builtin_return_address(0));
1725 }
1726 
1727 /**
1728  *      vmalloc  -  allocate virtually contiguous memory
1729  *      @size:          allocation size
1730  *      Allocate enough pages to cover @size from the page level
1731  *      allocator and map them into contiguous kernel virtual space.
1732  *
1733  *      For tight control over page level allocator and protection flags
1734  *      use __vmalloc() instead.
1735  */
1736 void *vmalloc(unsigned long size)
1737 {
1738         return __vmalloc_node_flags(size, NUMA_NO_NODE,
1739                                     GFP_KERNEL | __GFP_HIGHMEM);
1740 }
1741 EXPORT_SYMBOL(vmalloc);
1742 
1743 /**
1744  *      vzalloc - allocate virtually contiguous memory with zero fill
1745  *      @size:  allocation size
1746  *      Allocate enough pages to cover @size from the page level
1747  *      allocator and map them into contiguous kernel virtual space.
1748  *      The memory allocated is set to zero.
1749  *
1750  *      For tight control over page level allocator and protection flags
1751  *      use __vmalloc() instead.
1752  */
1753 void *vzalloc(unsigned long size)
1754 {
1755         return __vmalloc_node_flags(size, NUMA_NO_NODE,
1756                                 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1757 }
1758 EXPORT_SYMBOL(vzalloc);
1759 
1760 /**
1761  * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
1762  * @size: allocation size
1763  *
1764  * The resulting memory area is zeroed so it can be mapped to userspace
1765  * without leaking data.
1766  */
1767 void *vmalloc_user(unsigned long size)
1768 {
1769         struct vm_struct *area;
1770         void *ret;
1771 
1772         ret = __vmalloc_node(size, SHMLBA,
1773                              GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
1774                              PAGE_KERNEL, NUMA_NO_NODE,
1775                              __builtin_return_address(0));
1776         if (ret) {
1777                 area = find_vm_area(ret);
1778                 area->flags |= VM_USERMAP;
1779         }
1780         return ret;
1781 }
1782 EXPORT_SYMBOL(vmalloc_user);
1783 
1784 /**
1785  *      vmalloc_node  -  allocate memory on a specific node
1786  *      @size:          allocation size
1787  *      @node:          numa node
1788  *
1789  *      Allocate enough pages to cover @size from the page level
1790  *      allocator and map them into contiguous kernel virtual space.
1791  *
1792  *      For tight control over page level allocator and protection flags
1793  *      use __vmalloc() instead.
1794  */
1795 void *vmalloc_node(unsigned long size, int node)
1796 {
1797         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
1798                                         node, __builtin_return_address(0));
1799 }
1800 EXPORT_SYMBOL(vmalloc_node);
1801 
1802 /**
1803  * vzalloc_node - allocate memory on a specific node with zero fill
1804  * @size:       allocation size
1805  * @node:       numa node
1806  *
1807  * Allocate enough pages to cover @size from the page level
1808  * allocator and map them into contiguous kernel virtual space.
1809  * The memory allocated is set to zero.
1810  *
1811  * For tight control over page level allocator and protection flags
1812  * use __vmalloc_node() instead.
1813  */
1814 void *vzalloc_node(unsigned long size, int node)
1815 {
1816         return __vmalloc_node_flags(size, node,
1817                          GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1818 }
1819 EXPORT_SYMBOL(vzalloc_node);
1820 
1821 #ifndef PAGE_KERNEL_EXEC
1822 # define PAGE_KERNEL_EXEC PAGE_KERNEL
1823 #endif
1824 
1825 /**
1826  *      vmalloc_exec  -  allocate virtually contiguous, executable memory
1827  *      @size:          allocation size
1828  *
1829  *      Kernel-internal function to allocate enough pages to cover @size
1830  *      the page level allocator and map them into contiguous and
1831  *      executable kernel virtual space.
1832  *
1833  *      For tight control over page level allocator and protection flags
1834  *      use __vmalloc() instead.
1835  */
1836 
1837 void *vmalloc_exec(unsigned long size)
1838 {
1839         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
1840                               NUMA_NO_NODE, __builtin_return_address(0));
1841 }
1842 
1843 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
1844 #define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
1845 #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
1846 #define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
1847 #else
1848 #define GFP_VMALLOC32 GFP_KERNEL
1849 #endif
1850 
1851 /**
1852  *      vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
1853  *      @size:          allocation size
1854  *
1855  *      Allocate enough 32bit PA addressable pages to cover @size from the
1856  *      page level allocator and map them into contiguous kernel virtual space.
1857  */
1858 void *vmalloc_32(unsigned long size)
1859 {
1860         return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
1861                               NUMA_NO_NODE, __builtin_return_address(0));
1862 }
1863 EXPORT_SYMBOL(vmalloc_32);
1864 
1865 /**
1866  * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
1867  *      @size:          allocation size
1868  *
1869  * The resulting memory area is 32bit addressable and zeroed so it can be
1870  * mapped to userspace without leaking data.
1871  */
1872 void *vmalloc_32_user(unsigned long size)
1873 {
1874         struct vm_struct *area;
1875         void *ret;
1876 
1877         ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
1878                              NUMA_NO_NODE, __builtin_return_address(0));
1879         if (ret) {
1880                 area = find_vm_area(ret);
1881                 area->flags |= VM_USERMAP;
1882         }
1883         return ret;
1884 }
1885 EXPORT_SYMBOL(vmalloc_32_user);
1886 
1887 /*
1888  * small helper routine , copy contents to buf from addr.
1889  * If the page is not present, fill zero.
1890  */
1891 
1892 static int aligned_vread(char *buf, char *addr, unsigned long count)
1893 {
1894         struct page *p;
1895         int copied = 0;
1896 
1897         while (count) {
1898                 unsigned long offset, length;
1899 
1900                 offset = offset_in_page(addr);
1901                 length = PAGE_SIZE - offset;
1902                 if (length > count)
1903                         length = count;
1904                 p = vmalloc_to_page(addr);
1905                 /*
1906                  * To do safe access to this _mapped_ area, we need
1907                  * lock. But adding lock here means that we need to add
1908                  * overhead of vmalloc()/vfree() calles for this _debug_
1909                  * interface, rarely used. Instead of that, we'll use
1910                  * kmap() and get small overhead in this access function.
1911                  */
1912                 if (p) {
1913                         /*
1914                          * we can expect USER0 is not used (see vread/vwrite's
1915                          * function description)
1916                          */
1917                         void *map = kmap_atomic(p);
1918                         memcpy(buf, map + offset, length);
1919                         kunmap_atomic(map);
1920                 } else
1921                         memset(buf, 0, length);
1922 
1923                 addr += length;
1924                 buf += length;
1925                 copied += length;
1926                 count -= length;
1927         }
1928         return copied;
1929 }
1930 
1931 static int aligned_vwrite(char *buf, char *addr, unsigned long count)
1932 {
1933         struct page *p;
1934         int copied = 0;
1935 
1936         while (count) {
1937                 unsigned long offset, length;
1938 
1939                 offset = offset_in_page(addr);
1940                 length = PAGE_SIZE - offset;
1941                 if (length > count)
1942                         length = count;
1943                 p = vmalloc_to_page(addr);
1944                 /*
1945                  * To do safe access to this _mapped_ area, we need
1946                  * lock. But adding lock here means that we need to add
1947                  * overhead of vmalloc()/vfree() calles for this _debug_
1948                  * interface, rarely used. Instead of that, we'll use
1949                  * kmap() and get small overhead in this access function.
1950                  */
1951                 if (p) {
1952                         /*
1953                          * we can expect USER0 is not used (see vread/vwrite's
1954                          * function description)
1955                          */
1956                         void *map = kmap_atomic(p);
1957                         memcpy(map + offset, buf, length);
1958                         kunmap_atomic(map);
1959                 }
1960                 addr += length;
1961                 buf += length;
1962                 copied += length;
1963                 count -= length;
1964         }
1965         return copied;
1966 }
1967 
1968 /**
1969  *      vread() -  read vmalloc area in a safe way.
1970  *      @buf:           buffer for reading data
1971  *      @addr:          vm address.
1972  *      @count:         number of bytes to be read.
1973  *
1974  *      Returns # of bytes which addr and buf should be increased.
1975  *      (same number to @count). Returns 0 if [addr...addr+count) doesn't
1976  *      includes any intersect with alive vmalloc area.
1977  *
1978  *      This function checks that addr is a valid vmalloc'ed area, and
1979  *      copy data from that area to a given buffer. If the given memory range
1980  *      of [addr...addr+count) includes some valid address, data is copied to
1981  *      proper area of @buf. If there are memory holes, they'll be zero-filled.
1982  *      IOREMAP area is treated as memory hole and no copy is done.
1983  *
1984  *      If [addr...addr+count) doesn't includes any intersects with alive
1985  *      vm_struct area, returns 0. @buf should be kernel's buffer.
1986  *
1987  *      Note: In usual ops, vread() is never necessary because the caller
1988  *      should know vmalloc() area is valid and can use memcpy().
1989  *      This is for routines which have to access vmalloc area without
1990  *      any informaion, as /dev/kmem.
1991  *
1992  */
1993 
1994 long vread(char *buf, char *addr, unsigned long count)
1995 {
1996         struct vmap_area *va;
1997         struct vm_struct *vm;
1998         char *vaddr, *buf_start = buf;
1999         unsigned long buflen = count;
2000         unsigned long n;
2001 
2002         /* Don't allow overflow */
2003         if ((unsigned long) addr + count < count)
2004                 count = -(unsigned long) addr;
2005 
2006         spin_lock(&vmap_area_lock);
2007         list_for_each_entry(va, &vmap_area_list, list) {
2008                 if (!count)
2009                         break;
2010 
2011                 if (!(va->flags & VM_VM_AREA))
2012                         continue;
2013 
2014                 vm = va->vm;
2015                 vaddr = (char *) vm->addr;
2016                 if (addr >= vaddr + get_vm_area_size(vm))
2017                         continue;
2018                 while (addr < vaddr) {
2019                         if (count == 0)
2020                                 goto finished;
2021                         *buf = '\0';
2022                         buf++;
2023                         addr++;
2024                         count--;
2025                 }
2026                 n = vaddr + get_vm_area_size(vm) - addr;
2027                 if (n > count)
2028                         n = count;
2029                 if (!(vm->flags & VM_IOREMAP))
2030                         aligned_vread(buf, addr, n);
2031                 else /* IOREMAP area is treated as memory hole */
2032                         memset(buf, 0, n);
2033                 buf += n;
2034                 addr += n;
2035                 count -= n;
2036         }
2037 finished:
2038         spin_unlock(&vmap_area_lock);
2039 
2040         if (buf == buf_start)
2041                 return 0;
2042         /* zero-fill memory holes */
2043         if (buf != buf_start + buflen)
2044                 memset(buf, 0, buflen - (buf - buf_start));
2045 
2046         return buflen;
2047 }
2048 
2049 /**
2050  *      vwrite() -  write vmalloc area in a safe way.
2051  *      @buf:           buffer for source data
2052  *      @addr:          vm address.
2053  *      @count:         number of bytes to be read.
2054  *
2055  *      Returns # of bytes which addr and buf should be incresed.
2056  *      (same number to @count).
2057  *      If [addr...addr+count) doesn't includes any intersect with valid
2058  *      vmalloc area, returns 0.
2059  *
2060  *      This function checks that addr is a valid vmalloc'ed area, and
2061  *      copy data from a buffer to the given addr. If specified range of
2062  *      [addr...addr+count) includes some valid address, data is copied from
2063  *      proper area of @buf. If there are memory holes, no copy to hole.
2064  *      IOREMAP area is treated as memory hole and no copy is done.
2065  *
2066  *      If [addr...addr+count) doesn't includes any intersects with alive
2067  *      vm_struct area, returns 0. @buf should be kernel's buffer.
2068  *
2069  *      Note: In usual ops, vwrite() is never necessary because the caller
2070  *      should know vmalloc() area is valid and can use memcpy().
2071  *      This is for routines which have to access vmalloc area without
2072  *      any informaion, as /dev/kmem.
2073  */
2074 
2075 long vwrite(char *buf, char *addr, unsigned long count)
2076 {
2077         struct vmap_area *va;
2078         struct vm_struct *vm;
2079         char *vaddr;
2080         unsigned long n, buflen;
2081         int copied = 0;
2082 
2083         /* Don't allow overflow */
2084         if ((unsigned long) addr + count < count)
2085                 count = -(unsigned long) addr;
2086         buflen = count;
2087 
2088         spin_lock(&vmap_area_lock);
2089         list_for_each_entry(va, &vmap_area_list, list) {
2090                 if (!count)
2091                         break;
2092 
2093                 if (!(va->flags & VM_VM_AREA))
2094                         continue;
2095 
2096                 vm = va->vm;
2097                 vaddr = (char *) vm->addr;
2098                 if (addr >= vaddr + get_vm_area_size(vm))
2099                         continue;
2100                 while (addr < vaddr) {
2101                         if (count == 0)
2102                                 goto finished;
2103                         buf++;
2104                         addr++;
2105                         count--;
2106                 }
2107                 n = vaddr + get_vm_area_size(vm) - addr;
2108                 if (n > count)
2109                         n = count;
2110                 if (!(vm->flags & VM_IOREMAP)) {
2111                         aligned_vwrite(buf, addr, n);
2112                         copied++;
2113                 }
2114                 buf += n;
2115                 addr += n;
2116                 count -= n;
2117         }
2118 finished:
2119         spin_unlock(&vmap_area_lock);
2120         if (!copied)
2121                 return 0;
2122         return buflen;
2123 }
2124 
2125 /**
2126  *      remap_vmalloc_range_partial  -  map vmalloc pages to userspace
2127  *      @vma:           vma to cover
2128  *      @uaddr:         target user address to start at
2129  *      @kaddr:         virtual address of vmalloc kernel memory
2130  *      @size:          size of map area
2131  *
2132  *      Returns:        0 for success, -Exxx on failure
2133  *
2134  *      This function checks that @kaddr is a valid vmalloc'ed area,
2135  *      and that it is big enough to cover the range starting at
2136  *      @uaddr in @vma. Will return failure if that criteria isn't
2137  *      met.
2138  *
2139  *      Similar to remap_pfn_range() (see mm/memory.c)
2140  */
2141 int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
2142                                 void *kaddr, unsigned long size)
2143 {
2144         struct vm_struct *area;
2145 
2146         size = PAGE_ALIGN(size);
2147 
2148         if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr))
2149                 return -EINVAL;
2150 
2151         area = find_vm_area(kaddr);
2152         if (!area)
2153                 return -EINVAL;
2154 
2155         if (!(area->flags & VM_USERMAP))
2156                 return -EINVAL;
2157 
2158         if (kaddr + size > area->addr + area->size)
2159                 return -EINVAL;
2160 
2161         do {
2162                 struct page *page = vmalloc_to_page(kaddr);
2163                 int ret;
2164 
2165                 ret = vm_insert_page(vma, uaddr, page);
2166                 if (ret)
2167                         return ret;
2168 
2169                 uaddr += PAGE_SIZE;
2170                 kaddr += PAGE_SIZE;
2171                 size -= PAGE_SIZE;
2172         } while (size > 0);
2173 
2174         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
2175 
2176         return 0;
2177 }
2178 EXPORT_SYMBOL(remap_vmalloc_range_partial);
2179 
2180 /**
2181  *      remap_vmalloc_range  -  map vmalloc pages to userspace
2182  *      @vma:           vma to cover (map full range of vma)
2183  *      @addr:          vmalloc memory
2184  *      @pgoff:         number of pages into addr before first page to map
2185  *
2186  *      Returns:        0 for success, -Exxx on failure
2187  *
2188  *      This function checks that addr is a valid vmalloc'ed area, and
2189  *      that it is big enough to cover the vma. Will return failure if
2190  *      that criteria isn't met.
2191  *
2192  *      Similar to remap_pfn_range() (see mm/memory.c)
2193  */
2194 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
2195                                                 unsigned long pgoff)
2196 {
2197         return remap_vmalloc_range_partial(vma, vma->vm_start,
2198                                            addr + (pgoff << PAGE_SHIFT),
2199                                            vma->vm_end - vma->vm_start);
2200 }
2201 EXPORT_SYMBOL(remap_vmalloc_range);
2202 
2203 /*
2204  * Implement a stub for vmalloc_sync_all() if the architecture chose not to
2205  * have one.
2206  */
2207 void __weak vmalloc_sync_all(void)
2208 {
2209 }
2210 
2211 
2212 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
2213 {
2214         pte_t ***p = data;
2215 
2216         if (p) {
2217                 *(*p) = pte;
2218                 (*p)++;
2219         }
2220         return 0;
2221 }
2222 
2223 /**
2224  *      alloc_vm_area - allocate a range of kernel address space
2225  *      @size:          size of the area
2226  *      @ptes:          returns the PTEs for the address space
2227  *
2228  *      Returns:        NULL on failure, vm_struct on success
2229  *
2230  *      This function reserves a range of kernel address space, and
2231  *      allocates pagetables to map that range.  No actual mappings
2232  *      are created.
2233  *
2234  *      If @ptes is non-NULL, pointers to the PTEs (in init_mm)
2235  *      allocated for the VM area are returned.
2236  */
2237 struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
2238 {
2239         struct vm_struct *area;
2240 
2241         area = get_vm_area_caller(size, VM_IOREMAP,
2242                                 __builtin_return_address(0));
2243         if (area == NULL)
2244                 return NULL;
2245 
2246         /*
2247          * This ensures that page tables are constructed for this region
2248          * of kernel virtual address space and mapped into init_mm.
2249          */
2250         if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2251                                 size, f, ptes ? &ptes : NULL)) {
2252                 free_vm_area(area);
2253                 return NULL;
2254         }
2255 
2256         return area;
2257 }
2258 EXPORT_SYMBOL_GPL(alloc_vm_area);
2259 
2260 void free_vm_area(struct vm_struct *area)
2261 {
2262         struct vm_struct *ret;
2263         ret = remove_vm_area(area->addr);
2264         BUG_ON(ret != area);
2265         kfree(area);
2266 }
2267 EXPORT_SYMBOL_GPL(free_vm_area);
2268 
2269 #ifdef CONFIG_SMP
2270 static struct vmap_area *node_to_va(struct rb_node *n)
2271 {
2272         return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
2273 }
2274 
2275 /**
2276  * pvm_find_next_prev - find the next and prev vmap_area surrounding @end
2277  * @end: target address
2278  * @pnext: out arg for the next vmap_area
2279  * @pprev: out arg for the previous vmap_area
2280  *
2281  * Returns: %true if either or both of next and prev are found,
2282  *          %false if no vmap_area exists
2283  *
2284  * Find vmap_areas end addresses of which enclose @end.  ie. if not
2285  * NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
2286  */
2287 static bool pvm_find_next_prev(unsigned long end,
2288                                struct vmap_area **pnext,
2289                                struct vmap_area **pprev)
2290 {
2291         struct rb_node *n = vmap_area_root.rb_node;
2292         struct vmap_area *va = NULL;
2293 
2294         while (n) {
2295                 va = rb_entry(n, struct vmap_area, rb_node);
2296                 if (end < va->va_end)
2297                         n = n->rb_left;
2298                 else if (end > va->va_end)
2299                         n = n->rb_right;
2300                 else
2301                         break;
2302         }
2303 
2304         if (!va)
2305                 return false;
2306 
2307         if (va->va_end > end) {
2308                 *pnext = va;
2309                 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2310         } else {
2311                 *pprev = va;
2312                 *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
2313         }
2314         return true;
2315 }
2316 
2317 /**
2318  * pvm_determine_end - find the highest aligned address between two vmap_areas
2319  * @pnext: in/out arg for the next vmap_area
2320  * @pprev: in/out arg for the previous vmap_area
2321  * @align: alignment
2322  *
2323  * Returns: determined end address
2324  *
2325  * Find the highest aligned address between *@pnext and *@pprev below
2326  * VMALLOC_END.  *@pnext and *@pprev are adjusted so that the aligned
2327  * down address is between the end addresses of the two vmap_areas.
2328  *
2329  * Please note that the address returned by this function may fall
2330  * inside *@pnext vmap_area.  The caller is responsible for checking
2331  * that.
2332  */
2333 static unsigned long pvm_determine_end(struct vmap_area **pnext,
2334                                        struct vmap_area **pprev,
2335                                        unsigned long align)
2336 {
2337         const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2338         unsigned long addr;
2339 
2340         if (*pnext)
2341                 addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
2342         else
2343                 addr = vmalloc_end;
2344 
2345         while (*pprev && (*pprev)->va_end > addr) {
2346                 *pnext = *pprev;
2347                 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2348         }
2349 
2350         return addr;
2351 }
2352 
2353 /**
2354  * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
2355  * @offsets: array containing offset of each area
2356  * @sizes: array containing size of each area
2357  * @nr_vms: the number of areas to allocate
2358  * @align: alignment, all entries in @offsets and @sizes must be aligned to this
2359  *
2360  * Returns: kmalloc'd vm_struct pointer array pointing to allocated
2361  *          vm_structs on success, %NULL on failure
2362  *
2363  * Percpu allocator wants to use congruent vm areas so that it can
2364  * maintain the offsets among percpu areas.  This function allocates
2365  * congruent vmalloc areas for it with GFP_KERNEL.  These areas tend to
2366  * be scattered pretty far, distance between two areas easily going up
2367  * to gigabytes.  To avoid interacting with regular vmallocs, these
2368  * areas are allocated from top.
2369  *
2370  * Despite its complicated look, this allocator is rather simple.  It
2371  * does everything top-down and scans areas from the end looking for
2372  * matching slot.  While scanning, if any of the areas overlaps with
2373  * existing vmap_area, the base address is pulled down to fit the
2374  * area.  Scanning is repeated till all the areas fit and then all
2375  * necessary data structres are inserted and the result is returned.
2376  */
2377 struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
2378                                      const size_t *sizes, int nr_vms,
2379                                      size_t align)
2380 {
2381         const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
2382         const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2383         struct vmap_area **vas, *prev, *next;
2384         struct vm_struct **vms;
2385         int area, area2, last_area, term_area;
2386         unsigned long base, start, end, last_end;
2387         bool purged = false;
2388 
2389         /* verify parameters and allocate data structures */
2390         BUG_ON(offset_in_page(align) || !is_power_of_2(align));
2391         for (last_area = 0, area = 0; area < nr_vms; area++) {
2392                 start = offsets[area];
2393                 end = start + sizes[area];
2394 
2395                 /* is everything aligned properly? */
2396                 BUG_ON(!IS_ALIGNED(offsets[area], align));
2397                 BUG_ON(!IS_ALIGNED(sizes[area], align));
2398 
2399                 /* detect the area with the highest address */
2400                 if (start > offsets[last_area])
2401                         last_area = area;
2402 
2403                 for (area2 = 0; area2 < nr_vms; area2++) {
2404                         unsigned long start2 = offsets[area2];
2405                         unsigned long end2 = start2 + sizes[area2];
2406 
2407                         if (area2 == area)
2408                                 continue;
2409 
2410                         BUG_ON(start2 >= start && start2 < end);
2411                         BUG_ON(end2 <= end && end2 > start);
2412                 }
2413         }
2414         last_end = offsets[last_area] + sizes[last_area];
2415 
2416         if (vmalloc_end - vmalloc_start < last_end) {
2417                 WARN_ON(true);
2418                 return NULL;
2419         }
2420 
2421         vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
2422         vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
2423         if (!vas || !vms)
2424                 goto err_free2;
2425 
2426         for (area = 0; area < nr_vms; area++) {
2427                 vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL);
2428                 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
2429                 if (!vas[area] || !vms[area])
2430                         goto err_free;
2431         }
2432 retry:
2433         spin_lock(&vmap_area_lock);
2434 
2435         /* start scanning - we scan from the top, begin with the last area */
2436         area = term_area = last_area;
2437         start = offsets[area];
2438         end = start + sizes[area];
2439 
2440         if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
2441                 base = vmalloc_end - last_end;
2442                 goto found;
2443         }
2444         base = pvm_determine_end(&next, &prev, align) - end;
2445 
2446         while (true) {
2447                 BUG_ON(next && next->va_end <= base + end);
2448                 BUG_ON(prev && prev->va_end > base + end);
2449 
2450                 /*
2451                  * base might have underflowed, add last_end before
2452                  * comparing.
2453                  */
2454                 if (base + last_end < vmalloc_start + last_end) {
2455                         spin_unlock(&vmap_area_lock);
2456                         if (!purged) {
2457                                 purge_vmap_area_lazy();
2458                                 purged = true;
2459                                 goto retry;
2460                         }
2461                         goto err_free;
2462                 }
2463 
2464                 /*
2465                  * If next overlaps, move base downwards so that it's
2466                  * right below next and then recheck.
2467                  */
2468                 if (next && next->va_start < base + end) {
2469                         base = pvm_determine_end(&next, &prev, align) - end;
2470                         term_area = area;
2471                         continue;
2472                 }
2473 
2474                 /*
2475                  * If prev overlaps, shift down next and prev and move
2476                  * base so that it's right below new next and then
2477                  * recheck.
2478                  */
2479                 if (prev && prev->va_end > base + start)  {
2480                         next = prev;
2481                         prev = node_to_va(rb_prev(&next->rb_node));
2482                         base = pvm_determine_end(&next, &prev, align) - end;
2483                         term_area = area;
2484                         continue;
2485                 }
2486 
2487                 /*
2488                  * This area fits, move on to the previous one.  If
2489                  * the previous one is the terminal one, we're done.
2490                  */
2491                 area = (area + nr_vms - 1) % nr_vms;
2492                 if (area == term_area)
2493                         break;
2494                 start = offsets[area];
2495                 end = start + sizes[area];
2496                 pvm_find_next_prev(base + end, &next, &prev);
2497         }
2498 found:
2499         /* we've found a fitting base, insert all va's */
2500         for (area = 0; area < nr_vms; area++) {
2501                 struct vmap_area *va = vas[area];
2502 
2503                 va->va_start = base + offsets[area];
2504                 va->va_end = va->va_start + sizes[area];
2505                 __insert_vmap_area(va);
2506         }
2507 
2508         vmap_area_pcpu_hole = base + offsets[last_area];
2509 
2510         spin_unlock(&vmap_area_lock);
2511 
2512         /* insert all vm's */
2513         for (area = 0; area < nr_vms; area++)
2514                 setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
2515                                  pcpu_get_vm_areas);
2516 
2517         kfree(vas);
2518         return vms;
2519 
2520 err_free:
2521         for (area = 0; area < nr_vms; area++) {
2522                 kfree(vas[area]);
2523                 kfree(vms[area]);
2524         }
2525 err_free2:
2526         kfree(vas);
2527         kfree(vms);
2528         return NULL;
2529 }
2530 
2531 /**
2532  * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
2533  * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
2534  * @nr_vms: the number of allocated areas
2535  *
2536  * Free vm_structs and the array allocated by pcpu_get_vm_areas().
2537  */
2538 void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
2539 {
2540         int i;
2541 
2542         for (i = 0; i < nr_vms; i++)
2543                 free_vm_area(vms[i]);
2544         kfree(vms);
2545 }
2546 #endif  /* CONFIG_SMP */
2547 
2548 #ifdef CONFIG_PROC_FS
2549 static void *s_start(struct seq_file *m, loff_t *pos)
2550         __acquires(&vmap_area_lock)
2551 {
2552         loff_t n = *pos;
2553         struct vmap_area *va;
2554 
2555         spin_lock(&vmap_area_lock);
2556         va = list_first_entry(&vmap_area_list, typeof(*va), list);
2557         while (n > 0 && &va->list != &vmap_area_list) {
2558                 n--;
2559                 va = list_next_entry(va, list);
2560         }
2561         if (!n && &va->list != &vmap_area_list)
2562                 return va;
2563 
2564         return NULL;
2565 
2566 }
2567 
2568 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2569 {
2570         struct vmap_area *va = p, *next;
2571 
2572         ++*pos;
2573         next = list_next_entry(va, list);
2574         if (&next->list != &vmap_area_list)
2575                 return next;
2576 
2577         return NULL;
2578 }
2579 
2580 static void s_stop(struct seq_file *m, void *p)
2581         __releases(&vmap_area_lock)
2582 {
2583         spin_unlock(&vmap_area_lock);
2584 }
2585 
2586 static void show_numa_info(struct seq_file *m, struct vm_struct *v)
2587 {
2588         if (IS_ENABLED(CONFIG_NUMA)) {
2589                 unsigned int nr, *counters = m->private;
2590 
2591                 if (!counters)
2592                         return;
2593 
2594                 if (v->flags & VM_UNINITIALIZED)
2595                         return;
2596                 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
2597                 smp_rmb();
2598 
2599                 memset(counters, 0, nr_node_ids * sizeof(unsigned int));
2600 
2601                 for (nr = 0; nr < v->nr_pages; nr++)
2602                         counters[page_to_nid(v->pages[nr])]++;
2603 
2604                 for_each_node_state(nr, N_HIGH_MEMORY)
2605                         if (counters[nr])
2606                                 seq_printf(m, " N%u=%u", nr, counters[nr]);
2607         }
2608 }
2609 
2610 static int s_show(struct seq_file *m, void *p)
2611 {
2612         struct vmap_area *va = p;
2613         struct vm_struct *v;
2614 
2615         /*
2616          * s_show can encounter race with remove_vm_area, !VM_VM_AREA on
2617          * behalf of vmap area is being tear down or vm_map_ram allocation.
2618          */
2619         if (!(va->flags & VM_VM_AREA))
2620                 return 0;
2621 
2622         v = va->vm;
2623 
2624         seq_printf(m, "0x%pK-0x%pK %7ld",
2625                 v->addr, v->addr + v->size, v->size);
2626 
2627         if (v->caller)
2628                 seq_printf(m, " %pS", v->caller);
2629 
2630         if (v->nr_pages)
2631                 seq_printf(m, " pages=%d", v->nr_pages);
2632 
2633         if (v->phys_addr)
2634                 seq_printf(m, " phys=%llx", (unsigned long long)v->phys_addr);
2635 
2636         if (v->flags & VM_IOREMAP)
2637                 seq_puts(m, " ioremap");
2638 
2639         if (v->flags & VM_ALLOC)
2640                 seq_puts(m, " vmalloc");
2641 
2642         if (v->flags & VM_MAP)
2643                 seq_puts(m, " vmap");
2644 
2645         if (v->flags & VM_USERMAP)
2646                 seq_puts(m, " user");
2647 
2648         if (is_vmalloc_addr(v->pages))
2649                 seq_puts(m, " vpages");
2650 
2651         show_numa_info(m, v);
2652         seq_putc(m, '\n');
2653         return 0;
2654 }
2655 
2656 static const struct seq_operations vmalloc_op = {
2657         .start = s_start,
2658         .next = s_next,
2659         .stop = s_stop,
2660         .show = s_show,
2661 };
2662 
2663 static int vmalloc_open(struct inode *inode, struct file *file)
2664 {
2665         if (IS_ENABLED(CONFIG_NUMA))
2666                 return seq_open_private(file, &vmalloc_op,
2667                                         nr_node_ids * sizeof(unsigned int));
2668         else
2669                 return seq_open(file, &vmalloc_op);
2670 }
2671 
2672 static const struct file_operations proc_vmalloc_operations = {
2673         .open           = vmalloc_open,
2674         .read           = seq_read,
2675         .llseek         = seq_lseek,
2676         .release        = seq_release_private,
2677 };
2678 
2679 static int __init proc_vmalloc_init(void)
2680 {
2681         proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
2682         return 0;
2683 }
2684 module_init(proc_vmalloc_init);
2685 
2686 #endif
2687 
2688 

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