linux/mm/vmalloc.c
<<
>>
Prefs
   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/llist.h>
  31#include <asm/uaccess.h>
  32#include <asm/tlbflush.h>
  33#include <asm/shmparam.h>
  34
  35struct vfree_deferred {
  36        struct llist_head list;
  37        struct work_struct wq;
  38};
  39static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
  40
  41static void __vunmap(const void *, int);
  42
  43static void free_work(struct work_struct *w)
  44{
  45        struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
  46        struct llist_node *llnode = llist_del_all(&p->list);
  47        while (llnode) {
  48                void *p = llnode;
  49                llnode = llist_next(llnode);
  50                __vunmap(p, 1);
  51        }
  52}
  53
  54/*** Page table manipulation functions ***/
  55
  56static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
  57{
  58        pte_t *pte;
  59
  60        pte = pte_offset_kernel(pmd, addr);
  61        do {
  62                pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
  63                WARN_ON(!pte_none(ptent) && !pte_present(ptent));
  64        } while (pte++, addr += PAGE_SIZE, addr != end);
  65}
  66
  67static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
  68{
  69        pmd_t *pmd;
  70        unsigned long next;
  71
  72        pmd = pmd_offset(pud, addr);
  73        do {
  74                next = pmd_addr_end(addr, end);
  75                if (pmd_none_or_clear_bad(pmd))
  76                        continue;
  77                vunmap_pte_range(pmd, addr, next);
  78        } while (pmd++, addr = next, addr != end);
  79}
  80
  81static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
  82{
  83        pud_t *pud;
  84        unsigned long next;
  85
  86        pud = pud_offset(pgd, addr);
  87        do {
  88                next = pud_addr_end(addr, end);
  89                if (pud_none_or_clear_bad(pud))
  90                        continue;
  91                vunmap_pmd_range(pud, addr, next);
  92        } while (pud++, addr = next, addr != end);
  93}
  94
  95static void vunmap_page_range(unsigned long addr, unsigned long end)
  96{
  97        pgd_t *pgd;
  98        unsigned long next;
  99
 100        BUG_ON(addr >= end);
 101        pgd = pgd_offset_k(addr);
 102        do {
 103                next = pgd_addr_end(addr, end);
 104                if (pgd_none_or_clear_bad(pgd))
 105                        continue;
 106                vunmap_pud_range(pgd, addr, next);
 107        } while (pgd++, addr = next, addr != end);
 108}
 109
 110static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
 111                unsigned long end, pgprot_t prot, struct page **pages, int *nr)
 112{
 113        pte_t *pte;
 114
 115        /*
 116         * nr is a running index into the array which helps higher level
 117         * callers keep track of where we're up to.
 118         */
 119
 120        pte = pte_alloc_kernel(pmd, addr);
 121        if (!pte)
 122                return -ENOMEM;
 123        do {
 124                struct page *page = pages[*nr];
 125
 126                if (WARN_ON(!pte_none(*pte)))
 127                        return -EBUSY;
 128                if (WARN_ON(!page))
 129                        return -ENOMEM;
 130                set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
 131                (*nr)++;
 132        } while (pte++, addr += PAGE_SIZE, addr != end);
 133        return 0;
 134}
 135
 136static int vmap_pmd_range(pud_t *pud, unsigned long addr,
 137                unsigned long end, pgprot_t prot, struct page **pages, int *nr)
 138{
 139        pmd_t *pmd;
 140        unsigned long next;
 141
 142        pmd = pmd_alloc(&init_mm, pud, addr);
 143        if (!pmd)
 144                return -ENOMEM;
 145        do {
 146                next = pmd_addr_end(addr, end);
 147                if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
 148                        return -ENOMEM;
 149        } while (pmd++, addr = next, addr != end);
 150        return 0;
 151}
 152
 153static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
 154                unsigned long end, pgprot_t prot, struct page **pages, int *nr)
 155{
 156        pud_t *pud;
 157        unsigned long next;
 158
 159        pud = pud_alloc(&init_mm, pgd, addr);
 160        if (!pud)
 161                return -ENOMEM;
 162        do {
 163                next = pud_addr_end(addr, end);
 164                if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
 165                        return -ENOMEM;
 166        } while (pud++, addr = next, addr != end);
 167        return 0;
 168}
 169
 170/*
 171 * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
 172 * will have pfns corresponding to the "pages" array.
 173 *
 174 * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
 175 */
 176static int vmap_page_range_noflush(unsigned long start, unsigned long end,
 177                                   pgprot_t prot, struct page **pages)
 178{
 179        pgd_t *pgd;
 180        unsigned long next;
 181        unsigned long addr = start;
 182        int err = 0;
 183        int nr = 0;
 184
 185        BUG_ON(addr >= end);
 186        pgd = pgd_offset_k(addr);
 187        do {
 188                next = pgd_addr_end(addr, end);
 189                err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
 190                if (err)
 191                        return err;
 192        } while (pgd++, addr = next, addr != end);
 193
 194        return nr;
 195}
 196
 197static int vmap_page_range(unsigned long start, unsigned long end,
 198                           pgprot_t prot, struct page **pages)
 199{
 200        int ret;
 201
 202        ret = vmap_page_range_noflush(start, end, prot, pages);
 203        flush_cache_vmap(start, end);
 204        return ret;
 205}
 206
 207int is_vmalloc_or_module_addr(const void *x)
 208{
 209        /*
 210         * ARM, x86-64 and sparc64 put modules in a special place,
 211         * and fall back on vmalloc() if that fails. Others
 212         * just put it in the vmalloc space.
 213         */
 214#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
 215        unsigned long addr = (unsigned long)x;
 216        if (addr >= MODULES_VADDR && addr < MODULES_END)
 217                return 1;
 218#endif
 219        return is_vmalloc_addr(x);
 220}
 221
 222/*
 223 * Walk a vmap address to the struct page it maps.
 224 */
 225struct page *vmalloc_to_page(const void *vmalloc_addr)
 226{
 227        unsigned long addr = (unsigned long) vmalloc_addr;
 228        struct page *page = NULL;
 229        pgd_t *pgd = pgd_offset_k(addr);
 230
 231        /*
 232         * XXX we might need to change this if we add VIRTUAL_BUG_ON for
 233         * architectures that do not vmalloc module space
 234         */
 235        VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
 236
 237        if (!pgd_none(*pgd)) {
 238                pud_t *pud = pud_offset(pgd, addr);
 239                if (!pud_none(*pud)) {
 240                        pmd_t *pmd = pmd_offset(pud, addr);
 241                        if (!pmd_none(*pmd)) {
 242                                pte_t *ptep, pte;
 243
 244                                ptep = pte_offset_map(pmd, addr);
 245                                pte = *ptep;
 246                                if (pte_present(pte))
 247                                        page = pte_page(pte);
 248                                pte_unmap(ptep);
 249                        }
 250                }
 251        }
 252        return page;
 253}
 254EXPORT_SYMBOL(vmalloc_to_page);
 255
 256/*
 257 * Map a vmalloc()-space virtual address to the physical page frame number.
 258 */
 259unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
 260{
 261        return page_to_pfn(vmalloc_to_page(vmalloc_addr));
 262}
 263EXPORT_SYMBOL(vmalloc_to_pfn);
 264
 265
 266/*** Global kva allocator ***/
 267
 268#define VM_LAZY_FREE    0x01
 269#define VM_LAZY_FREEING 0x02
 270#define VM_VM_AREA      0x04
 271
 272static DEFINE_SPINLOCK(vmap_area_lock);
 273/* Export for kexec only */
 274LIST_HEAD(vmap_area_list);
 275static struct rb_root vmap_area_root = RB_ROOT;
 276
 277/* The vmap cache globals are protected by vmap_area_lock */
 278static struct rb_node *free_vmap_cache;
 279static unsigned long cached_hole_size;
 280static unsigned long cached_vstart;
 281static unsigned long cached_align;
 282
 283static unsigned long vmap_area_pcpu_hole;
 284
 285static struct vmap_area *__find_vmap_area(unsigned long addr)
 286{
 287        struct rb_node *n = vmap_area_root.rb_node;
 288
 289        while (n) {
 290                struct vmap_area *va;
 291
 292                va = rb_entry(n, struct vmap_area, rb_node);
 293                if (addr < va->va_start)
 294                        n = n->rb_left;
 295                else if (addr > va->va_start)
 296                        n = n->rb_right;
 297                else
 298                        return va;
 299        }
 300
 301        return NULL;
 302}
 303
 304static void __insert_vmap_area(struct vmap_area *va)
 305{
 306        struct rb_node **p = &vmap_area_root.rb_node;
 307        struct rb_node *parent = NULL;
 308        struct rb_node *tmp;
 309
 310        while (*p) {
 311                struct vmap_area *tmp_va;
 312
 313                parent = *p;
 314                tmp_va = rb_entry(parent, struct vmap_area, rb_node);
 315                if (va->va_start < tmp_va->va_end)
 316                        p = &(*p)->rb_left;
 317                else if (va->va_end > tmp_va->va_start)
 318                        p = &(*p)->rb_right;
 319                else
 320                        BUG();
 321        }
 322
 323        rb_link_node(&va->rb_node, parent, p);
 324        rb_insert_color(&va->rb_node, &vmap_area_root);
 325
 326        /* address-sort this list */
 327        tmp = rb_prev(&va->rb_node);
 328        if (tmp) {
 329                struct vmap_area *prev;
 330                prev = rb_entry(tmp, struct vmap_area, rb_node);
 331                list_add_rcu(&va->list, &prev->list);
 332        } else
 333                list_add_rcu(&va->list, &vmap_area_list);
 334}
 335
 336static void purge_vmap_area_lazy(void);
 337
 338/*
 339 * Allocate a region of KVA of the specified size and alignment, within the
 340 * vstart and vend.
 341 */
 342static struct vmap_area *alloc_vmap_area(unsigned long size,
 343                                unsigned long align,
 344                                unsigned long vstart, unsigned long vend,
 345                                int node, gfp_t gfp_mask)
 346{
 347        struct vmap_area *va;
 348        struct rb_node *n;
 349        unsigned long addr;
 350        int purged = 0;
 351        struct vmap_area *first;
 352
 353        BUG_ON(!size);
 354        BUG_ON(size & ~PAGE_MASK);
 355        BUG_ON(!is_power_of_2(align));
 356
 357        va = kmalloc_node(sizeof(struct vmap_area),
 358                        gfp_mask & GFP_RECLAIM_MASK, node);
 359        if (unlikely(!va))
 360                return ERR_PTR(-ENOMEM);
 361
 362retry:
 363        spin_lock(&vmap_area_lock);
 364        /*
 365         * Invalidate cache if we have more permissive parameters.
 366         * cached_hole_size notes the largest hole noticed _below_
 367         * the vmap_area cached in free_vmap_cache: if size fits
 368         * into that hole, we want to scan from vstart to reuse
 369         * the hole instead of allocating above free_vmap_cache.
 370         * Note that __free_vmap_area may update free_vmap_cache
 371         * without updating cached_hole_size or cached_align.
 372         */
 373        if (!free_vmap_cache ||
 374                        size < cached_hole_size ||
 375                        vstart < cached_vstart ||
 376                        align < cached_align) {
 377nocache:
 378                cached_hole_size = 0;
 379                free_vmap_cache = NULL;
 380        }
 381        /* record if we encounter less permissive parameters */
 382        cached_vstart = vstart;
 383        cached_align = align;
 384
 385        /* find starting point for our search */
 386        if (free_vmap_cache) {
 387                first = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
 388                addr = ALIGN(first->va_end, align);
 389                if (addr < vstart)
 390                        goto nocache;
 391                if (addr + size - 1 < addr)
 392                        goto overflow;
 393
 394        } else {
 395                addr = ALIGN(vstart, align);
 396                if (addr + size - 1 < addr)
 397                        goto overflow;
 398
 399                n = vmap_area_root.rb_node;
 400                first = NULL;
 401
 402                while (n) {
 403                        struct vmap_area *tmp;
 404                        tmp = rb_entry(n, struct vmap_area, rb_node);
 405                        if (tmp->va_end >= addr) {
 406                                first = tmp;
 407                                if (tmp->va_start <= addr)
 408                                        break;
 409                                n = n->rb_left;
 410                        } else
 411                                n = n->rb_right;
 412                }
 413
 414                if (!first)
 415                        goto found;
 416        }
 417
 418        /* from the starting point, walk areas until a suitable hole is found */
 419        while (addr + size > first->va_start && addr + size <= vend) {
 420                if (addr + cached_hole_size < first->va_start)
 421                        cached_hole_size = first->va_start - addr;
 422                addr = ALIGN(first->va_end, align);
 423                if (addr + size - 1 < addr)
 424                        goto overflow;
 425
 426                if (list_is_last(&first->list, &vmap_area_list))
 427                        goto found;
 428
 429                first = list_entry(first->list.next,
 430                                struct vmap_area, list);
 431        }
 432
 433found:
 434        if (addr + size > vend)
 435                goto overflow;
 436
 437        va->va_start = addr;
 438        va->va_end = addr + size;
 439        va->flags = 0;
 440        __insert_vmap_area(va);
 441        free_vmap_cache = &va->rb_node;
 442        spin_unlock(&vmap_area_lock);
 443
 444        BUG_ON(va->va_start & (align-1));
 445        BUG_ON(va->va_start < vstart);
 446        BUG_ON(va->va_end > vend);
 447
 448        return va;
 449
 450overflow:
 451        spin_unlock(&vmap_area_lock);
 452        if (!purged) {
 453                purge_vmap_area_lazy();
 454                purged = 1;
 455                goto retry;
 456        }
 457        if (printk_ratelimit())
 458                printk(KERN_WARNING
 459                        "vmap allocation for size %lu failed: "
 460                        "use vmalloc=<size> to increase size.\n", size);
 461        kfree(va);
 462        return ERR_PTR(-EBUSY);
 463}
 464
 465static void __free_vmap_area(struct vmap_area *va)
 466{
 467        BUG_ON(RB_EMPTY_NODE(&va->rb_node));
 468
 469        if (free_vmap_cache) {
 470                if (va->va_end < cached_vstart) {
 471                        free_vmap_cache = NULL;
 472                } else {
 473                        struct vmap_area *cache;
 474                        cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
 475                        if (va->va_start <= cache->va_start) {
 476                                free_vmap_cache = rb_prev(&va->rb_node);
 477                                /*
 478                                 * We don't try to update cached_hole_size or
 479                                 * cached_align, but it won't go very wrong.
 480                                 */
 481                        }
 482                }
 483        }
 484        rb_erase(&va->rb_node, &vmap_area_root);
 485        RB_CLEAR_NODE(&va->rb_node);
 486        list_del_rcu(&va->list);
 487
 488        /*
 489         * Track the highest possible candidate for pcpu area
 490         * allocation.  Areas outside of vmalloc area can be returned
 491         * here too, consider only end addresses which fall inside
 492         * vmalloc area proper.
 493         */
 494        if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
 495                vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
 496
 497        kfree_rcu(va, rcu_head);
 498}
 499
 500/*
 501 * Free a region of KVA allocated by alloc_vmap_area
 502 */
 503static void free_vmap_area(struct vmap_area *va)
 504{
 505        spin_lock(&vmap_area_lock);
 506        __free_vmap_area(va);
 507        spin_unlock(&vmap_area_lock);
 508}
 509
 510/*
 511 * Clear the pagetable entries of a given vmap_area
 512 */
 513static void unmap_vmap_area(struct vmap_area *va)
 514{
 515        vunmap_page_range(va->va_start, va->va_end);
 516}
 517
 518static void vmap_debug_free_range(unsigned long start, unsigned long end)
 519{
 520        /*
 521         * Unmap page tables and force a TLB flush immediately if
 522         * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free
 523         * bugs similarly to those in linear kernel virtual address
 524         * space after a page has been freed.
 525         *
 526         * All the lazy freeing logic is still retained, in order to
 527         * minimise intrusiveness of this debugging feature.
 528         *
 529         * This is going to be *slow* (linear kernel virtual address
 530         * debugging doesn't do a broadcast TLB flush so it is a lot
 531         * faster).
 532         */
 533#ifdef CONFIG_DEBUG_PAGEALLOC
 534        vunmap_page_range(start, end);
 535        flush_tlb_kernel_range(start, end);
 536#endif
 537}
 538
 539/*
 540 * lazy_max_pages is the maximum amount of virtual address space we gather up
 541 * before attempting to purge with a TLB flush.
 542 *
 543 * There is a tradeoff here: a larger number will cover more kernel page tables
 544 * and take slightly longer to purge, but it will linearly reduce the number of
 545 * global TLB flushes that must be performed. It would seem natural to scale
 546 * this number up linearly with the number of CPUs (because vmapping activity
 547 * could also scale linearly with the number of CPUs), however it is likely
 548 * that in practice, workloads might be constrained in other ways that mean
 549 * vmap activity will not scale linearly with CPUs. Also, I want to be
 550 * conservative and not introduce a big latency on huge systems, so go with
 551 * a less aggressive log scale. It will still be an improvement over the old
 552 * code, and it will be simple to change the scale factor if we find that it
 553 * becomes a problem on bigger systems.
 554 */
 555static unsigned long lazy_max_pages(void)
 556{
 557        unsigned int log;
 558
 559        log = fls(num_online_cpus());
 560
 561        return log * (32UL * 1024 * 1024 / PAGE_SIZE);
 562}
 563
 564static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
 565
 566/* for per-CPU blocks */
 567static void purge_fragmented_blocks_allcpus(void);
 568
 569/*
 570 * called before a call to iounmap() if the caller wants vm_area_struct's
 571 * immediately freed.
 572 */
 573void set_iounmap_nonlazy(void)
 574{
 575        atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
 576}
 577
 578/*
 579 * Purges all lazily-freed vmap areas.
 580 *
 581 * If sync is 0 then don't purge if there is already a purge in progress.
 582 * If force_flush is 1, then flush kernel TLBs between *start and *end even
 583 * if we found no lazy vmap areas to unmap (callers can use this to optimise
 584 * their own TLB flushing).
 585 * Returns with *start = min(*start, lowest purged address)
 586 *              *end = max(*end, highest purged address)
 587 */
 588static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
 589                                        int sync, int force_flush)
 590{
 591        static DEFINE_SPINLOCK(purge_lock);
 592        LIST_HEAD(valist);
 593        struct vmap_area *va;
 594        struct vmap_area *n_va;
 595        int nr = 0;
 596
 597        /*
 598         * If sync is 0 but force_flush is 1, we'll go sync anyway but callers
 599         * should not expect such behaviour. This just simplifies locking for
 600         * the case that isn't actually used at the moment anyway.
 601         */
 602        if (!sync && !force_flush) {
 603                if (!spin_trylock(&purge_lock))
 604                        return;
 605        } else
 606                spin_lock(&purge_lock);
 607
 608        if (sync)
 609                purge_fragmented_blocks_allcpus();
 610
 611        rcu_read_lock();
 612        list_for_each_entry_rcu(va, &vmap_area_list, list) {
 613                if (va->flags & VM_LAZY_FREE) {
 614                        if (va->va_start < *start)
 615                                *start = va->va_start;
 616                        if (va->va_end > *end)
 617                                *end = va->va_end;
 618                        nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
 619                        list_add_tail(&va->purge_list, &valist);
 620                        va->flags |= VM_LAZY_FREEING;
 621                        va->flags &= ~VM_LAZY_FREE;
 622                }
 623        }
 624        rcu_read_unlock();
 625
 626        if (nr)
 627                atomic_sub(nr, &vmap_lazy_nr);
 628
 629        if (nr || force_flush)
 630                flush_tlb_kernel_range(*start, *end);
 631
 632        if (nr) {
 633                spin_lock(&vmap_area_lock);
 634                list_for_each_entry_safe(va, n_va, &valist, purge_list)
 635                        __free_vmap_area(va);
 636                spin_unlock(&vmap_area_lock);
 637        }
 638        spin_unlock(&purge_lock);
 639}
 640
 641/*
 642 * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
 643 * is already purging.
 644 */
 645static void try_purge_vmap_area_lazy(void)
 646{
 647        unsigned long start = ULONG_MAX, end = 0;
 648
 649        __purge_vmap_area_lazy(&start, &end, 0, 0);
 650}
 651
 652/*
 653 * Kick off a purge of the outstanding lazy areas.
 654 */
 655static void purge_vmap_area_lazy(void)
 656{
 657        unsigned long start = ULONG_MAX, end = 0;
 658
 659        __purge_vmap_area_lazy(&start, &end, 1, 0);
 660}
 661
 662/*
 663 * Free a vmap area, caller ensuring that the area has been unmapped
 664 * and flush_cache_vunmap had been called for the correct range
 665 * previously.
 666 */
 667static void free_vmap_area_noflush(struct vmap_area *va)
 668{
 669        va->flags |= VM_LAZY_FREE;
 670        atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr);
 671        if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages()))
 672                try_purge_vmap_area_lazy();
 673}
 674
 675/*
 676 * Free and unmap a vmap area, caller ensuring flush_cache_vunmap had been
 677 * called for the correct range previously.
 678 */
 679static void free_unmap_vmap_area_noflush(struct vmap_area *va)
 680{
 681        unmap_vmap_area(va);
 682        free_vmap_area_noflush(va);
 683}
 684
 685/*
 686 * Free and unmap a vmap area
 687 */
 688static void free_unmap_vmap_area(struct vmap_area *va)
 689{
 690        flush_cache_vunmap(va->va_start, va->va_end);
 691        free_unmap_vmap_area_noflush(va);
 692}
 693
 694static struct vmap_area *find_vmap_area(unsigned long addr)
 695{
 696        struct vmap_area *va;
 697
 698        spin_lock(&vmap_area_lock);
 699        va = __find_vmap_area(addr);
 700        spin_unlock(&vmap_area_lock);
 701
 702        return va;
 703}
 704
 705static void free_unmap_vmap_area_addr(unsigned long addr)
 706{
 707        struct vmap_area *va;
 708
 709        va = find_vmap_area(addr);
 710        BUG_ON(!va);
 711        free_unmap_vmap_area(va);
 712}
 713
 714
 715/*** Per cpu kva allocator ***/
 716
 717/*
 718 * vmap space is limited especially on 32 bit architectures. Ensure there is
 719 * room for at least 16 percpu vmap blocks per CPU.
 720 */
 721/*
 722 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
 723 * to #define VMALLOC_SPACE             (VMALLOC_END-VMALLOC_START). Guess
 724 * instead (we just need a rough idea)
 725 */
 726#if BITS_PER_LONG == 32
 727#define VMALLOC_SPACE           (128UL*1024*1024)
 728#else
 729#define VMALLOC_SPACE           (128UL*1024*1024*1024)
 730#endif
 731
 732#define VMALLOC_PAGES           (VMALLOC_SPACE / PAGE_SIZE)
 733#define VMAP_MAX_ALLOC          BITS_PER_LONG   /* 256K with 4K pages */
 734#define VMAP_BBMAP_BITS_MAX     1024    /* 4MB with 4K pages */
 735#define VMAP_BBMAP_BITS_MIN     (VMAP_MAX_ALLOC*2)
 736#define VMAP_MIN(x, y)          ((x) < (y) ? (x) : (y)) /* can't use min() */
 737#define VMAP_MAX(x, y)          ((x) > (y) ? (x) : (y)) /* can't use max() */
 738#define VMAP_BBMAP_BITS         \
 739                VMAP_MIN(VMAP_BBMAP_BITS_MAX,   \
 740                VMAP_MAX(VMAP_BBMAP_BITS_MIN,   \
 741                        VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
 742
 743#define VMAP_BLOCK_SIZE         (VMAP_BBMAP_BITS * PAGE_SIZE)
 744
 745static bool vmap_initialized __read_mostly = false;
 746
 747struct vmap_block_queue {
 748        spinlock_t lock;
 749        struct list_head free;
 750};
 751
 752struct vmap_block {
 753        spinlock_t lock;
 754        struct vmap_area *va;
 755        struct vmap_block_queue *vbq;
 756        unsigned long free, dirty;
 757        DECLARE_BITMAP(alloc_map, VMAP_BBMAP_BITS);
 758        DECLARE_BITMAP(dirty_map, VMAP_BBMAP_BITS);
 759        struct list_head free_list;
 760        struct rcu_head rcu_head;
 761        struct list_head purge;
 762};
 763
 764/* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
 765static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
 766
 767/*
 768 * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
 769 * in the free path. Could get rid of this if we change the API to return a
 770 * "cookie" from alloc, to be passed to free. But no big deal yet.
 771 */
 772static DEFINE_SPINLOCK(vmap_block_tree_lock);
 773static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
 774
 775/*
 776 * We should probably have a fallback mechanism to allocate virtual memory
 777 * out of partially filled vmap blocks. However vmap block sizing should be
 778 * fairly reasonable according to the vmalloc size, so it shouldn't be a
 779 * big problem.
 780 */
 781
 782static unsigned long addr_to_vb_idx(unsigned long addr)
 783{
 784        addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
 785        addr /= VMAP_BLOCK_SIZE;
 786        return addr;
 787}
 788
 789static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
 790{
 791        struct vmap_block_queue *vbq;
 792        struct vmap_block *vb;
 793        struct vmap_area *va;
 794        unsigned long vb_idx;
 795        int node, err;
 796
 797        node = numa_node_id();
 798
 799        vb = kmalloc_node(sizeof(struct vmap_block),
 800                        gfp_mask & GFP_RECLAIM_MASK, node);
 801        if (unlikely(!vb))
 802                return ERR_PTR(-ENOMEM);
 803
 804        va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
 805                                        VMALLOC_START, VMALLOC_END,
 806                                        node, gfp_mask);
 807        if (IS_ERR(va)) {
 808                kfree(vb);
 809                return ERR_CAST(va);
 810        }
 811
 812        err = radix_tree_preload(gfp_mask);
 813        if (unlikely(err)) {
 814                kfree(vb);
 815                free_vmap_area(va);
 816                return ERR_PTR(err);
 817        }
 818
 819        spin_lock_init(&vb->lock);
 820        vb->va = va;
 821        vb->free = VMAP_BBMAP_BITS;
 822        vb->dirty = 0;
 823        bitmap_zero(vb->alloc_map, VMAP_BBMAP_BITS);
 824        bitmap_zero(vb->dirty_map, VMAP_BBMAP_BITS);
 825        INIT_LIST_HEAD(&vb->free_list);
 826
 827        vb_idx = addr_to_vb_idx(va->va_start);
 828        spin_lock(&vmap_block_tree_lock);
 829        err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
 830        spin_unlock(&vmap_block_tree_lock);
 831        BUG_ON(err);
 832        radix_tree_preload_end();
 833
 834        vbq = &get_cpu_var(vmap_block_queue);
 835        vb->vbq = vbq;
 836        spin_lock(&vbq->lock);
 837        list_add_rcu(&vb->free_list, &vbq->free);
 838        spin_unlock(&vbq->lock);
 839        put_cpu_var(vmap_block_queue);
 840
 841        return vb;
 842}
 843
 844static void free_vmap_block(struct vmap_block *vb)
 845{
 846        struct vmap_block *tmp;
 847        unsigned long vb_idx;
 848
 849        vb_idx = addr_to_vb_idx(vb->va->va_start);
 850        spin_lock(&vmap_block_tree_lock);
 851        tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
 852        spin_unlock(&vmap_block_tree_lock);
 853        BUG_ON(tmp != vb);
 854
 855        free_vmap_area_noflush(vb->va);
 856        kfree_rcu(vb, rcu_head);
 857}
 858
 859static void purge_fragmented_blocks(int cpu)
 860{
 861        LIST_HEAD(purge);
 862        struct vmap_block *vb;
 863        struct vmap_block *n_vb;
 864        struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
 865
 866        rcu_read_lock();
 867        list_for_each_entry_rcu(vb, &vbq->free, free_list) {
 868
 869                if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
 870                        continue;
 871
 872                spin_lock(&vb->lock);
 873                if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
 874                        vb->free = 0; /* prevent further allocs after releasing lock */
 875                        vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
 876                        bitmap_fill(vb->alloc_map, VMAP_BBMAP_BITS);
 877                        bitmap_fill(vb->dirty_map, VMAP_BBMAP_BITS);
 878                        spin_lock(&vbq->lock);
 879                        list_del_rcu(&vb->free_list);
 880                        spin_unlock(&vbq->lock);
 881                        spin_unlock(&vb->lock);
 882                        list_add_tail(&vb->purge, &purge);
 883                } else
 884                        spin_unlock(&vb->lock);
 885        }
 886        rcu_read_unlock();
 887
 888        list_for_each_entry_safe(vb, n_vb, &purge, purge) {
 889                list_del(&vb->purge);
 890                free_vmap_block(vb);
 891        }
 892}
 893
 894static void purge_fragmented_blocks_thiscpu(void)
 895{
 896        purge_fragmented_blocks(smp_processor_id());
 897}
 898
 899static void purge_fragmented_blocks_allcpus(void)
 900{
 901        int cpu;
 902
 903        for_each_possible_cpu(cpu)
 904                purge_fragmented_blocks(cpu);
 905}
 906
 907static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
 908{
 909        struct vmap_block_queue *vbq;
 910        struct vmap_block *vb;
 911        unsigned long addr = 0;
 912        unsigned int order;
 913        int purge = 0;
 914
 915        BUG_ON(size & ~PAGE_MASK);
 916        BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
 917        if (WARN_ON(size == 0)) {
 918                /*
 919                 * Allocating 0 bytes isn't what caller wants since
 920                 * get_order(0) returns funny result. Just warn and terminate
 921                 * early.
 922                 */
 923                return NULL;
 924        }
 925        order = get_order(size);
 926
 927again:
 928        rcu_read_lock();
 929        vbq = &get_cpu_var(vmap_block_queue);
 930        list_for_each_entry_rcu(vb, &vbq->free, free_list) {
 931                int i;
 932
 933                spin_lock(&vb->lock);
 934                if (vb->free < 1UL << order)
 935                        goto next;
 936
 937                i = bitmap_find_free_region(vb->alloc_map,
 938                                                VMAP_BBMAP_BITS, order);
 939
 940                if (i < 0) {
 941                        if (vb->free + vb->dirty == VMAP_BBMAP_BITS) {
 942                                /* fragmented and no outstanding allocations */
 943                                BUG_ON(vb->dirty != VMAP_BBMAP_BITS);
 944                                purge = 1;
 945                        }
 946                        goto next;
 947                }
 948                addr = vb->va->va_start + (i << PAGE_SHIFT);
 949                BUG_ON(addr_to_vb_idx(addr) !=
 950                                addr_to_vb_idx(vb->va->va_start));
 951                vb->free -= 1UL << order;
 952                if (vb->free == 0) {
 953                        spin_lock(&vbq->lock);
 954                        list_del_rcu(&vb->free_list);
 955                        spin_unlock(&vbq->lock);
 956                }
 957                spin_unlock(&vb->lock);
 958                break;
 959next:
 960                spin_unlock(&vb->lock);
 961        }
 962
 963        if (purge)
 964                purge_fragmented_blocks_thiscpu();
 965
 966        put_cpu_var(vmap_block_queue);
 967        rcu_read_unlock();
 968
 969        if (!addr) {
 970                vb = new_vmap_block(gfp_mask);
 971                if (IS_ERR(vb))
 972                        return vb;
 973                goto again;
 974        }
 975
 976        return (void *)addr;
 977}
 978
 979static void vb_free(const void *addr, unsigned long size)
 980{
 981        unsigned long offset;
 982        unsigned long vb_idx;
 983        unsigned int order;
 984        struct vmap_block *vb;
 985
 986        BUG_ON(size & ~PAGE_MASK);
 987        BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
 988
 989        flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
 990
 991        order = get_order(size);
 992
 993        offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
 994
 995        vb_idx = addr_to_vb_idx((unsigned long)addr);
 996        rcu_read_lock();
 997        vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
 998        rcu_read_unlock();
 999        BUG_ON(!vb);
1000
1001        vunmap_page_range((unsigned long)addr, (unsigned long)addr + size);
1002
1003        spin_lock(&vb->lock);
1004        BUG_ON(bitmap_allocate_region(vb->dirty_map, offset >> PAGE_SHIFT, order));
1005
1006        vb->dirty += 1UL << order;
1007        if (vb->dirty == VMAP_BBMAP_BITS) {
1008                BUG_ON(vb->free);
1009                spin_unlock(&vb->lock);
1010                free_vmap_block(vb);
1011        } else
1012                spin_unlock(&vb->lock);
1013}
1014
1015/**
1016 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
1017 *
1018 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
1019 * to amortize TLB flushing overheads. What this means is that any page you
1020 * have now, may, in a former life, have been mapped into kernel virtual
1021 * address by the vmap layer and so there might be some CPUs with TLB entries
1022 * still referencing that page (additional to the regular 1:1 kernel mapping).
1023 *
1024 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
1025 * be sure that none of the pages we have control over will have any aliases
1026 * from the vmap layer.
1027 */
1028void vm_unmap_aliases(void)
1029{
1030        unsigned long start = ULONG_MAX, end = 0;
1031        int cpu;
1032        int flush = 0;
1033
1034        if (unlikely(!vmap_initialized))
1035                return;
1036
1037        for_each_possible_cpu(cpu) {
1038                struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1039                struct vmap_block *vb;
1040
1041                rcu_read_lock();
1042                list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1043                        int i;
1044
1045                        spin_lock(&vb->lock);
1046                        i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
1047                        while (i < VMAP_BBMAP_BITS) {
1048                                unsigned long s, e;
1049                                int j;
1050                                j = find_next_zero_bit(vb->dirty_map,
1051                                        VMAP_BBMAP_BITS, i);
1052
1053                                s = vb->va->va_start + (i << PAGE_SHIFT);
1054                                e = vb->va->va_start + (j << PAGE_SHIFT);
1055                                flush = 1;
1056
1057                                if (s < start)
1058                                        start = s;
1059                                if (e > end)
1060                                        end = e;
1061
1062                                i = j;
1063                                i = find_next_bit(vb->dirty_map,
1064                                                        VMAP_BBMAP_BITS, i);
1065                        }
1066                        spin_unlock(&vb->lock);
1067                }
1068                rcu_read_unlock();
1069        }
1070
1071        __purge_vmap_area_lazy(&start, &end, 1, flush);
1072}
1073EXPORT_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 */
1080void 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(addr & (PAGE_SIZE-1));
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}
1098EXPORT_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 * Returns: a pointer to the address that has been mapped, or %NULL on failure
1108 */
1109void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
1110{
1111        unsigned long size = count << PAGE_SHIFT;
1112        unsigned long addr;
1113        void *mem;
1114
1115        if (likely(count <= VMAP_MAX_ALLOC)) {
1116                mem = vb_alloc(size, GFP_KERNEL);
1117                if (IS_ERR(mem))
1118                        return NULL;
1119                addr = (unsigned long)mem;
1120        } else {
1121                struct vmap_area *va;
1122                va = alloc_vmap_area(size, PAGE_SIZE,
1123                                VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1124                if (IS_ERR(va))
1125                        return NULL;
1126
1127                addr = va->va_start;
1128                mem = (void *)addr;
1129        }
1130        if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
1131                vm_unmap_ram(mem, count);
1132                return NULL;
1133        }
1134        return mem;
1135}
1136EXPORT_SYMBOL(vm_map_ram);
1137
1138static struct vm_struct *vmlist __initdata;
1139/**
1140 * vm_area_add_early - add vmap area early during boot
1141 * @vm: vm_struct to add
1142 *
1143 * This function is used to add fixed kernel vm area to vmlist before
1144 * vmalloc_init() is called.  @vm->addr, @vm->size, and @vm->flags
1145 * should contain proper values and the other fields should be zero.
1146 *
1147 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1148 */
1149void __init vm_area_add_early(struct vm_struct *vm)
1150{
1151        struct vm_struct *tmp, **p;
1152
1153        BUG_ON(vmap_initialized);
1154        for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1155                if (tmp->addr >= vm->addr) {
1156                        BUG_ON(tmp->addr < vm->addr + vm->size);
1157                        break;
1158                } else
1159                        BUG_ON(tmp->addr + tmp->size > vm->addr);
1160        }
1161        vm->next = *p;
1162        *p = vm;
1163}
1164
1165/**
1166 * vm_area_register_early - register vmap area early during boot
1167 * @vm: vm_struct to register
1168 * @align: requested alignment
1169 *
1170 * This function is used to register kernel vm area before
1171 * vmalloc_init() is called.  @vm->size and @vm->flags should contain
1172 * proper values on entry and other fields should be zero.  On return,
1173 * vm->addr contains the allocated address.
1174 *
1175 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1176 */
1177void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1178{
1179        static size_t vm_init_off __initdata;
1180        unsigned long addr;
1181
1182        addr = ALIGN(VMALLOC_START + vm_init_off, align);
1183        vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1184
1185        vm->addr = (void *)addr;
1186
1187        vm_area_add_early(vm);
1188}
1189
1190void __init vmalloc_init(void)
1191{
1192        struct vmap_area *va;
1193        struct vm_struct *tmp;
1194        int i;
1195
1196        for_each_possible_cpu(i) {
1197                struct vmap_block_queue *vbq;
1198                struct vfree_deferred *p;
1199
1200                vbq = &per_cpu(vmap_block_queue, i);
1201                spin_lock_init(&vbq->lock);
1202                INIT_LIST_HEAD(&vbq->free);
1203                p = &per_cpu(vfree_deferred, i);
1204                init_llist_head(&p->list);
1205                INIT_WORK(&p->wq, free_work);
1206        }
1207
1208        /* Import existing vmlist entries. */
1209        for (tmp = vmlist; tmp; tmp = tmp->next) {
1210                va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
1211                va->flags = VM_VM_AREA;
1212                va->va_start = (unsigned long)tmp->addr;
1213                va->va_end = va->va_start + tmp->size;
1214                va->vm = tmp;
1215                __insert_vmap_area(va);
1216        }
1217
1218        vmap_area_pcpu_hole = VMALLOC_END;
1219
1220        vmap_initialized = true;
1221}
1222
1223/**
1224 * map_kernel_range_noflush - map kernel VM area with the specified pages
1225 * @addr: start of the VM area to map
1226 * @size: size of the VM area to map
1227 * @prot: page protection flags to use
1228 * @pages: pages to map
1229 *
1230 * Map PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1231 * specify should have been allocated using get_vm_area() and its
1232 * friends.
1233 *
1234 * NOTE:
1235 * This function does NOT do any cache flushing.  The caller is
1236 * responsible for calling flush_cache_vmap() on to-be-mapped areas
1237 * before calling this function.
1238 *
1239 * RETURNS:
1240 * The number of pages mapped on success, -errno on failure.
1241 */
1242int map_kernel_range_noflush(unsigned long addr, unsigned long size,
1243                             pgprot_t prot, struct page **pages)
1244{
1245        return vmap_page_range_noflush(addr, addr + size, prot, pages);
1246}
1247
1248/**
1249 * unmap_kernel_range_noflush - unmap kernel VM area
1250 * @addr: start of the VM area to unmap
1251 * @size: size of the VM area to unmap
1252 *
1253 * Unmap PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1254 * specify should have been allocated using get_vm_area() and its
1255 * friends.
1256 *
1257 * NOTE:
1258 * This function does NOT do any cache flushing.  The caller is
1259 * responsible for calling flush_cache_vunmap() on to-be-mapped areas
1260 * before calling this function and flush_tlb_kernel_range() after.
1261 */
1262void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
1263{
1264        vunmap_page_range(addr, addr + size);
1265}
1266EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush);
1267
1268/**
1269 * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
1270 * @addr: start of the VM area to unmap
1271 * @size: size of the VM area to unmap
1272 *
1273 * Similar to unmap_kernel_range_noflush() but flushes vcache before
1274 * the unmapping and tlb after.
1275 */
1276void unmap_kernel_range(unsigned long addr, unsigned long size)
1277{
1278        unsigned long end = addr + size;
1279
1280        flush_cache_vunmap(addr, end);
1281        vunmap_page_range(addr, end);
1282        flush_tlb_kernel_range(addr, end);
1283}
1284
1285int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
1286{
1287        unsigned long addr = (unsigned long)area->addr;
1288        unsigned long end = addr + area->size - PAGE_SIZE;
1289        int err;
1290
1291        err = vmap_page_range(addr, end, prot, *pages);
1292        if (err > 0) {
1293                *pages += err;
1294                err = 0;
1295        }
1296
1297        return err;
1298}
1299EXPORT_SYMBOL_GPL(map_vm_area);
1300
1301static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1302                              unsigned long flags, const void *caller)
1303{
1304        spin_lock(&vmap_area_lock);
1305        vm->flags = flags;
1306        vm->addr = (void *)va->va_start;
1307        vm->size = va->va_end - va->va_start;
1308        vm->caller = caller;
1309        va->vm = vm;
1310        va->flags |= VM_VM_AREA;
1311        spin_unlock(&vmap_area_lock);
1312}
1313
1314static void clear_vm_unlist(struct vm_struct *vm)
1315{
1316        /*
1317         * Before removing VM_UNLIST,
1318         * we should make sure that vm has proper values.
1319         * Pair with smp_rmb() in show_numa_info().
1320         */
1321        smp_wmb();
1322        vm->flags &= ~VM_UNLIST;
1323}
1324
1325static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1326                              unsigned long flags, const void *caller)
1327{
1328        setup_vmalloc_vm(vm, va, flags, caller);
1329        clear_vm_unlist(vm);
1330}
1331
1332static struct vm_struct *__get_vm_area_node(unsigned long size,
1333                unsigned long align, unsigned long flags, unsigned long start,
1334                unsigned long end, int node, gfp_t gfp_mask, const void *caller)
1335{
1336        struct vmap_area *va;
1337        struct vm_struct *area;
1338
1339        BUG_ON(in_interrupt());
1340        if (flags & VM_IOREMAP) {
1341                int bit = fls(size);
1342
1343                if (bit > IOREMAP_MAX_ORDER)
1344                        bit = IOREMAP_MAX_ORDER;
1345                else if (bit < PAGE_SHIFT)
1346                        bit = PAGE_SHIFT;
1347
1348                align = 1ul << bit;
1349        }
1350
1351        size = PAGE_ALIGN(size);
1352        if (unlikely(!size))
1353                return NULL;
1354
1355        area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
1356        if (unlikely(!area))
1357                return NULL;
1358
1359        /*
1360         * We always allocate a guard page.
1361         */
1362        size += PAGE_SIZE;
1363
1364        va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
1365        if (IS_ERR(va)) {
1366                kfree(area);
1367                return NULL;
1368        }
1369
1370        /*
1371         * When this function is called from __vmalloc_node_range,
1372         * we add VM_UNLIST flag to avoid accessing uninitialized
1373         * members of vm_struct such as pages and nr_pages fields.
1374         * They will be set later.
1375         */
1376        if (flags & VM_UNLIST)
1377                setup_vmalloc_vm(area, va, flags, caller);
1378        else
1379                insert_vmalloc_vm(area, va, flags, caller);
1380
1381        return area;
1382}
1383
1384struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
1385                                unsigned long start, unsigned long end)
1386{
1387        return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1388                                  GFP_KERNEL, __builtin_return_address(0));
1389}
1390EXPORT_SYMBOL_GPL(__get_vm_area);
1391
1392struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
1393                                       unsigned long start, unsigned long end,
1394                                       const void *caller)
1395{
1396        return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1397                                  GFP_KERNEL, caller);
1398}
1399
1400/**
1401 *      get_vm_area  -  reserve a contiguous kernel virtual area
1402 *      @size:          size of the area
1403 *      @flags:         %VM_IOREMAP for I/O mappings or VM_ALLOC
1404 *
1405 *      Search an area of @size in the kernel virtual mapping area,
1406 *      and reserved it for out purposes.  Returns the area descriptor
1407 *      on success or %NULL on failure.
1408 */
1409struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
1410{
1411        return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1412                                  NUMA_NO_NODE, GFP_KERNEL,
1413                                  __builtin_return_address(0));
1414}
1415
1416struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
1417                                const void *caller)
1418{
1419        return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1420                                  NUMA_NO_NODE, GFP_KERNEL, caller);
1421}
1422
1423/**
1424 *      find_vm_area  -  find a continuous kernel virtual area
1425 *      @addr:          base address
1426 *
1427 *      Search for the kernel VM area starting at @addr, and return it.
1428 *      It is up to the caller to do all required locking to keep the returned
1429 *      pointer valid.
1430 */
1431struct vm_struct *find_vm_area(const void *addr)
1432{
1433        struct vmap_area *va;
1434
1435        va = find_vmap_area((unsigned long)addr);
1436        if (va && va->flags & VM_VM_AREA)
1437                return va->vm;
1438
1439        return NULL;
1440}
1441
1442/**
1443 *      remove_vm_area  -  find and remove a continuous kernel virtual area
1444 *      @addr:          base address
1445 *
1446 *      Search for the kernel VM area starting at @addr, and remove it.
1447 *      This function returns the found VM area, but using it is NOT safe
1448 *      on SMP machines, except for its size or flags.
1449 */
1450struct vm_struct *remove_vm_area(const void *addr)
1451{
1452        struct vmap_area *va;
1453
1454        va = find_vmap_area((unsigned long)addr);
1455        if (va && va->flags & VM_VM_AREA) {
1456                struct vm_struct *vm = va->vm;
1457
1458                spin_lock(&vmap_area_lock);
1459                va->vm = NULL;
1460                va->flags &= ~VM_VM_AREA;
1461                spin_unlock(&vmap_area_lock);
1462
1463                vmap_debug_free_range(va->va_start, va->va_end);
1464                free_unmap_vmap_area(va);
1465                vm->size -= PAGE_SIZE;
1466
1467                return vm;
1468        }
1469        return NULL;
1470}
1471
1472static void __vunmap(const void *addr, int deallocate_pages)
1473{
1474        struct vm_struct *area;
1475
1476        if (!addr)
1477                return;
1478
1479        if ((PAGE_SIZE-1) & (unsigned long)addr) {
1480                WARN(1, KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
1481                return;
1482        }
1483
1484        area = remove_vm_area(addr);
1485        if (unlikely(!area)) {
1486                WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
1487                                addr);
1488                return;
1489        }
1490
1491        debug_check_no_locks_freed(addr, area->size);
1492        debug_check_no_obj_freed(addr, area->size);
1493
1494        if (deallocate_pages) {
1495                int i;
1496
1497                for (i = 0; i < area->nr_pages; i++) {
1498                        struct page *page = area->pages[i];
1499
1500                        BUG_ON(!page);
1501                        __free_page(page);
1502                }
1503
1504                if (area->flags & VM_VPAGES)
1505                        vfree(area->pages);
1506                else
1507                        kfree(area->pages);
1508        }
1509
1510        kfree(area);
1511        return;
1512}
1513 
1514/**
1515 *      vfree  -  release memory allocated by vmalloc()
1516 *      @addr:          memory base address
1517 *
1518 *      Free the virtually continuous memory area starting at @addr, as
1519 *      obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
1520 *      NULL, no operation is performed.
1521 *
1522 *      Must not be called in NMI context (strictly speaking, only if we don't
1523 *      have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
1524 *      conventions for vfree() arch-depenedent would be a really bad idea)
1525 *
1526 *      NOTE: assumes that the object at *addr has a size >= sizeof(llist_node)
1527 *      
1528 */
1529void vfree(const void *addr)
1530{
1531        BUG_ON(in_nmi());
1532
1533        kmemleak_free(addr);
1534
1535        if (!addr)
1536                return;
1537        if (unlikely(in_interrupt())) {
1538                struct vfree_deferred *p = &__get_cpu_var(vfree_deferred);
1539                llist_add((struct llist_node *)addr, &p->list);
1540                schedule_work(&p->wq);
1541        } else
1542                __vunmap(addr, 1);
1543}
1544EXPORT_SYMBOL(vfree);
1545
1546/**
1547 *      vunmap  -  release virtual mapping obtained by vmap()
1548 *      @addr:          memory base address
1549 *
1550 *      Free the virtually contiguous memory area starting at @addr,
1551 *      which was created from the page array passed to vmap().
1552 *
1553 *      Must not be called in interrupt context.
1554 */
1555void vunmap(const void *addr)
1556{
1557        BUG_ON(in_interrupt());
1558        might_sleep();
1559        if (addr)
1560                __vunmap(addr, 0);
1561}
1562EXPORT_SYMBOL(vunmap);
1563
1564/**
1565 *      vmap  -  map an array of pages into virtually contiguous space
1566 *      @pages:         array of page pointers
1567 *      @count:         number of pages to map
1568 *      @flags:         vm_area->flags
1569 *      @prot:          page protection for the mapping
1570 *
1571 *      Maps @count pages from @pages into contiguous kernel virtual
1572 *      space.
1573 */
1574void *vmap(struct page **pages, unsigned int count,
1575                unsigned long flags, pgprot_t prot)
1576{
1577        struct vm_struct *area;
1578
1579        might_sleep();
1580
1581        if (count > totalram_pages)
1582                return NULL;
1583
1584        area = get_vm_area_caller((count << PAGE_SHIFT), flags,
1585                                        __builtin_return_address(0));
1586        if (!area)
1587                return NULL;
1588
1589        if (map_vm_area(area, prot, &pages)) {
1590                vunmap(area->addr);
1591                return NULL;
1592        }
1593
1594        return area->addr;
1595}
1596EXPORT_SYMBOL(vmap);
1597
1598static void *__vmalloc_node(unsigned long size, unsigned long align,
1599                            gfp_t gfp_mask, pgprot_t prot,
1600                            int node, const void *caller);
1601static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
1602                                 pgprot_t prot, int node, const void *caller)
1603{
1604        const int order = 0;
1605        struct page **pages;
1606        unsigned int nr_pages, array_size, i;
1607        gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
1608
1609        nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
1610        array_size = (nr_pages * sizeof(struct page *));
1611
1612        area->nr_pages = nr_pages;
1613        /* Please note that the recursion is strictly bounded. */
1614        if (array_size > PAGE_SIZE) {
1615                pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM,
1616                                PAGE_KERNEL, node, caller);
1617                area->flags |= VM_VPAGES;
1618        } else {
1619                pages = kmalloc_node(array_size, nested_gfp, node);
1620        }
1621        area->pages = pages;
1622        area->caller = caller;
1623        if (!area->pages) {
1624                remove_vm_area(area->addr);
1625                kfree(area);
1626                return NULL;
1627        }
1628
1629        for (i = 0; i < area->nr_pages; i++) {
1630                struct page *page;
1631                gfp_t tmp_mask = gfp_mask | __GFP_NOWARN;
1632
1633                if (node < 0)
1634                        page = alloc_page(tmp_mask);
1635                else
1636                        page = alloc_pages_node(node, tmp_mask, order);
1637
1638                if (unlikely(!page)) {
1639                        /* Successfully allocated i pages, free them in __vunmap() */
1640                        area->nr_pages = i;
1641                        goto fail;
1642                }
1643                area->pages[i] = page;
1644        }
1645
1646        if (map_vm_area(area, prot, &pages))
1647                goto fail;
1648        return area->addr;
1649
1650fail:
1651        warn_alloc_failed(gfp_mask, order,
1652                          "vmalloc: allocation failure, allocated %ld of %ld bytes\n",
1653                          (area->nr_pages*PAGE_SIZE), area->size);
1654        vfree(area->addr);
1655        return NULL;
1656}
1657
1658/**
1659 *      __vmalloc_node_range  -  allocate virtually contiguous memory
1660 *      @size:          allocation size
1661 *      @align:         desired alignment
1662 *      @start:         vm area range start
1663 *      @end:           vm area range end
1664 *      @gfp_mask:      flags for the page level allocator
1665 *      @prot:          protection mask for the allocated pages
1666 *      @node:          node to use for allocation or NUMA_NO_NODE
1667 *      @caller:        caller's return address
1668 *
1669 *      Allocate enough pages to cover @size from the page level
1670 *      allocator with @gfp_mask flags.  Map them into contiguous
1671 *      kernel virtual space, using a pagetable protection of @prot.
1672 */
1673void *__vmalloc_node_range(unsigned long size, unsigned long align,
1674                        unsigned long start, unsigned long end, gfp_t gfp_mask,
1675                        pgprot_t prot, int node, const void *caller)
1676{
1677        struct vm_struct *area;
1678        void *addr;
1679        unsigned long real_size = size;
1680
1681        size = PAGE_ALIGN(size);
1682        if (!size || (size >> PAGE_SHIFT) > totalram_pages)
1683                goto fail;
1684
1685        area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST,
1686                                  start, end, node, gfp_mask, caller);
1687        if (!area)
1688                goto fail;
1689
1690        addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
1691        if (!addr)
1692                return NULL;
1693
1694        /*
1695         * In this function, newly allocated vm_struct has VM_UNLIST flag.
1696         * It means that vm_struct is not fully initialized.
1697         * Now, it is fully initialized, so remove this flag here.
1698         */
1699        clear_vm_unlist(area);
1700
1701        /*
1702         * A ref_count = 3 is needed because the vm_struct and vmap_area
1703         * structures allocated in the __get_vm_area_node() function contain
1704         * references to the virtual address of the vmalloc'ed block.
1705         */
1706        kmemleak_alloc(addr, real_size, 3, gfp_mask);
1707
1708        return addr;
1709
1710fail:
1711        warn_alloc_failed(gfp_mask, 0,
1712                          "vmalloc: allocation failure: %lu bytes\n",
1713                          real_size);
1714        return NULL;
1715}
1716
1717/**
1718 *      __vmalloc_node  -  allocate virtually contiguous memory
1719 *      @size:          allocation size
1720 *      @align:         desired alignment
1721 *      @gfp_mask:      flags for the page level allocator
1722 *      @prot:          protection mask for the allocated pages
1723 *      @node:          node to use for allocation or NUMA_NO_NODE
1724 *      @caller:        caller's return address
1725 *
1726 *      Allocate enough pages to cover @size from the page level
1727 *      allocator with @gfp_mask flags.  Map them into contiguous
1728 *      kernel virtual space, using a pagetable protection of @prot.
1729 */
1730static void *__vmalloc_node(unsigned long size, unsigned long align,
1731                            gfp_t gfp_mask, pgprot_t prot,
1732                            int node, const void *caller)
1733{
1734        return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
1735                                gfp_mask, prot, node, caller);
1736}
1737
1738void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1739{
1740        return __vmalloc_node(size, 1, gfp_mask, prot, NUMA_NO_NODE,
1741                                __builtin_return_address(0));
1742}
1743EXPORT_SYMBOL(__vmalloc);
1744
1745static inline void *__vmalloc_node_flags(unsigned long size,
1746                                        int node, gfp_t flags)
1747{
1748        return __vmalloc_node(size, 1, flags, PAGE_KERNEL,
1749                                        node, __builtin_return_address(0));
1750}
1751
1752/**
1753 *      vmalloc  -  allocate virtually contiguous memory
1754 *      @size:          allocation size
1755 *      Allocate enough pages to cover @size from the page level
1756 *      allocator and map them into contiguous kernel virtual space.
1757 *
1758 *      For tight control over page level allocator and protection flags
1759 *      use __vmalloc() instead.
1760 */
1761void *vmalloc(unsigned long size)
1762{
1763        return __vmalloc_node_flags(size, NUMA_NO_NODE,
1764                                    GFP_KERNEL | __GFP_HIGHMEM);
1765}
1766EXPORT_SYMBOL(vmalloc);
1767
1768/**
1769 *      vzalloc - allocate virtually contiguous memory with zero fill
1770 *      @size:  allocation size
1771 *      Allocate enough pages to cover @size from the page level
1772 *      allocator and map them into contiguous kernel virtual space.
1773 *      The memory allocated is set to zero.
1774 *
1775 *      For tight control over page level allocator and protection flags
1776 *      use __vmalloc() instead.
1777 */
1778void *vzalloc(unsigned long size)
1779{
1780        return __vmalloc_node_flags(size, NUMA_NO_NODE,
1781                                GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1782}
1783EXPORT_SYMBOL(vzalloc);
1784
1785/**
1786 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
1787 * @size: allocation size
1788 *
1789 * The resulting memory area is zeroed so it can be mapped to userspace
1790 * without leaking data.
1791 */
1792void *vmalloc_user(unsigned long size)
1793{
1794        struct vm_struct *area;
1795        void *ret;
1796
1797        ret = __vmalloc_node(size, SHMLBA,
1798                             GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
1799                             PAGE_KERNEL, NUMA_NO_NODE,
1800                             __builtin_return_address(0));
1801        if (ret) {
1802                area = find_vm_area(ret);
1803                area->flags |= VM_USERMAP;
1804        }
1805        return ret;
1806}
1807EXPORT_SYMBOL(vmalloc_user);
1808
1809/**
1810 *      vmalloc_node  -  allocate memory on a specific node
1811 *      @size:          allocation size
1812 *      @node:          numa node
1813 *
1814 *      Allocate enough pages to cover @size from the page level
1815 *      allocator and map them into contiguous kernel virtual space.
1816 *
1817 *      For tight control over page level allocator and protection flags
1818 *      use __vmalloc() instead.
1819 */
1820void *vmalloc_node(unsigned long size, int node)
1821{
1822        return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
1823                                        node, __builtin_return_address(0));
1824}
1825EXPORT_SYMBOL(vmalloc_node);
1826
1827/**
1828 * vzalloc_node - allocate memory on a specific node with zero fill
1829 * @size:       allocation size
1830 * @node:       numa node
1831 *
1832 * Allocate enough pages to cover @size from the page level
1833 * allocator and map them into contiguous kernel virtual space.
1834 * The memory allocated is set to zero.
1835 *
1836 * For tight control over page level allocator and protection flags
1837 * use __vmalloc_node() instead.
1838 */
1839void *vzalloc_node(unsigned long size, int node)
1840{
1841        return __vmalloc_node_flags(size, node,
1842                         GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1843}
1844EXPORT_SYMBOL(vzalloc_node);
1845
1846#ifndef PAGE_KERNEL_EXEC
1847# define PAGE_KERNEL_EXEC PAGE_KERNEL
1848#endif
1849
1850/**
1851 *      vmalloc_exec  -  allocate virtually contiguous, executable memory
1852 *      @size:          allocation size
1853 *
1854 *      Kernel-internal function to allocate enough pages to cover @size
1855 *      the page level allocator and map them into contiguous and
1856 *      executable kernel virtual space.
1857 *
1858 *      For tight control over page level allocator and protection flags
1859 *      use __vmalloc() instead.
1860 */
1861
1862void *vmalloc_exec(unsigned long size)
1863{
1864        return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
1865                              NUMA_NO_NODE, __builtin_return_address(0));
1866}
1867
1868#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
1869#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
1870#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
1871#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
1872#else
1873#define GFP_VMALLOC32 GFP_KERNEL
1874#endif
1875
1876/**
1877 *      vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
1878 *      @size:          allocation size
1879 *
1880 *      Allocate enough 32bit PA addressable pages to cover @size from the
1881 *      page level allocator and map them into contiguous kernel virtual space.
1882 */
1883void *vmalloc_32(unsigned long size)
1884{
1885        return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
1886                              NUMA_NO_NODE, __builtin_return_address(0));
1887}
1888EXPORT_SYMBOL(vmalloc_32);
1889
1890/**
1891 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
1892 *      @size:          allocation size
1893 *
1894 * The resulting memory area is 32bit addressable and zeroed so it can be
1895 * mapped to userspace without leaking data.
1896 */
1897void *vmalloc_32_user(unsigned long size)
1898{
1899        struct vm_struct *area;
1900        void *ret;
1901
1902        ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
1903                             NUMA_NO_NODE, __builtin_return_address(0));
1904        if (ret) {
1905                area = find_vm_area(ret);
1906                area->flags |= VM_USERMAP;
1907        }
1908        return ret;
1909}
1910EXPORT_SYMBOL(vmalloc_32_user);
1911
1912/*
1913 * small helper routine , copy contents to buf from addr.
1914 * If the page is not present, fill zero.
1915 */
1916
1917static int aligned_vread(char *buf, char *addr, unsigned long count)
1918{
1919        struct page *p;
1920        int copied = 0;
1921
1922        while (count) {
1923                unsigned long offset, length;
1924
1925                offset = (unsigned long)addr & ~PAGE_MASK;
1926                length = PAGE_SIZE - offset;
1927                if (length > count)
1928                        length = count;
1929                p = vmalloc_to_page(addr);
1930                /*
1931                 * To do safe access to this _mapped_ area, we need
1932                 * lock. But adding lock here means that we need to add
1933                 * overhead of vmalloc()/vfree() calles for this _debug_
1934                 * interface, rarely used. Instead of that, we'll use
1935                 * kmap() and get small overhead in this access function.
1936                 */
1937                if (p) {
1938                        /*
1939                         * we can expect USER0 is not used (see vread/vwrite's
1940                         * function description)
1941                         */
1942                        void *map = kmap_atomic(p);
1943                        memcpy(buf, map + offset, length);
1944                        kunmap_atomic(map);
1945                } else
1946                        memset(buf, 0, length);
1947
1948                addr += length;
1949                buf += length;
1950                copied += length;
1951                count -= length;
1952        }
1953        return copied;
1954}
1955
1956static int aligned_vwrite(char *buf, char *addr, unsigned long count)
1957{
1958        struct page *p;
1959        int copied = 0;
1960
1961        while (count) {
1962                unsigned long offset, length;
1963
1964                offset = (unsigned long)addr & ~PAGE_MASK;
1965                length = PAGE_SIZE - offset;
1966                if (length > count)
1967                        length = count;
1968                p = vmalloc_to_page(addr);
1969                /*
1970                 * To do safe access to this _mapped_ area, we need
1971                 * lock. But adding lock here means that we need to add
1972                 * overhead of vmalloc()/vfree() calles for this _debug_
1973                 * interface, rarely used. Instead of that, we'll use
1974                 * kmap() and get small overhead in this access function.
1975                 */
1976                if (p) {
1977                        /*
1978                         * we can expect USER0 is not used (see vread/vwrite's
1979                         * function description)
1980                         */
1981                        void *map = kmap_atomic(p);
1982                        memcpy(map + offset, buf, length);
1983                        kunmap_atomic(map);
1984                }
1985                addr += length;
1986                buf += length;
1987                copied += length;
1988                count -= length;
1989        }
1990        return copied;
1991}
1992
1993/**
1994 *      vread() -  read vmalloc area in a safe way.
1995 *      @buf:           buffer for reading data
1996 *      @addr:          vm address.
1997 *      @count:         number of bytes to be read.
1998 *
1999 *      Returns # of bytes which addr and buf should be increased.
2000 *      (same number to @count). Returns 0 if [addr...addr+count) doesn't
2001 *      includes any intersect with alive vmalloc area.
2002 *
2003 *      This function checks that addr is a valid vmalloc'ed area, and
2004 *      copy data from that area to a given buffer. If the given memory range
2005 *      of [addr...addr+count) includes some valid address, data is copied to
2006 *      proper area of @buf. If there are memory holes, they'll be zero-filled.
2007 *      IOREMAP area is treated as memory hole and no copy is done.
2008 *
2009 *      If [addr...addr+count) doesn't includes any intersects with alive
2010 *      vm_struct area, returns 0. @buf should be kernel's buffer.
2011 *
2012 *      Note: In usual ops, vread() is never necessary because the caller
2013 *      should know vmalloc() area is valid and can use memcpy().
2014 *      This is for routines which have to access vmalloc area without
2015 *      any informaion, as /dev/kmem.
2016 *
2017 */
2018
2019long vread(char *buf, char *addr, unsigned long count)
2020{
2021        struct vmap_area *va;
2022        struct vm_struct *vm;
2023        char *vaddr, *buf_start = buf;
2024        unsigned long buflen = count;
2025        unsigned long n;
2026
2027        /* Don't allow overflow */
2028        if ((unsigned long) addr + count < count)
2029                count = -(unsigned long) addr;
2030
2031        spin_lock(&vmap_area_lock);
2032        list_for_each_entry(va, &vmap_area_list, list) {
2033                if (!count)
2034                        break;
2035
2036                if (!(va->flags & VM_VM_AREA))
2037                        continue;
2038
2039                vm = va->vm;
2040                vaddr = (char *) vm->addr;
2041                if (addr >= vaddr + vm->size - PAGE_SIZE)
2042                        continue;
2043                while (addr < vaddr) {
2044                        if (count == 0)
2045                                goto finished;
2046                        *buf = '\0';
2047                        buf++;
2048                        addr++;
2049                        count--;
2050                }
2051                n = vaddr + vm->size - PAGE_SIZE - addr;
2052                if (n > count)
2053                        n = count;
2054                if (!(vm->flags & VM_IOREMAP))
2055                        aligned_vread(buf, addr, n);
2056                else /* IOREMAP area is treated as memory hole */
2057                        memset(buf, 0, n);
2058                buf += n;
2059                addr += n;
2060                count -= n;
2061        }
2062finished:
2063        spin_unlock(&vmap_area_lock);
2064
2065        if (buf == buf_start)
2066                return 0;
2067        /* zero-fill memory holes */
2068        if (buf != buf_start + buflen)
2069                memset(buf, 0, buflen - (buf - buf_start));
2070
2071        return buflen;
2072}
2073
2074/**
2075 *      vwrite() -  write vmalloc area in a safe way.
2076 *      @buf:           buffer for source data
2077 *      @addr:          vm address.
2078 *      @count:         number of bytes to be read.
2079 *
2080 *      Returns # of bytes which addr and buf should be incresed.
2081 *      (same number to @count).
2082 *      If [addr...addr+count) doesn't includes any intersect with valid
2083 *      vmalloc area, returns 0.
2084 *
2085 *      This function checks that addr is a valid vmalloc'ed area, and
2086 *      copy data from a buffer to the given addr. If specified range of
2087 *      [addr...addr+count) includes some valid address, data is copied from
2088 *      proper area of @buf. If there are memory holes, no copy to hole.
2089 *      IOREMAP area is treated as memory hole and no copy is done.
2090 *
2091 *      If [addr...addr+count) doesn't includes any intersects with alive
2092 *      vm_struct area, returns 0. @buf should be kernel's buffer.
2093 *
2094 *      Note: In usual ops, vwrite() is never necessary because the caller
2095 *      should know vmalloc() area is valid and can use memcpy().
2096 *      This is for routines which have to access vmalloc area without
2097 *      any informaion, as /dev/kmem.
2098 */
2099
2100long vwrite(char *buf, char *addr, unsigned long count)
2101{
2102        struct vmap_area *va;
2103        struct vm_struct *vm;
2104        char *vaddr;
2105        unsigned long n, buflen;
2106        int copied = 0;
2107
2108        /* Don't allow overflow */
2109        if ((unsigned long) addr + count < count)
2110                count = -(unsigned long) addr;
2111        buflen = count;
2112
2113        spin_lock(&vmap_area_lock);
2114        list_for_each_entry(va, &vmap_area_list, list) {
2115                if (!count)
2116                        break;
2117
2118                if (!(va->flags & VM_VM_AREA))
2119                        continue;
2120
2121                vm = va->vm;
2122                vaddr = (char *) vm->addr;
2123                if (addr >= vaddr + vm->size - PAGE_SIZE)
2124                        continue;
2125                while (addr < vaddr) {
2126                        if (count == 0)
2127                                goto finished;
2128                        buf++;
2129                        addr++;
2130                        count--;
2131                }
2132                n = vaddr + vm->size - PAGE_SIZE - addr;
2133                if (n > count)
2134                        n = count;
2135                if (!(vm->flags & VM_IOREMAP)) {
2136                        aligned_vwrite(buf, addr, n);
2137                        copied++;
2138                }
2139                buf += n;
2140                addr += n;
2141                count -= n;
2142        }
2143finished:
2144        spin_unlock(&vmap_area_lock);
2145        if (!copied)
2146                return 0;
2147        return buflen;
2148}
2149
2150/**
2151 *      remap_vmalloc_range  -  map vmalloc pages to userspace
2152 *      @vma:           vma to cover (map full range of vma)
2153 *      @addr:          vmalloc memory
2154 *      @pgoff:         number of pages into addr before first page to map
2155 *
2156 *      Returns:        0 for success, -Exxx on failure
2157 *
2158 *      This function checks that addr is a valid vmalloc'ed area, and
2159 *      that it is big enough to cover the vma. Will return failure if
2160 *      that criteria isn't met.
2161 *
2162 *      Similar to remap_pfn_range() (see mm/memory.c)
2163 */
2164int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
2165                                                unsigned long pgoff)
2166{
2167        struct vm_struct *area;
2168        unsigned long uaddr = vma->vm_start;
2169        unsigned long usize = vma->vm_end - vma->vm_start;
2170
2171        if ((PAGE_SIZE-1) & (unsigned long)addr)
2172                return -EINVAL;
2173
2174        area = find_vm_area(addr);
2175        if (!area)
2176                return -EINVAL;
2177
2178        if (!(area->flags & VM_USERMAP))
2179                return -EINVAL;
2180
2181        if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
2182                return -EINVAL;
2183
2184        addr += pgoff << PAGE_SHIFT;
2185        do {
2186                struct page *page = vmalloc_to_page(addr);
2187                int ret;
2188
2189                ret = vm_insert_page(vma, uaddr, page);
2190                if (ret)
2191                        return ret;
2192
2193                uaddr += PAGE_SIZE;
2194                addr += PAGE_SIZE;
2195                usize -= PAGE_SIZE;
2196        } while (usize > 0);
2197
2198        vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
2199
2200        return 0;
2201}
2202EXPORT_SYMBOL(remap_vmalloc_range);
2203
2204/*
2205 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
2206 * have one.
2207 */
2208void  __attribute__((weak)) vmalloc_sync_all(void)
2209{
2210}
2211
2212
2213static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
2214{
2215        pte_t ***p = data;
2216
2217        if (p) {
2218                *(*p) = pte;
2219                (*p)++;
2220        }
2221        return 0;
2222}
2223
2224/**
2225 *      alloc_vm_area - allocate a range of kernel address space
2226 *      @size:          size of the area
2227 *      @ptes:          returns the PTEs for the address space
2228 *
2229 *      Returns:        NULL on failure, vm_struct on success
2230 *
2231 *      This function reserves a range of kernel address space, and
2232 *      allocates pagetables to map that range.  No actual mappings
2233 *      are created.
2234 *
2235 *      If @ptes is non-NULL, pointers to the PTEs (in init_mm)
2236 *      allocated for the VM area are returned.
2237 */
2238struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
2239{
2240        struct vm_struct *area;
2241
2242        area = get_vm_area_caller(size, VM_IOREMAP,
2243                                __builtin_return_address(0));
2244        if (area == NULL)
2245                return NULL;
2246
2247        /*
2248         * This ensures that page tables are constructed for this region
2249         * of kernel virtual address space and mapped into init_mm.
2250         */
2251        if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2252                                size, f, ptes ? &ptes : NULL)) {
2253                free_vm_area(area);
2254                return NULL;
2255        }
2256
2257        return area;
2258}
2259EXPORT_SYMBOL_GPL(alloc_vm_area);
2260
2261void free_vm_area(struct vm_struct *area)
2262{
2263        struct vm_struct *ret;
2264        ret = remove_vm_area(area->addr);
2265        BUG_ON(ret != area);
2266        kfree(area);
2267}
2268EXPORT_SYMBOL_GPL(free_vm_area);
2269
2270#ifdef CONFIG_SMP
2271static struct vmap_area *node_to_va(struct rb_node *n)
2272{
2273        return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
2274}
2275
2276/**
2277 * pvm_find_next_prev - find the next and prev vmap_area surrounding @end
2278 * @end: target address
2279 * @pnext: out arg for the next vmap_area
2280 * @pprev: out arg for the previous vmap_area
2281 *
2282 * Returns: %true if either or both of next and prev are found,
2283 *          %false if no vmap_area exists
2284 *
2285 * Find vmap_areas end addresses of which enclose @end.  ie. if not
2286 * NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
2287 */
2288static bool pvm_find_next_prev(unsigned long end,
2289                               struct vmap_area **pnext,
2290                               struct vmap_area **pprev)
2291{
2292        struct rb_node *n = vmap_area_root.rb_node;
2293        struct vmap_area *va = NULL;
2294
2295        while (n) {
2296                va = rb_entry(n, struct vmap_area, rb_node);
2297                if (end < va->va_end)
2298                        n = n->rb_left;
2299                else if (end > va->va_end)
2300                        n = n->rb_right;
2301                else
2302                        break;
2303        }
2304
2305        if (!va)
2306                return false;
2307
2308        if (va->va_end > end) {
2309                *pnext = va;
2310                *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2311        } else {
2312                *pprev = va;
2313                *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
2314        }
2315        return true;
2316}
2317
2318/**
2319 * pvm_determine_end - find the highest aligned address between two vmap_areas
2320 * @pnext: in/out arg for the next vmap_area
2321 * @pprev: in/out arg for the previous vmap_area
2322 * @align: alignment
2323 *
2324 * Returns: determined end address
2325 *
2326 * Find the highest aligned address between *@pnext and *@pprev below
2327 * VMALLOC_END.  *@pnext and *@pprev are adjusted so that the aligned
2328 * down address is between the end addresses of the two vmap_areas.
2329 *
2330 * Please note that the address returned by this function may fall
2331 * inside *@pnext vmap_area.  The caller is responsible for checking
2332 * that.
2333 */
2334static unsigned long pvm_determine_end(struct vmap_area **pnext,
2335                                       struct vmap_area **pprev,
2336                                       unsigned long align)
2337{
2338        const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2339        unsigned long addr;
2340
2341        if (*pnext)
2342                addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
2343        else
2344                addr = vmalloc_end;
2345
2346        while (*pprev && (*pprev)->va_end > addr) {
2347                *pnext = *pprev;
2348                *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2349        }
2350
2351        return addr;
2352}
2353
2354/**
2355 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
2356 * @offsets: array containing offset of each area
2357 * @sizes: array containing size of each area
2358 * @nr_vms: the number of areas to allocate
2359 * @align: alignment, all entries in @offsets and @sizes must be aligned to this
2360 *
2361 * Returns: kmalloc'd vm_struct pointer array pointing to allocated
2362 *          vm_structs on success, %NULL on failure
2363 *
2364 * Percpu allocator wants to use congruent vm areas so that it can
2365 * maintain the offsets among percpu areas.  This function allocates
2366 * congruent vmalloc areas for it with GFP_KERNEL.  These areas tend to
2367 * be scattered pretty far, distance between two areas easily going up
2368 * to gigabytes.  To avoid interacting with regular vmallocs, these
2369 * areas are allocated from top.
2370 *
2371 * Despite its complicated look, this allocator is rather simple.  It
2372 * does everything top-down and scans areas from the end looking for
2373 * matching slot.  While scanning, if any of the areas overlaps with
2374 * existing vmap_area, the base address is pulled down to fit the
2375 * area.  Scanning is repeated till all the areas fit and then all
2376 * necessary data structres are inserted and the result is returned.
2377 */
2378struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
2379                                     const size_t *sizes, int nr_vms,
2380                                     size_t align)
2381{
2382        const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
2383        const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2384        struct vmap_area **vas, *prev, *next;
2385        struct vm_struct **vms;
2386        int area, area2, last_area, term_area;
2387        unsigned long base, start, end, last_end;
2388        bool purged = false;
2389
2390        /* verify parameters and allocate data structures */
2391        BUG_ON(align & ~PAGE_MASK || !is_power_of_2(align));
2392        for (last_area = 0, area = 0; area < nr_vms; area++) {
2393                start = offsets[area];
2394                end = start + sizes[area];
2395
2396                /* is everything aligned properly? */
2397                BUG_ON(!IS_ALIGNED(offsets[area], align));
2398                BUG_ON(!IS_ALIGNED(sizes[area], align));
2399
2400                /* detect the area with the highest address */
2401                if (start > offsets[last_area])
2402                        last_area = area;
2403
2404                for (area2 = 0; area2 < nr_vms; area2++) {
2405                        unsigned long start2 = offsets[area2];
2406                        unsigned long end2 = start2 + sizes[area2];
2407
2408                        if (area2 == area)
2409                                continue;
2410
2411                        BUG_ON(start2 >= start && start2 < end);
2412                        BUG_ON(end2 <= end && end2 > start);
2413                }
2414        }
2415        last_end = offsets[last_area] + sizes[last_area];
2416
2417        if (vmalloc_end - vmalloc_start < last_end) {
2418                WARN_ON(true);
2419                return NULL;
2420        }
2421
2422        vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
2423        vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
2424        if (!vas || !vms)
2425                goto err_free2;
2426
2427        for (area = 0; area < nr_vms; area++) {
2428                vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL);
2429                vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
2430                if (!vas[area] || !vms[area])
2431                        goto err_free;
2432        }
2433retry:
2434        spin_lock(&vmap_area_lock);
2435
2436        /* start scanning - we scan from the top, begin with the last area */
2437        area = term_area = last_area;
2438        start = offsets[area];
2439        end = start + sizes[area];
2440
2441        if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
2442                base = vmalloc_end - last_end;
2443                goto found;
2444        }
2445        base = pvm_determine_end(&next, &prev, align) - end;
2446
2447        while (true) {
2448                BUG_ON(next && next->va_end <= base + end);
2449                BUG_ON(prev && prev->va_end > base + end);
2450
2451                /*
2452                 * base might have underflowed, add last_end before
2453                 * comparing.
2454                 */
2455                if (base + last_end < vmalloc_start + last_end) {
2456                        spin_unlock(&vmap_area_lock);
2457                        if (!purged) {
2458                                purge_vmap_area_lazy();
2459                                purged = true;
2460                                goto retry;
2461                        }
2462                        goto err_free;
2463                }
2464
2465                /*
2466                 * If next overlaps, move base downwards so that it's
2467                 * right below next and then recheck.
2468                 */
2469                if (next && next->va_start < base + end) {
2470                        base = pvm_determine_end(&next, &prev, align) - end;
2471                        term_area = area;
2472                        continue;
2473                }
2474
2475                /*
2476                 * If prev overlaps, shift down next and prev and move
2477                 * base so that it's right below new next and then
2478                 * recheck.
2479                 */
2480                if (prev && prev->va_end > base + start)  {
2481                        next = prev;
2482                        prev = node_to_va(rb_prev(&next->rb_node));
2483                        base = pvm_determine_end(&next, &prev, align) - end;
2484                        term_area = area;
2485                        continue;
2486                }
2487
2488                /*
2489                 * This area fits, move on to the previous one.  If
2490                 * the previous one is the terminal one, we're done.
2491                 */
2492                area = (area + nr_vms - 1) % nr_vms;
2493                if (area == term_area)
2494                        break;
2495                start = offsets[area];
2496                end = start + sizes[area];
2497                pvm_find_next_prev(base + end, &next, &prev);
2498        }
2499found:
2500        /* we've found a fitting base, insert all va's */
2501        for (area = 0; area < nr_vms; area++) {
2502                struct vmap_area *va = vas[area];
2503
2504                va->va_start = base + offsets[area];
2505                va->va_end = va->va_start + sizes[area];
2506                __insert_vmap_area(va);
2507        }
2508
2509        vmap_area_pcpu_hole = base + offsets[last_area];
2510
2511        spin_unlock(&vmap_area_lock);
2512
2513        /* insert all vm's */
2514        for (area = 0; area < nr_vms; area++)
2515                insert_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
2516                                  pcpu_get_vm_areas);
2517
2518        kfree(vas);
2519        return vms;
2520
2521err_free:
2522        for (area = 0; area < nr_vms; area++) {
2523                kfree(vas[area]);
2524                kfree(vms[area]);
2525        }
2526err_free2:
2527        kfree(vas);
2528        kfree(vms);
2529        return NULL;
2530}
2531
2532/**
2533 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
2534 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
2535 * @nr_vms: the number of allocated areas
2536 *
2537 * Free vm_structs and the array allocated by pcpu_get_vm_areas().
2538 */
2539void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
2540{
2541        int i;
2542
2543        for (i = 0; i < nr_vms; i++)
2544                free_vm_area(vms[i]);
2545        kfree(vms);
2546}
2547#endif  /* CONFIG_SMP */
2548
2549#ifdef CONFIG_PROC_FS
2550static void *s_start(struct seq_file *m, loff_t *pos)
2551        __acquires(&vmap_area_lock)
2552{
2553        loff_t n = *pos;
2554        struct vmap_area *va;
2555
2556        spin_lock(&vmap_area_lock);
2557        va = list_entry((&vmap_area_list)->next, typeof(*va), list);
2558        while (n > 0 && &va->list != &vmap_area_list) {
2559                n--;
2560                va = list_entry(va->list.next, typeof(*va), list);
2561        }
2562        if (!n && &va->list != &vmap_area_list)
2563                return va;
2564
2565        return NULL;
2566
2567}
2568
2569static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2570{
2571        struct vmap_area *va = p, *next;
2572
2573        ++*pos;
2574        next = list_entry(va->list.next, typeof(*va), list);
2575        if (&next->list != &vmap_area_list)
2576                return next;
2577
2578        return NULL;
2579}
2580
2581static void s_stop(struct seq_file *m, void *p)
2582        __releases(&vmap_area_lock)
2583{
2584        spin_unlock(&vmap_area_lock);
2585}
2586
2587static void show_numa_info(struct seq_file *m, struct vm_struct *v)
2588{
2589        if (IS_ENABLED(CONFIG_NUMA)) {
2590                unsigned int nr, *counters = m->private;
2591
2592                if (!counters)
2593                        return;
2594
2595                /* Pair with smp_wmb() in clear_vm_unlist() */
2596                smp_rmb();
2597                if (v->flags & VM_UNLIST)
2598                        return;
2599
2600                memset(counters, 0, nr_node_ids * sizeof(unsigned int));
2601
2602                for (nr = 0; nr < v->nr_pages; nr++)
2603                        counters[page_to_nid(v->pages[nr])]++;
2604
2605                for_each_node_state(nr, N_HIGH_MEMORY)
2606                        if (counters[nr])
2607                                seq_printf(m, " N%u=%u", nr, counters[nr]);
2608        }
2609}
2610
2611static int s_show(struct seq_file *m, void *p)
2612{
2613        struct vmap_area *va = p;
2614        struct vm_struct *v;
2615
2616        if (va->flags & (VM_LAZY_FREE | VM_LAZY_FREEING))
2617                return 0;
2618
2619        if (!(va->flags & VM_VM_AREA)) {
2620                seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
2621                        (void *)va->va_start, (void *)va->va_end,
2622                                        va->va_end - va->va_start);
2623                return 0;
2624        }
2625
2626        v = va->vm;
2627
2628        seq_printf(m, "0x%pK-0x%pK %7ld",
2629                v->addr, v->addr + v->size, v->size);
2630
2631        if (v->caller)
2632                seq_printf(m, " %pS", v->caller);
2633
2634        if (v->nr_pages)
2635                seq_printf(m, " pages=%d", v->nr_pages);
2636
2637        if (v->phys_addr)
2638                seq_printf(m, " phys=%llx", (unsigned long long)v->phys_addr);
2639
2640        if (v->flags & VM_IOREMAP)
2641                seq_printf(m, " ioremap");
2642
2643        if (v->flags & VM_ALLOC)
2644                seq_printf(m, " vmalloc");
2645
2646        if (v->flags & VM_MAP)
2647                seq_printf(m, " vmap");
2648
2649        if (v->flags & VM_USERMAP)
2650                seq_printf(m, " user");
2651
2652        if (v->flags & VM_VPAGES)
2653                seq_printf(m, " vpages");
2654
2655        show_numa_info(m, v);
2656        seq_putc(m, '\n');
2657        return 0;
2658}
2659
2660static const struct seq_operations vmalloc_op = {
2661        .start = s_start,
2662        .next = s_next,
2663        .stop = s_stop,
2664        .show = s_show,
2665};
2666
2667static int vmalloc_open(struct inode *inode, struct file *file)
2668{
2669        unsigned int *ptr = NULL;
2670        int ret;
2671
2672        if (IS_ENABLED(CONFIG_NUMA)) {
2673                ptr = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL);
2674                if (ptr == NULL)
2675                        return -ENOMEM;
2676        }
2677        ret = seq_open(file, &vmalloc_op);
2678        if (!ret) {
2679                struct seq_file *m = file->private_data;
2680                m->private = ptr;
2681        } else
2682                kfree(ptr);
2683        return ret;
2684}
2685
2686static const struct file_operations proc_vmalloc_operations = {
2687        .open           = vmalloc_open,
2688        .read           = seq_read,
2689        .llseek         = seq_lseek,
2690        .release        = seq_release_private,
2691};
2692
2693static int __init proc_vmalloc_init(void)
2694{
2695        proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
2696        return 0;
2697}
2698module_init(proc_vmalloc_init);
2699
2700void get_vmalloc_info(struct vmalloc_info *vmi)
2701{
2702        struct vmap_area *va;
2703        unsigned long free_area_size;
2704        unsigned long prev_end;
2705
2706        vmi->used = 0;
2707        vmi->largest_chunk = 0;
2708
2709        prev_end = VMALLOC_START;
2710
2711        spin_lock(&vmap_area_lock);
2712
2713        if (list_empty(&vmap_area_list)) {
2714                vmi->largest_chunk = VMALLOC_TOTAL;
2715                goto out;
2716        }
2717
2718        list_for_each_entry(va, &vmap_area_list, list) {
2719                unsigned long addr = va->va_start;
2720
2721                /*
2722                 * Some archs keep another range for modules in vmalloc space
2723                 */
2724                if (addr < VMALLOC_START)
2725                        continue;
2726                if (addr >= VMALLOC_END)
2727                        break;
2728
2729                if (va->flags & (VM_LAZY_FREE | VM_LAZY_FREEING))
2730                        continue;
2731
2732                vmi->used += (va->va_end - va->va_start);
2733
2734                free_area_size = addr - prev_end;
2735                if (vmi->largest_chunk < free_area_size)
2736                        vmi->largest_chunk = free_area_size;
2737
2738                prev_end = va->va_end;
2739        }
2740
2741        if (VMALLOC_END - prev_end > vmi->largest_chunk)
2742                vmi->largest_chunk = VMALLOC_END - prev_end;
2743
2744out:
2745        spin_unlock(&vmap_area_lock);
2746}
2747#endif
2748
2749
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.