include/linux/hugetlb.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_HUGETLB_H
   3 #define _LINUX_HUGETLB_H
   4
   5 #include <linux/mm_types.h>
   6 #include <linux/mmdebug.h>
   7 #include <linux/fs.h>
   8 #include <linux/hugetlb_inline.h>
   9 #include <linux/cgroup.h>
  10 #include <linux/list.h>
  11 #include <linux/kref.h>
  12 #include <asm/pgtable.h>
  13
  14 struct ctl_table;
  15 struct user_struct;
  16 struct mmu_gather;
  17
  18 #ifndef is_hugepd
  19 /*
  20  * Some architectures requires a hugepage directory format that is
  21  * required to support multiple hugepage sizes. For example
  22  * a4fe3ce76 "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
  23  * introduced the same on powerpc. This allows for a more flexible hugepage
  24  * pagetable layout.
  25  */
  26 typedef struct { unsigned long pd; } hugepd_t;
  27 #define is_hugepd(hugepd) (0)
  28 #define __hugepd(x) ((hugepd_t) { (x) })
  29 static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
  30                               unsigned pdshift, unsigned long end,
  31                               int write, struct page **pages, int *nr)
  32 {
  33         return 0;
  34 }
  35 #else
  36 extern int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
  37                        unsigned pdshift, unsigned long end,
  38                        int write, struct page **pages, int *nr);
  39 #endif
  40
  41
  42 #ifdef CONFIG_HUGETLB_PAGE
  43
  44 #include <linux/mempolicy.h>
  45 #include <linux/shm.h>
  46 #include <asm/tlbflush.h>
  47
  48 struct hugepage_subpool {
  49         spinlock_t lock;
  50         long count;
  51         long max_hpages;        /* Maximum huge pages or -1 if no maximum. */
  52         long used_hpages;       /* Used count against maximum, includes */
  53                                 /* both alloced and reserved pages. */
  54         struct hstate *hstate;
  55         long min_hpages;        /* Minimum huge pages or -1 if no minimum. */
  56         long rsv_hpages;        /* Pages reserved against global pool to */
  57                                 /* sasitfy minimum size. */
  58 };
  59
  60 struct resv_map {
  61         struct kref refs;
  62         spinlock_t lock;
  63         struct list_head regions;
  64         long adds_in_progress;
  65         struct list_head region_cache;
  66         long region_cache_count;
  67 };
  68 extern struct resv_map *resv_map_alloc(void);
  69 void resv_map_release(struct kref *ref);
  70
  71 extern spinlock_t hugetlb_lock;
  72 extern int hugetlb_max_hstate __read_mostly;
  73 #define for_each_hstate(h) \
  74         for ((h) = hstates; (h) < &hstates[hugetlb_max_hstate]; (h)++)
  75
  76 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
  77                                                 long min_hpages);
  78 void hugepage_put_subpool(struct hugepage_subpool *spool);
  79
  80 void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
  81 int hugetlb_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
  82 int hugetlb_overcommit_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
  83 int hugetlb_treat_movable_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
  84
  85 #ifdef CONFIG_NUMA
  86 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int,
  87                                         void __user *, size_t *, loff_t *);
  88 #endif
  89
  90 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
  91 long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
  92                          struct page **, struct vm_area_struct **,
  93                          unsigned long *, unsigned long *, long, unsigned int,
  94                          int *);
  95 void unmap_hugepage_range(struct vm_area_struct *,
  96                           unsigned long, unsigned long, struct page *);
  97 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
  98                           struct vm_area_struct *vma,
  99                           unsigned long start, unsigned long end,
 100                           struct page *ref_page);
 101 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 102                                 unsigned long start, unsigned long end,
 103                                 struct page *ref_page);
 104 void hugetlb_report_meminfo(struct seq_file *);
 105 int hugetlb_report_node_meminfo(int, char *);
 106 void hugetlb_show_meminfo(void);
 107 unsigned long hugetlb_total_pages(void);
 108 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 109                         unsigned long address, unsigned int flags);
 110 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
 111                                 struct vm_area_struct *dst_vma,
 112                                 unsigned long dst_addr,
 113                                 unsigned long src_addr,
 114                                 struct page **pagep);
 115 int hugetlb_reserve_pages(struct inode *inode, long from, long to,
 116                                                 struct vm_area_struct *vma,
 117                                                 vm_flags_t vm_flags);
 118 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
 119                                                 long freed);
 120 bool isolate_huge_page(struct page *page, struct list_head *list);
 121 void putback_active_hugepage(struct page *page);
 122 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason);
 123 void free_huge_page(struct page *page);
 124 void hugetlb_fix_reserve_counts(struct inode *inode);
 125 extern struct mutex *hugetlb_fault_mutex_table;
 126 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
 127                                 struct vm_area_struct *vma,
 128                                 struct address_space *mapping,
 129                                 pgoff_t idx, unsigned long address);
 130
 131 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);
 132
 133 extern int sysctl_hugetlb_shm_group;
 134 extern struct list_head huge_boot_pages;
 135
 136 /* arch callbacks */
 137
 138 pte_t *huge_pte_alloc(struct mm_struct *mm,
 139                         unsigned long addr, unsigned long sz);
 140 pte_t *huge_pte_offset(struct mm_struct *mm,
 141                        unsigned long addr, unsigned long sz);
 142 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
 143 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
 144                               int write);
 145 struct page *follow_huge_pd(struct vm_area_struct *vma,
 146                             unsigned long address, hugepd_t hpd,
 147                             int flags, int pdshift);
 148 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 149                                 pmd_t *pmd, int flags);
 150 struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
 151                                 pud_t *pud, int flags);
 152 struct page *follow_huge_pgd(struct mm_struct *mm, unsigned long address,
 153                              pgd_t *pgd, int flags);
 154
 155 int pmd_huge(pmd_t pmd);
 156 int pud_huge(pud_t pud);
 157 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
 158                 unsigned long address, unsigned long end, pgprot_t newprot);
 159
 160 bool is_hugetlb_entry_migration(pte_t pte);
 161
 162 #else /* !CONFIG_HUGETLB_PAGE */
 163
 164 static inline void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
 165 {
 166 }
 167
 168 static inline unsigned long hugetlb_total_pages(void)
 169 {
 170         return 0;
 171 }
 172
 173 #define follow_hugetlb_page(m,v,p,vs,a,b,i,w,n) ({ BUG(); 0; })
 174 #define follow_huge_addr(mm, addr, write)       ERR_PTR(-EINVAL)
 175 #define copy_hugetlb_page_range(src, dst, vma)  ({ BUG(); 0; })
 176 static inline void hugetlb_report_meminfo(struct seq_file *m)
 177 {
 178 }
 179 #define hugetlb_report_node_meminfo(n, buf)     0
 180 static inline void hugetlb_show_meminfo(void)
 181 {
 182 }
 183 #define follow_huge_pd(vma, addr, hpd, flags, pdshift) NULL
 184 #define follow_huge_pmd(mm, addr, pmd, flags)   NULL
 185 #define follow_huge_pud(mm, addr, pud, flags)   NULL
 186 #define follow_huge_pgd(mm, addr, pgd, flags)   NULL
 187 #define prepare_hugepage_range(file, addr, len) (-EINVAL)
 188 #define pmd_huge(x)     0
 189 #define pud_huge(x)     0
 190 #define is_hugepage_only_range(mm, addr, len)   0
 191 #define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
 192 #define hugetlb_fault(mm, vma, addr, flags)     ({ BUG(); 0; })
 193 #define hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
 194                                 src_addr, pagep)        ({ BUG(); 0; })
 195 #define huge_pte_offset(mm, address, sz)        0
 196
 197 static inline bool isolate_huge_page(struct page *page, struct list_head *list)
 198 {
 199         return false;
 200 }
 201 #define putback_active_hugepage(p)      do {} while (0)
 202 #define move_hugetlb_state(old, new, reason)    do {} while (0)
 203
 204 static inline unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
 205                 unsigned long address, unsigned long end, pgprot_t newprot)
 206 {
 207         return 0;
 208 }
 209
 210 static inline void __unmap_hugepage_range_final(struct mmu_gather *tlb,
 211                         struct vm_area_struct *vma, unsigned long start,
 212                         unsigned long end, struct page *ref_page)
 213 {
 214         BUG();
 215 }
 216
 217 static inline void __unmap_hugepage_range(struct mmu_gather *tlb,
 218                         struct vm_area_struct *vma, unsigned long start,
 219                         unsigned long end, struct page *ref_page)
 220 {
 221         BUG();
 222 }
 223
 224 #endif /* !CONFIG_HUGETLB_PAGE */
 225 /*
 226  * hugepages at page global directory. If arch support
 227  * hugepages at pgd level, they need to define this.
 228  */
 229 #ifndef pgd_huge
 230 #define pgd_huge(x)     0
 231 #endif
 232 #ifndef p4d_huge
 233 #define p4d_huge(x)     0
 234 #endif
 235
 236 #ifndef pgd_write
 237 static inline int pgd_write(pgd_t pgd)
 238 {
 239         BUG();
 240         return 0;
 241 }
 242 #endif
 243
 244 #define HUGETLB_ANON_FILE "anon_hugepage"
 245
 246 enum {
 247         /*
 248          * The file will be used as an shm file so shmfs accounting rules
 249          * apply
 250          */
 251         HUGETLB_SHMFS_INODE     = 1,
 252         /*
 253          * The file is being created on the internal vfs mount and shmfs
 254          * accounting rules do not apply
 255          */
 256         HUGETLB_ANONHUGE_INODE  = 2,
 257 };
 258
 259 #ifdef CONFIG_HUGETLBFS
 260 struct hugetlbfs_sb_info {
 261         long    max_inodes;   /* inodes allowed */
 262         long    free_inodes;  /* inodes free */
 263         spinlock_t      stat_lock;
 264         struct hstate *hstate;
 265         struct hugepage_subpool *spool;
 266         kuid_t  uid;
 267         kgid_t  gid;
 268         umode_t mode;
 269 };
 270
 271 static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
 272 {
 273         return sb->s_fs_info;
 274 }
 275
 276 struct hugetlbfs_inode_info {
 277         struct shared_policy policy;
 278         struct inode vfs_inode;
 279         unsigned int seals;
 280 };
 281
 282 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
 283 {
 284         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
 285 }
 286
 287 extern const struct file_operations hugetlbfs_file_operations;
 288 extern const struct vm_operations_struct hugetlb_vm_ops;
 289 struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct,
 290                                 struct user_struct **user, int creat_flags,
 291                                 int page_size_log);
 292
 293 static inline bool is_file_hugepages(struct file *file)
 294 {
 295         if (file->f_op == &hugetlbfs_file_operations)
 296                 return true;
 297
 298         return is_file_shm_hugepages(file);
 299 }
 300
 301
 302 #else /* !CONFIG_HUGETLBFS */
 303
 304 #define is_file_hugepages(file)                 false
 305 static inline struct file *
 306 hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
 307                 struct user_struct **user, int creat_flags,
 308                 int page_size_log)
 309 {
 310         return ERR_PTR(-ENOSYS);
 311 }
 312
 313 #endif /* !CONFIG_HUGETLBFS */
 314
 315 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 316 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 317                                         unsigned long len, unsigned long pgoff,
 318                                         unsigned long flags);
 319 #endif /* HAVE_ARCH_HUGETLB_UNMAPPED_AREA */
 320
 321 #ifdef CONFIG_HUGETLB_PAGE
 322
 323 #define HSTATE_NAME_LEN 32
 324 /* Defines one hugetlb page size */
 325 struct hstate {
 326         int next_nid_to_alloc;
 327         int next_nid_to_free;
 328         unsigned int order;
 329         unsigned long mask;
 330         unsigned long max_huge_pages;
 331         unsigned long nr_huge_pages;
 332         unsigned long free_huge_pages;
 333         unsigned long resv_huge_pages;
 334         unsigned long surplus_huge_pages;
 335         unsigned long nr_overcommit_huge_pages;
 336         struct list_head hugepage_activelist;
 337         struct list_head hugepage_freelists[MAX_NUMNODES];
 338         unsigned int nr_huge_pages_node[MAX_NUMNODES];
 339         unsigned int free_huge_pages_node[MAX_NUMNODES];
 340         unsigned int surplus_huge_pages_node[MAX_NUMNODES];
 341 #ifdef CONFIG_CGROUP_HUGETLB
 342         /* cgroup control files */
 343         struct cftype cgroup_files[5];
 344 #endif
 345         char name[HSTATE_NAME_LEN];
 346 };
 347
 348 struct huge_bootmem_page {
 349         struct list_head list;
 350         struct hstate *hstate;
 351 #ifdef CONFIG_HIGHMEM
 352         phys_addr_t phys;
 353 #endif
 354 };
 355
 356 struct page *alloc_huge_page(struct vm_area_struct *vma,
 357                                 unsigned long addr, int avoid_reserve);
 358 struct page *alloc_huge_page_node(struct hstate *h, int nid);
 359 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
 360                                 nodemask_t *nmask);
 361 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
 362                                 unsigned long address);
 363 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
 364                         pgoff_t idx);
 365
 366 /* arch callback */
 367 int __init __alloc_bootmem_huge_page(struct hstate *h);
 368 int __init alloc_bootmem_huge_page(struct hstate *h);
 369
 370 void __init hugetlb_bad_size(void);
 371 void __init hugetlb_add_hstate(unsigned order);
 372 struct hstate *size_to_hstate(unsigned long size);
 373
 374 #ifndef HUGE_MAX_HSTATE
 375 #define HUGE_MAX_HSTATE 1
 376 #endif
 377
 378 extern struct hstate hstates[HUGE_MAX_HSTATE];
 379 extern unsigned int default_hstate_idx;
 380
 381 #define default_hstate (hstates[default_hstate_idx])
 382
 383 static inline struct hstate *hstate_inode(struct inode *i)
 384 {
 385         return HUGETLBFS_SB(i->i_sb)->hstate;
 386 }
 387
 388 static inline struct hstate *hstate_file(struct file *f)
 389 {
 390         return hstate_inode(file_inode(f));
 391 }
 392
 393 static inline struct hstate *hstate_sizelog(int page_size_log)
 394 {
 395         if (!page_size_log)
 396                 return &default_hstate;
 397
 398         return size_to_hstate(1UL << page_size_log);
 399 }
 400
 401 static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
 402 {
 403         return hstate_file(vma->vm_file);
 404 }
 405
 406 static inline unsigned long huge_page_size(struct hstate *h)
 407 {
 408         return (unsigned long)PAGE_SIZE << h->order;
 409 }
 410
 411 extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma);
 412
 413 extern unsigned long vma_mmu_pagesize(struct vm_area_struct *vma);
 414
 415 static inline unsigned long huge_page_mask(struct hstate *h)
 416 {
 417         return h->mask;
 418 }
 419
 420 static inline unsigned int huge_page_order(struct hstate *h)
 421 {
 422         return h->order;
 423 }
 424
 425 static inline unsigned huge_page_shift(struct hstate *h)
 426 {
 427         return h->order + PAGE_SHIFT;
 428 }
 429
 430 static inline bool hstate_is_gigantic(struct hstate *h)
 431 {
 432         return huge_page_order(h) >= MAX_ORDER;
 433 }
 434
 435 static inline unsigned int pages_per_huge_page(struct hstate *h)
 436 {
 437         return 1 << h->order;
 438 }
 439
 440 static inline unsigned int blocks_per_huge_page(struct hstate *h)
 441 {
 442         return huge_page_size(h) / 512;
 443 }
 444
 445 #include <asm/hugetlb.h>
 446
 447 #ifndef arch_make_huge_pte
 448 static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 449                                        struct page *page, int writable)
 450 {
 451         return entry;
 452 }
 453 #endif
 454
 455 static inline struct hstate *page_hstate(struct page *page)
 456 {
 457         VM_BUG_ON_PAGE(!PageHuge(page), page);
 458         return size_to_hstate(PAGE_SIZE << compound_order(page));
 459 }
 460
 461 static inline unsigned hstate_index_to_shift(unsigned index)
 462 {
 463         return hstates[index].order + PAGE_SHIFT;
 464 }
 465
 466 static inline int hstate_index(struct hstate *h)
 467 {
 468         return h - hstates;
 469 }
 470
 471 pgoff_t __basepage_index(struct page *page);
 472
 473 /* Return page->index in PAGE_SIZE units */
 474 static inline pgoff_t basepage_index(struct page *page)
 475 {
 476         if (!PageCompound(page))
 477                 return page->index;
 478
 479         return __basepage_index(page);
 480 }
 481
 482 extern int dissolve_free_huge_page(struct page *page);
 483 extern int dissolve_free_huge_pages(unsigned long start_pfn,
 484                                     unsigned long end_pfn);
 485 static inline bool hugepage_migration_supported(struct hstate *h)
 486 {
 487 #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
 488         if ((huge_page_shift(h) == PMD_SHIFT) ||
 489                 (huge_page_shift(h) == PGDIR_SHIFT))
 490                 return true;
 491         else
 492                 return false;
 493 #else
 494         return false;
 495 #endif
 496 }
 497
 498 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 499                                            struct mm_struct *mm, pte_t *pte)
 500 {
 501         if (huge_page_size(h) == PMD_SIZE)
 502                 return pmd_lockptr(mm, (pmd_t *) pte);
 503         VM_BUG_ON(huge_page_size(h) == PAGE_SIZE);
 504         return &mm->page_table_lock;
 505 }
 506
 507 #ifndef hugepages_supported
 508 /*
 509  * Some platform decide whether they support huge pages at boot
 510  * time. Some of them, such as powerpc, set HPAGE_SHIFT to 0
 511  * when there is no such support
 512  */
 513 #define hugepages_supported() (HPAGE_SHIFT != 0)
 514 #endif
 515
 516 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
 517
 518 static inline void hugetlb_count_add(long l, struct mm_struct *mm)
 519 {
 520         atomic_long_add(l, &mm->hugetlb_usage);
 521 }
 522
 523 static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
 524 {
 525         atomic_long_sub(l, &mm->hugetlb_usage);
 526 }
 527
 528 #ifndef set_huge_swap_pte_at
 529 static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
 530                                         pte_t *ptep, pte_t pte, unsigned long sz)
 531 {
 532         set_huge_pte_at(mm, addr, ptep, pte);
 533 }
 534 #endif
 535 #else   /* CONFIG_HUGETLB_PAGE */
 536 struct hstate {};
 537 #define alloc_huge_page(v, a, r) NULL
 538 #define alloc_huge_page_node(h, nid) NULL
 539 #define alloc_huge_page_nodemask(h, preferred_nid, nmask) NULL
 540 #define alloc_huge_page_vma(h, vma, address) NULL
 541 #define alloc_bootmem_huge_page(h) NULL
 542 #define hstate_file(f) NULL
 543 #define hstate_sizelog(s) NULL
 544 #define hstate_vma(v) NULL
 545 #define hstate_inode(i) NULL
 546 #define page_hstate(page) NULL
 547 #define huge_page_size(h) PAGE_SIZE
 548 #define huge_page_mask(h) PAGE_MASK
 549 #define vma_kernel_pagesize(v) PAGE_SIZE
 550 #define vma_mmu_pagesize(v) PAGE_SIZE
 551 #define huge_page_order(h) 0
 552 #define huge_page_shift(h) PAGE_SHIFT
 553 static inline bool hstate_is_gigantic(struct hstate *h)
 554 {
 555         return false;
 556 }
 557
 558 static inline unsigned int pages_per_huge_page(struct hstate *h)
 559 {
 560         return 1;
 561 }
 562
 563 static inline unsigned hstate_index_to_shift(unsigned index)
 564 {
 565         return 0;
 566 }
 567
 568 static inline int hstate_index(struct hstate *h)
 569 {
 570         return 0;
 571 }
 572
 573 static inline pgoff_t basepage_index(struct page *page)
 574 {
 575         return page->index;
 576 }
 577
 578 static inline int dissolve_free_huge_page(struct page *page)
 579 {
 580         return 0;
 581 }
 582
 583 static inline int dissolve_free_huge_pages(unsigned long start_pfn,
 584                                            unsigned long end_pfn)
 585 {
 586         return 0;
 587 }
 588
 589 static inline bool hugepage_migration_supported(struct hstate *h)
 590 {
 591         return false;
 592 }
 593
 594 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 595                                            struct mm_struct *mm, pte_t *pte)
 596 {
 597         return &mm->page_table_lock;
 598 }
 599
 600 static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
 601 {
 602 }
 603
 604 static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
 605 {
 606 }
 607
 608 static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
 609                                         pte_t *ptep, pte_t pte, unsigned long sz)
 610 {
 611 }
 612 #endif  /* CONFIG_HUGETLB_PAGE */
 613
 614 static inline spinlock_t *huge_pte_lock(struct hstate *h,
 615                                         struct mm_struct *mm, pte_t *pte)
 616 {
 617         spinlock_t *ptl;
 618
 619         ptl = huge_pte_lockptr(h, mm, pte);
 620         spin_lock(ptl);
 621         return ptl;
 622 }
 623
 624 #endif /* _LINUX_HUGETLB_H */