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Linux/fs/hugetlbfs/inode.c

  1 /*
  2  * hugetlbpage-backed filesystem.  Based on ramfs.
  3  *
  4  * Nadia Yvette Chambers, 2002
  5  *
  6  * Copyright (C) 2002 Linus Torvalds.
  7  */
  8 
  9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 10 
 11 #include <linux/module.h>
 12 #include <linux/thread_info.h>
 13 #include <asm/current.h>
 14 #include <linux/sched.h>                /* remove ASAP */
 15 #include <linux/falloc.h>
 16 #include <linux/fs.h>
 17 #include <linux/mount.h>
 18 #include <linux/file.h>
 19 #include <linux/kernel.h>
 20 #include <linux/writeback.h>
 21 #include <linux/pagemap.h>
 22 #include <linux/highmem.h>
 23 #include <linux/init.h>
 24 #include <linux/string.h>
 25 #include <linux/capability.h>
 26 #include <linux/ctype.h>
 27 #include <linux/backing-dev.h>
 28 #include <linux/hugetlb.h>
 29 #include <linux/pagevec.h>
 30 #include <linux/parser.h>
 31 #include <linux/mman.h>
 32 #include <linux/slab.h>
 33 #include <linux/dnotify.h>
 34 #include <linux/statfs.h>
 35 #include <linux/security.h>
 36 #include <linux/magic.h>
 37 #include <linux/migrate.h>
 38 #include <linux/uio.h>
 39 
 40 #include <asm/uaccess.h>
 41 
 42 static const struct super_operations hugetlbfs_ops;
 43 static const struct address_space_operations hugetlbfs_aops;
 44 const struct file_operations hugetlbfs_file_operations;
 45 static const struct inode_operations hugetlbfs_dir_inode_operations;
 46 static const struct inode_operations hugetlbfs_inode_operations;
 47 
 48 struct hugetlbfs_config {
 49         kuid_t   uid;
 50         kgid_t   gid;
 51         umode_t mode;
 52         long    max_hpages;
 53         long    nr_inodes;
 54         struct hstate *hstate;
 55         long    min_hpages;
 56 };
 57 
 58 struct hugetlbfs_inode_info {
 59         struct shared_policy policy;
 60         struct inode vfs_inode;
 61 };
 62 
 63 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
 64 {
 65         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
 66 }
 67 
 68 int sysctl_hugetlb_shm_group;
 69 
 70 enum {
 71         Opt_size, Opt_nr_inodes,
 72         Opt_mode, Opt_uid, Opt_gid,
 73         Opt_pagesize, Opt_min_size,
 74         Opt_err,
 75 };
 76 
 77 static const match_table_t tokens = {
 78         {Opt_size,      "size=%s"},
 79         {Opt_nr_inodes, "nr_inodes=%s"},
 80         {Opt_mode,      "mode=%o"},
 81         {Opt_uid,       "uid=%u"},
 82         {Opt_gid,       "gid=%u"},
 83         {Opt_pagesize,  "pagesize=%s"},
 84         {Opt_min_size,  "min_size=%s"},
 85         {Opt_err,       NULL},
 86 };
 87 
 88 #ifdef CONFIG_NUMA
 89 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
 90                                         struct inode *inode, pgoff_t index)
 91 {
 92         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
 93                                                         index);
 94 }
 95 
 96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
 97 {
 98         mpol_cond_put(vma->vm_policy);
 99 }
100 #else
101 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
102                                         struct inode *inode, pgoff_t index)
103 {
104 }
105 
106 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
107 {
108 }
109 #endif
110 
111 static void huge_pagevec_release(struct pagevec *pvec)
112 {
113         int i;
114 
115         for (i = 0; i < pagevec_count(pvec); ++i)
116                 put_page(pvec->pages[i]);
117 
118         pagevec_reinit(pvec);
119 }
120 
121 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
122 {
123         struct inode *inode = file_inode(file);
124         loff_t len, vma_len;
125         int ret;
126         struct hstate *h = hstate_file(file);
127 
128         /*
129          * vma address alignment (but not the pgoff alignment) has
130          * already been checked by prepare_hugepage_range.  If you add
131          * any error returns here, do so after setting VM_HUGETLB, so
132          * is_vm_hugetlb_page tests below unmap_region go the right
133          * way when do_mmap_pgoff unwinds (may be important on powerpc
134          * and ia64).
135          */
136         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
137         vma->vm_ops = &hugetlb_vm_ops;
138 
139         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
140                 return -EINVAL;
141 
142         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
143 
144         mutex_lock(&inode->i_mutex);
145         file_accessed(file);
146 
147         ret = -ENOMEM;
148         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
149 
150         if (hugetlb_reserve_pages(inode,
151                                 vma->vm_pgoff >> huge_page_order(h),
152                                 len >> huge_page_shift(h), vma,
153                                 vma->vm_flags))
154                 goto out;
155 
156         ret = 0;
157         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
158                 inode->i_size = len;
159 out:
160         mutex_unlock(&inode->i_mutex);
161 
162         return ret;
163 }
164 
165 /*
166  * Called under down_write(mmap_sem).
167  */
168 
169 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
170 static unsigned long
171 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
172                 unsigned long len, unsigned long pgoff, unsigned long flags)
173 {
174         struct mm_struct *mm = current->mm;
175         struct vm_area_struct *vma;
176         struct hstate *h = hstate_file(file);
177         struct vm_unmapped_area_info info;
178 
179         if (len & ~huge_page_mask(h))
180                 return -EINVAL;
181         if (len > TASK_SIZE)
182                 return -ENOMEM;
183 
184         if (flags & MAP_FIXED) {
185                 if (prepare_hugepage_range(file, addr, len))
186                         return -EINVAL;
187                 return addr;
188         }
189 
190         if (addr) {
191                 addr = ALIGN(addr, huge_page_size(h));
192                 vma = find_vma(mm, addr);
193                 if (TASK_SIZE - len >= addr &&
194                     (!vma || addr + len <= vma->vm_start))
195                         return addr;
196         }
197 
198         info.flags = 0;
199         info.length = len;
200         info.low_limit = TASK_UNMAPPED_BASE;
201         info.high_limit = TASK_SIZE;
202         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
203         info.align_offset = 0;
204         return vm_unmapped_area(&info);
205 }
206 #endif
207 
208 static size_t
209 hugetlbfs_read_actor(struct page *page, unsigned long offset,
210                         struct iov_iter *to, unsigned long size)
211 {
212         size_t copied = 0;
213         int i, chunksize;
214 
215         /* Find which 4k chunk and offset with in that chunk */
216         i = offset >> PAGE_CACHE_SHIFT;
217         offset = offset & ~PAGE_CACHE_MASK;
218 
219         while (size) {
220                 size_t n;
221                 chunksize = PAGE_CACHE_SIZE;
222                 if (offset)
223                         chunksize -= offset;
224                 if (chunksize > size)
225                         chunksize = size;
226                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
227                 copied += n;
228                 if (n != chunksize)
229                         return copied;
230                 offset = 0;
231                 size -= chunksize;
232                 i++;
233         }
234         return copied;
235 }
236 
237 /*
238  * Support for read() - Find the page attached to f_mapping and copy out the
239  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
240  * since it has PAGE_CACHE_SIZE assumptions.
241  */
242 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
243 {
244         struct file *file = iocb->ki_filp;
245         struct hstate *h = hstate_file(file);
246         struct address_space *mapping = file->f_mapping;
247         struct inode *inode = mapping->host;
248         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
249         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
250         unsigned long end_index;
251         loff_t isize;
252         ssize_t retval = 0;
253 
254         while (iov_iter_count(to)) {
255                 struct page *page;
256                 size_t nr, copied;
257 
258                 /* nr is the maximum number of bytes to copy from this page */
259                 nr = huge_page_size(h);
260                 isize = i_size_read(inode);
261                 if (!isize)
262                         break;
263                 end_index = (isize - 1) >> huge_page_shift(h);
264                 if (index > end_index)
265                         break;
266                 if (index == end_index) {
267                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
268                         if (nr <= offset)
269                                 break;
270                 }
271                 nr = nr - offset;
272 
273                 /* Find the page */
274                 page = find_lock_page(mapping, index);
275                 if (unlikely(page == NULL)) {
276                         /*
277                          * We have a HOLE, zero out the user-buffer for the
278                          * length of the hole or request.
279                          */
280                         copied = iov_iter_zero(nr, to);
281                 } else {
282                         unlock_page(page);
283 
284                         /*
285                          * We have the page, copy it to user space buffer.
286                          */
287                         copied = hugetlbfs_read_actor(page, offset, to, nr);
288                         page_cache_release(page);
289                 }
290                 offset += copied;
291                 retval += copied;
292                 if (copied != nr && iov_iter_count(to)) {
293                         if (!retval)
294                                 retval = -EFAULT;
295                         break;
296                 }
297                 index += offset >> huge_page_shift(h);
298                 offset &= ~huge_page_mask(h);
299         }
300         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
301         return retval;
302 }
303 
304 static int hugetlbfs_write_begin(struct file *file,
305                         struct address_space *mapping,
306                         loff_t pos, unsigned len, unsigned flags,
307                         struct page **pagep, void **fsdata)
308 {
309         return -EINVAL;
310 }
311 
312 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
313                         loff_t pos, unsigned len, unsigned copied,
314                         struct page *page, void *fsdata)
315 {
316         BUG();
317         return -EINVAL;
318 }
319 
320 static void remove_huge_page(struct page *page)
321 {
322         ClearPageDirty(page);
323         ClearPageUptodate(page);
324         delete_from_page_cache(page);
325 }
326 
327 
328 /*
329  * remove_inode_hugepages handles two distinct cases: truncation and hole
330  * punch.  There are subtle differences in operation for each case.
331 
332  * truncation is indicated by end of range being LLONG_MAX
333  *      In this case, we first scan the range and release found pages.
334  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
335  *      maps and global counts.  Page faults can not race with truncation
336  *      in this routine.  hugetlb_no_page() prevents page faults in the
337  *      truncated range.  It checks i_size before allocation, and again after
338  *      with the page table lock for the page held.  The same lock must be
339  *      acquired to unmap a page.
340  * hole punch is indicated if end is not LLONG_MAX
341  *      In the hole punch case we scan the range and release found pages.
342  *      Only when releasing a page is the associated region/reserv map
343  *      deleted.  The region/reserv map for ranges without associated
344  *      pages are not modified.  Page faults can race with hole punch.
345  *      This is indicated if we find a mapped page.
346  * Note: If the passed end of range value is beyond the end of file, but
347  * not LLONG_MAX this routine still performs a hole punch operation.
348  */
349 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
350                                    loff_t lend)
351 {
352         struct hstate *h = hstate_inode(inode);
353         struct address_space *mapping = &inode->i_data;
354         const pgoff_t start = lstart >> huge_page_shift(h);
355         const pgoff_t end = lend >> huge_page_shift(h);
356         struct vm_area_struct pseudo_vma;
357         struct pagevec pvec;
358         pgoff_t next;
359         int i, freed = 0;
360         long lookup_nr = PAGEVEC_SIZE;
361         bool truncate_op = (lend == LLONG_MAX);
362 
363         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
364         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
365         pagevec_init(&pvec, 0);
366         next = start;
367         while (next < end) {
368                 /*
369                  * Don't grab more pages than the number left in the range.
370                  */
371                 if (end - next < lookup_nr)
372                         lookup_nr = end - next;
373 
374                 /*
375                  * When no more pages are found, we are done.
376                  */
377                 if (!pagevec_lookup(&pvec, mapping, next, lookup_nr))
378                         break;
379 
380                 for (i = 0; i < pagevec_count(&pvec); ++i) {
381                         struct page *page = pvec.pages[i];
382                         u32 hash;
383 
384                         /*
385                          * The page (index) could be beyond end.  This is
386                          * only possible in the punch hole case as end is
387                          * max page offset in the truncate case.
388                          */
389                         next = page->index;
390                         if (next >= end)
391                                 break;
392 
393                         hash = hugetlb_fault_mutex_hash(h, current->mm,
394                                                         &pseudo_vma,
395                                                         mapping, next, 0);
396                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
397 
398                         lock_page(page);
399                         if (likely(!page_mapped(page))) {
400                                 bool rsv_on_error = !PagePrivate(page);
401                                 /*
402                                  * We must free the huge page and remove
403                                  * from page cache (remove_huge_page) BEFORE
404                                  * removing the region/reserve map
405                                  * (hugetlb_unreserve_pages).  In rare out
406                                  * of memory conditions, removal of the
407                                  * region/reserve map could fail.  Before
408                                  * free'ing the page, note PagePrivate which
409                                  * is used in case of error.
410                                  */
411                                 remove_huge_page(page);
412                                 freed++;
413                                 if (!truncate_op) {
414                                         if (unlikely(hugetlb_unreserve_pages(
415                                                         inode, next,
416                                                         next + 1, 1)))
417                                                 hugetlb_fix_reserve_counts(
418                                                         inode, rsv_on_error);
419                                 }
420                         } else {
421                                 /*
422                                  * If page is mapped, it was faulted in after
423                                  * being unmapped.  It indicates a race between
424                                  * hole punch and page fault.  Do nothing in
425                                  * this case.  Getting here in a truncate
426                                  * operation is a bug.
427                                  */
428                                 BUG_ON(truncate_op);
429                         }
430 
431                         unlock_page(page);
432                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
433                 }
434                 ++next;
435                 huge_pagevec_release(&pvec);
436                 cond_resched();
437         }
438 
439         if (truncate_op)
440                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
441 }
442 
443 static void hugetlbfs_evict_inode(struct inode *inode)
444 {
445         struct resv_map *resv_map;
446 
447         remove_inode_hugepages(inode, 0, LLONG_MAX);
448         resv_map = (struct resv_map *)inode->i_mapping->private_data;
449         /* root inode doesn't have the resv_map, so we should check it */
450         if (resv_map)
451                 resv_map_release(&resv_map->refs);
452         clear_inode(inode);
453 }
454 
455 static inline void
456 hugetlb_vmdelete_list(struct rb_root *root, pgoff_t start, pgoff_t end)
457 {
458         struct vm_area_struct *vma;
459 
460         /*
461          * end == 0 indicates that the entire range after
462          * start should be unmapped.
463          */
464         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
465                 unsigned long v_offset;
466 
467                 /*
468                  * Can the expression below overflow on 32-bit arches?
469                  * No, because the interval tree returns us only those vmas
470                  * which overlap the truncated area starting at pgoff,
471                  * and no vma on a 32-bit arch can span beyond the 4GB.
472                  */
473                 if (vma->vm_pgoff < start)
474                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
475                 else
476                         v_offset = 0;
477 
478                 if (end) {
479                         end = ((end - start) << PAGE_SHIFT) +
480                                vma->vm_start + v_offset;
481                         if (end > vma->vm_end)
482                                 end = vma->vm_end;
483                 } else
484                         end = vma->vm_end;
485 
486                 unmap_hugepage_range(vma, vma->vm_start + v_offset, end, NULL);
487         }
488 }
489 
490 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
491 {
492         pgoff_t pgoff;
493         struct address_space *mapping = inode->i_mapping;
494         struct hstate *h = hstate_inode(inode);
495 
496         BUG_ON(offset & ~huge_page_mask(h));
497         pgoff = offset >> PAGE_SHIFT;
498 
499         i_size_write(inode, offset);
500         i_mmap_lock_write(mapping);
501         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
502                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
503         i_mmap_unlock_write(mapping);
504         remove_inode_hugepages(inode, offset, LLONG_MAX);
505         return 0;
506 }
507 
508 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
509 {
510         struct hstate *h = hstate_inode(inode);
511         loff_t hpage_size = huge_page_size(h);
512         loff_t hole_start, hole_end;
513 
514         /*
515          * For hole punch round up the beginning offset of the hole and
516          * round down the end.
517          */
518         hole_start = round_up(offset, hpage_size);
519         hole_end = round_down(offset + len, hpage_size);
520 
521         if (hole_end > hole_start) {
522                 struct address_space *mapping = inode->i_mapping;
523 
524                 mutex_lock(&inode->i_mutex);
525                 i_mmap_lock_write(mapping);
526                 if (!RB_EMPTY_ROOT(&mapping->i_mmap))
527                         hugetlb_vmdelete_list(&mapping->i_mmap,
528                                                 hole_start >> PAGE_SHIFT,
529                                                 hole_end  >> PAGE_SHIFT);
530                 i_mmap_unlock_write(mapping);
531                 remove_inode_hugepages(inode, hole_start, hole_end);
532                 mutex_unlock(&inode->i_mutex);
533         }
534 
535         return 0;
536 }
537 
538 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
539                                 loff_t len)
540 {
541         struct inode *inode = file_inode(file);
542         struct address_space *mapping = inode->i_mapping;
543         struct hstate *h = hstate_inode(inode);
544         struct vm_area_struct pseudo_vma;
545         struct mm_struct *mm = current->mm;
546         loff_t hpage_size = huge_page_size(h);
547         unsigned long hpage_shift = huge_page_shift(h);
548         pgoff_t start, index, end;
549         int error;
550         u32 hash;
551 
552         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
553                 return -EOPNOTSUPP;
554 
555         if (mode & FALLOC_FL_PUNCH_HOLE)
556                 return hugetlbfs_punch_hole(inode, offset, len);
557 
558         /*
559          * Default preallocate case.
560          * For this range, start is rounded down and end is rounded up
561          * as well as being converted to page offsets.
562          */
563         start = offset >> hpage_shift;
564         end = (offset + len + hpage_size - 1) >> hpage_shift;
565 
566         mutex_lock(&inode->i_mutex);
567 
568         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
569         error = inode_newsize_ok(inode, offset + len);
570         if (error)
571                 goto out;
572 
573         /*
574          * Initialize a pseudo vma as this is required by the huge page
575          * allocation routines.  If NUMA is configured, use page index
576          * as input to create an allocation policy.
577          */
578         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
579         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
580         pseudo_vma.vm_file = file;
581 
582         for (index = start; index < end; index++) {
583                 /*
584                  * This is supposed to be the vaddr where the page is being
585                  * faulted in, but we have no vaddr here.
586                  */
587                 struct page *page;
588                 unsigned long addr;
589                 int avoid_reserve = 0;
590 
591                 cond_resched();
592 
593                 /*
594                  * fallocate(2) manpage permits EINTR; we may have been
595                  * interrupted because we are using up too much memory.
596                  */
597                 if (signal_pending(current)) {
598                         error = -EINTR;
599                         break;
600                 }
601 
602                 /* Set numa allocation policy based on index */
603                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
604 
605                 /* addr is the offset within the file (zero based) */
606                 addr = index * hpage_size;
607 
608                 /* mutex taken here, fault path and hole punch */
609                 hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
610                                                 index, addr);
611                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
612 
613                 /* See if already present in mapping to avoid alloc/free */
614                 page = find_get_page(mapping, index);
615                 if (page) {
616                         put_page(page);
617                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
618                         hugetlb_drop_vma_policy(&pseudo_vma);
619                         continue;
620                 }
621 
622                 /* Allocate page and add to page cache */
623                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
624                 hugetlb_drop_vma_policy(&pseudo_vma);
625                 if (IS_ERR(page)) {
626                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
627                         error = PTR_ERR(page);
628                         goto out;
629                 }
630                 clear_huge_page(page, addr, pages_per_huge_page(h));
631                 __SetPageUptodate(page);
632                 error = huge_add_to_page_cache(page, mapping, index);
633                 if (unlikely(error)) {
634                         put_page(page);
635                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
636                         goto out;
637                 }
638 
639                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
640 
641                 /*
642                  * page_put due to reference from alloc_huge_page()
643                  * unlock_page because locked by add_to_page_cache()
644                  */
645                 put_page(page);
646                 unlock_page(page);
647         }
648 
649         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
650                 i_size_write(inode, offset + len);
651         inode->i_ctime = CURRENT_TIME;
652 out:
653         mutex_unlock(&inode->i_mutex);
654         return error;
655 }
656 
657 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
658 {
659         struct inode *inode = d_inode(dentry);
660         struct hstate *h = hstate_inode(inode);
661         int error;
662         unsigned int ia_valid = attr->ia_valid;
663 
664         BUG_ON(!inode);
665 
666         error = inode_change_ok(inode, attr);
667         if (error)
668                 return error;
669 
670         if (ia_valid & ATTR_SIZE) {
671                 error = -EINVAL;
672                 if (attr->ia_size & ~huge_page_mask(h))
673                         return -EINVAL;
674                 error = hugetlb_vmtruncate(inode, attr->ia_size);
675                 if (error)
676                         return error;
677         }
678 
679         setattr_copy(inode, attr);
680         mark_inode_dirty(inode);
681         return 0;
682 }
683 
684 static struct inode *hugetlbfs_get_root(struct super_block *sb,
685                                         struct hugetlbfs_config *config)
686 {
687         struct inode *inode;
688 
689         inode = new_inode(sb);
690         if (inode) {
691                 struct hugetlbfs_inode_info *info;
692                 inode->i_ino = get_next_ino();
693                 inode->i_mode = S_IFDIR | config->mode;
694                 inode->i_uid = config->uid;
695                 inode->i_gid = config->gid;
696                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
697                 info = HUGETLBFS_I(inode);
698                 mpol_shared_policy_init(&info->policy, NULL);
699                 inode->i_op = &hugetlbfs_dir_inode_operations;
700                 inode->i_fop = &simple_dir_operations;
701                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
702                 inc_nlink(inode);
703                 lockdep_annotate_inode_mutex_key(inode);
704         }
705         return inode;
706 }
707 
708 /*
709  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
710  * be taken from reclaim -- unlike regular filesystems. This needs an
711  * annotation because huge_pmd_share() does an allocation under
712  * i_mmap_rwsem.
713  */
714 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
715 
716 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
717                                         struct inode *dir,
718                                         umode_t mode, dev_t dev)
719 {
720         struct inode *inode;
721         struct resv_map *resv_map;
722 
723         resv_map = resv_map_alloc();
724         if (!resv_map)
725                 return NULL;
726 
727         inode = new_inode(sb);
728         if (inode) {
729                 struct hugetlbfs_inode_info *info;
730                 inode->i_ino = get_next_ino();
731                 inode_init_owner(inode, dir, mode);
732                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
733                                 &hugetlbfs_i_mmap_rwsem_key);
734                 inode->i_mapping->a_ops = &hugetlbfs_aops;
735                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
736                 inode->i_mapping->private_data = resv_map;
737                 info = HUGETLBFS_I(inode);
738                 /*
739                  * The policy is initialized here even if we are creating a
740                  * private inode because initialization simply creates an
741                  * an empty rb tree and calls spin_lock_init(), later when we
742                  * call mpol_free_shared_policy() it will just return because
743                  * the rb tree will still be empty.
744                  */
745                 mpol_shared_policy_init(&info->policy, NULL);
746                 switch (mode & S_IFMT) {
747                 default:
748                         init_special_inode(inode, mode, dev);
749                         break;
750                 case S_IFREG:
751                         inode->i_op = &hugetlbfs_inode_operations;
752                         inode->i_fop = &hugetlbfs_file_operations;
753                         break;
754                 case S_IFDIR:
755                         inode->i_op = &hugetlbfs_dir_inode_operations;
756                         inode->i_fop = &simple_dir_operations;
757 
758                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
759                         inc_nlink(inode);
760                         break;
761                 case S_IFLNK:
762                         inode->i_op = &page_symlink_inode_operations;
763                         break;
764                 }
765                 lockdep_annotate_inode_mutex_key(inode);
766         } else
767                 kref_put(&resv_map->refs, resv_map_release);
768 
769         return inode;
770 }
771 
772 /*
773  * File creation. Allocate an inode, and we're done..
774  */
775 static int hugetlbfs_mknod(struct inode *dir,
776                         struct dentry *dentry, umode_t mode, dev_t dev)
777 {
778         struct inode *inode;
779         int error = -ENOSPC;
780 
781         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
782         if (inode) {
783                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
784                 d_instantiate(dentry, inode);
785                 dget(dentry);   /* Extra count - pin the dentry in core */
786                 error = 0;
787         }
788         return error;
789 }
790 
791 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
792 {
793         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
794         if (!retval)
795                 inc_nlink(dir);
796         return retval;
797 }
798 
799 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
800 {
801         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
802 }
803 
804 static int hugetlbfs_symlink(struct inode *dir,
805                         struct dentry *dentry, const char *symname)
806 {
807         struct inode *inode;
808         int error = -ENOSPC;
809 
810         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
811         if (inode) {
812                 int l = strlen(symname)+1;
813                 error = page_symlink(inode, symname, l);
814                 if (!error) {
815                         d_instantiate(dentry, inode);
816                         dget(dentry);
817                 } else
818                         iput(inode);
819         }
820         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
821 
822         return error;
823 }
824 
825 /*
826  * mark the head page dirty
827  */
828 static int hugetlbfs_set_page_dirty(struct page *page)
829 {
830         struct page *head = compound_head(page);
831 
832         SetPageDirty(head);
833         return 0;
834 }
835 
836 static int hugetlbfs_migrate_page(struct address_space *mapping,
837                                 struct page *newpage, struct page *page,
838                                 enum migrate_mode mode)
839 {
840         int rc;
841 
842         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
843         if (rc != MIGRATEPAGE_SUCCESS)
844                 return rc;
845         migrate_page_copy(newpage, page);
846 
847         return MIGRATEPAGE_SUCCESS;
848 }
849 
850 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
851 {
852         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
853         struct hstate *h = hstate_inode(d_inode(dentry));
854 
855         buf->f_type = HUGETLBFS_MAGIC;
856         buf->f_bsize = huge_page_size(h);
857         if (sbinfo) {
858                 spin_lock(&sbinfo->stat_lock);
859                 /* If no limits set, just report 0 for max/free/used
860                  * blocks, like simple_statfs() */
861                 if (sbinfo->spool) {
862                         long free_pages;
863 
864                         spin_lock(&sbinfo->spool->lock);
865                         buf->f_blocks = sbinfo->spool->max_hpages;
866                         free_pages = sbinfo->spool->max_hpages
867                                 - sbinfo->spool->used_hpages;
868                         buf->f_bavail = buf->f_bfree = free_pages;
869                         spin_unlock(&sbinfo->spool->lock);
870                         buf->f_files = sbinfo->max_inodes;
871                         buf->f_ffree = sbinfo->free_inodes;
872                 }
873                 spin_unlock(&sbinfo->stat_lock);
874         }
875         buf->f_namelen = NAME_MAX;
876         return 0;
877 }
878 
879 static void hugetlbfs_put_super(struct super_block *sb)
880 {
881         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
882 
883         if (sbi) {
884                 sb->s_fs_info = NULL;
885 
886                 if (sbi->spool)
887                         hugepage_put_subpool(sbi->spool);
888 
889                 kfree(sbi);
890         }
891 }
892 
893 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
894 {
895         if (sbinfo->free_inodes >= 0) {
896                 spin_lock(&sbinfo->stat_lock);
897                 if (unlikely(!sbinfo->free_inodes)) {
898                         spin_unlock(&sbinfo->stat_lock);
899                         return 0;
900                 }
901                 sbinfo->free_inodes--;
902                 spin_unlock(&sbinfo->stat_lock);
903         }
904 
905         return 1;
906 }
907 
908 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
909 {
910         if (sbinfo->free_inodes >= 0) {
911                 spin_lock(&sbinfo->stat_lock);
912                 sbinfo->free_inodes++;
913                 spin_unlock(&sbinfo->stat_lock);
914         }
915 }
916 
917 
918 static struct kmem_cache *hugetlbfs_inode_cachep;
919 
920 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
921 {
922         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
923         struct hugetlbfs_inode_info *p;
924 
925         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
926                 return NULL;
927         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
928         if (unlikely(!p)) {
929                 hugetlbfs_inc_free_inodes(sbinfo);
930                 return NULL;
931         }
932         return &p->vfs_inode;
933 }
934 
935 static void hugetlbfs_i_callback(struct rcu_head *head)
936 {
937         struct inode *inode = container_of(head, struct inode, i_rcu);
938         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
939 }
940 
941 static void hugetlbfs_destroy_inode(struct inode *inode)
942 {
943         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
944         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
945         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
946 }
947 
948 static const struct address_space_operations hugetlbfs_aops = {
949         .write_begin    = hugetlbfs_write_begin,
950         .write_end      = hugetlbfs_write_end,
951         .set_page_dirty = hugetlbfs_set_page_dirty,
952         .migratepage    = hugetlbfs_migrate_page,
953 };
954 
955 
956 static void init_once(void *foo)
957 {
958         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
959 
960         inode_init_once(&ei->vfs_inode);
961 }
962 
963 const struct file_operations hugetlbfs_file_operations = {
964         .read_iter              = hugetlbfs_read_iter,
965         .mmap                   = hugetlbfs_file_mmap,
966         .fsync                  = noop_fsync,
967         .get_unmapped_area      = hugetlb_get_unmapped_area,
968         .llseek                 = default_llseek,
969         .fallocate              = hugetlbfs_fallocate,
970 };
971 
972 static const struct inode_operations hugetlbfs_dir_inode_operations = {
973         .create         = hugetlbfs_create,
974         .lookup         = simple_lookup,
975         .link           = simple_link,
976         .unlink         = simple_unlink,
977         .symlink        = hugetlbfs_symlink,
978         .mkdir          = hugetlbfs_mkdir,
979         .rmdir          = simple_rmdir,
980         .mknod          = hugetlbfs_mknod,
981         .rename         = simple_rename,
982         .setattr        = hugetlbfs_setattr,
983 };
984 
985 static const struct inode_operations hugetlbfs_inode_operations = {
986         .setattr        = hugetlbfs_setattr,
987 };
988 
989 static const struct super_operations hugetlbfs_ops = {
990         .alloc_inode    = hugetlbfs_alloc_inode,
991         .destroy_inode  = hugetlbfs_destroy_inode,
992         .evict_inode    = hugetlbfs_evict_inode,
993         .statfs         = hugetlbfs_statfs,
994         .put_super      = hugetlbfs_put_super,
995         .show_options   = generic_show_options,
996 };
997 
998 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };
999 
1000 /*
1001  * Convert size option passed from command line to number of huge pages
1002  * in the pool specified by hstate.  Size option could be in bytes
1003  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1004  */
1005 static long long
1006 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1007                                                                 int val_type)
1008 {
1009         if (val_type == NO_SIZE)
1010                 return -1;
1011 
1012         if (val_type == SIZE_PERCENT) {
1013                 size_opt <<= huge_page_shift(h);
1014                 size_opt *= h->max_huge_pages;
1015                 do_div(size_opt, 100);
1016         }
1017 
1018         size_opt >>= huge_page_shift(h);
1019         return size_opt;
1020 }
1021 
1022 static int
1023 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1024 {
1025         char *p, *rest;
1026         substring_t args[MAX_OPT_ARGS];
1027         int option;
1028         unsigned long long max_size_opt = 0, min_size_opt = 0;
1029         int max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1030 
1031         if (!options)
1032                 return 0;
1033 
1034         while ((p = strsep(&options, ",")) != NULL) {
1035                 int token;
1036                 if (!*p)
1037                         continue;
1038 
1039                 token = match_token(p, tokens, args);
1040                 switch (token) {
1041                 case Opt_uid:
1042                         if (match_int(&args[0], &option))
1043                                 goto bad_val;
1044                         pconfig->uid = make_kuid(current_user_ns(), option);
1045                         if (!uid_valid(pconfig->uid))
1046                                 goto bad_val;
1047                         break;
1048 
1049                 case Opt_gid:
1050                         if (match_int(&args[0], &option))
1051                                 goto bad_val;
1052                         pconfig->gid = make_kgid(current_user_ns(), option);
1053                         if (!gid_valid(pconfig->gid))
1054                                 goto bad_val;
1055                         break;
1056 
1057                 case Opt_mode:
1058                         if (match_octal(&args[0], &option))
1059                                 goto bad_val;
1060                         pconfig->mode = option & 01777U;
1061                         break;
1062 
1063                 case Opt_size: {
1064                         /* memparse() will accept a K/M/G without a digit */
1065                         if (!isdigit(*args[0].from))
1066                                 goto bad_val;
1067                         max_size_opt = memparse(args[0].from, &rest);
1068                         max_val_type = SIZE_STD;
1069                         if (*rest == '%')
1070                                 max_val_type = SIZE_PERCENT;
1071                         break;
1072                 }
1073 
1074                 case Opt_nr_inodes:
1075                         /* memparse() will accept a K/M/G without a digit */
1076                         if (!isdigit(*args[0].from))
1077                                 goto bad_val;
1078                         pconfig->nr_inodes = memparse(args[0].from, &rest);
1079                         break;
1080 
1081                 case Opt_pagesize: {
1082                         unsigned long ps;
1083                         ps = memparse(args[0].from, &rest);
1084                         pconfig->hstate = size_to_hstate(ps);
1085                         if (!pconfig->hstate) {
1086                                 pr_err("Unsupported page size %lu MB\n",
1087                                         ps >> 20);
1088                                 return -EINVAL;
1089                         }
1090                         break;
1091                 }
1092 
1093                 case Opt_min_size: {
1094                         /* memparse() will accept a K/M/G without a digit */
1095                         if (!isdigit(*args[0].from))
1096                                 goto bad_val;
1097                         min_size_opt = memparse(args[0].from, &rest);
1098                         min_val_type = SIZE_STD;
1099                         if (*rest == '%')
1100                                 min_val_type = SIZE_PERCENT;
1101                         break;
1102                 }
1103 
1104                 default:
1105                         pr_err("Bad mount option: \"%s\"\n", p);
1106                         return -EINVAL;
1107                         break;
1108                 }
1109         }
1110 
1111         /*
1112          * Use huge page pool size (in hstate) to convert the size
1113          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1114          */
1115         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1116                                                 max_size_opt, max_val_type);
1117         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1118                                                 min_size_opt, min_val_type);
1119 
1120         /*
1121          * If max_size was specified, then min_size must be smaller
1122          */
1123         if (max_val_type > NO_SIZE &&
1124             pconfig->min_hpages > pconfig->max_hpages) {
1125                 pr_err("minimum size can not be greater than maximum size\n");
1126                 return -EINVAL;
1127         }
1128 
1129         return 0;
1130 
1131 bad_val:
1132         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1133         return -EINVAL;
1134 }
1135 
1136 static int
1137 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1138 {
1139         int ret;
1140         struct hugetlbfs_config config;
1141         struct hugetlbfs_sb_info *sbinfo;
1142 
1143         save_mount_options(sb, data);
1144 
1145         config.max_hpages = -1; /* No limit on size by default */
1146         config.nr_inodes = -1; /* No limit on number of inodes by default */
1147         config.uid = current_fsuid();
1148         config.gid = current_fsgid();
1149         config.mode = 0755;
1150         config.hstate = &default_hstate;
1151         config.min_hpages = -1; /* No default minimum size */
1152         ret = hugetlbfs_parse_options(data, &config);
1153         if (ret)
1154                 return ret;
1155 
1156         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1157         if (!sbinfo)
1158                 return -ENOMEM;
1159         sb->s_fs_info = sbinfo;
1160         sbinfo->hstate = config.hstate;
1161         spin_lock_init(&sbinfo->stat_lock);
1162         sbinfo->max_inodes = config.nr_inodes;
1163         sbinfo->free_inodes = config.nr_inodes;
1164         sbinfo->spool = NULL;
1165         /*
1166          * Allocate and initialize subpool if maximum or minimum size is
1167          * specified.  Any needed reservations (for minimim size) are taken
1168          * taken when the subpool is created.
1169          */
1170         if (config.max_hpages != -1 || config.min_hpages != -1) {
1171                 sbinfo->spool = hugepage_new_subpool(config.hstate,
1172                                                         config.max_hpages,
1173                                                         config.min_hpages);
1174                 if (!sbinfo->spool)
1175                         goto out_free;
1176         }
1177         sb->s_maxbytes = MAX_LFS_FILESIZE;
1178         sb->s_blocksize = huge_page_size(config.hstate);
1179         sb->s_blocksize_bits = huge_page_shift(config.hstate);
1180         sb->s_magic = HUGETLBFS_MAGIC;
1181         sb->s_op = &hugetlbfs_ops;
1182         sb->s_time_gran = 1;
1183         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1184         if (!sb->s_root)
1185                 goto out_free;
1186         return 0;
1187 out_free:
1188         kfree(sbinfo->spool);
1189         kfree(sbinfo);
1190         return -ENOMEM;
1191 }
1192 
1193 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1194         int flags, const char *dev_name, void *data)
1195 {
1196         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1197 }
1198 
1199 static struct file_system_type hugetlbfs_fs_type = {
1200         .name           = "hugetlbfs",
1201         .mount          = hugetlbfs_mount,
1202         .kill_sb        = kill_litter_super,
1203 };
1204 MODULE_ALIAS_FS("hugetlbfs");
1205 
1206 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1207 
1208 static int can_do_hugetlb_shm(void)
1209 {
1210         kgid_t shm_group;
1211         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1212         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1213 }
1214 
1215 static int get_hstate_idx(int page_size_log)
1216 {
1217         struct hstate *h = hstate_sizelog(page_size_log);
1218 
1219         if (!h)
1220                 return -1;
1221         return h - hstates;
1222 }
1223 
1224 static const struct dentry_operations anon_ops = {
1225         .d_dname = simple_dname
1226 };
1227 
1228 /*
1229  * Note that size should be aligned to proper hugepage size in caller side,
1230  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1231  */
1232 struct file *hugetlb_file_setup(const char *name, size_t size,
1233                                 vm_flags_t acctflag, struct user_struct **user,
1234                                 int creat_flags, int page_size_log)
1235 {
1236         struct file *file = ERR_PTR(-ENOMEM);
1237         struct inode *inode;
1238         struct path path;
1239         struct super_block *sb;
1240         struct qstr quick_string;
1241         int hstate_idx;
1242 
1243         hstate_idx = get_hstate_idx(page_size_log);
1244         if (hstate_idx < 0)
1245                 return ERR_PTR(-ENODEV);
1246 
1247         *user = NULL;
1248         if (!hugetlbfs_vfsmount[hstate_idx])
1249                 return ERR_PTR(-ENOENT);
1250 
1251         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1252                 *user = current_user();
1253                 if (user_shm_lock(size, *user)) {
1254                         task_lock(current);
1255                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1256                                 current->comm, current->pid);
1257                         task_unlock(current);
1258                 } else {
1259                         *user = NULL;
1260                         return ERR_PTR(-EPERM);
1261                 }
1262         }
1263 
1264         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1265         quick_string.name = name;
1266         quick_string.len = strlen(quick_string.name);
1267         quick_string.hash = 0;
1268         path.dentry = d_alloc_pseudo(sb, &quick_string);
1269         if (!path.dentry)
1270                 goto out_shm_unlock;
1271 
1272         d_set_d_op(path.dentry, &anon_ops);
1273         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1274         file = ERR_PTR(-ENOSPC);
1275         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1276         if (!inode)
1277                 goto out_dentry;
1278         if (creat_flags == HUGETLB_SHMFS_INODE)
1279                 inode->i_flags |= S_PRIVATE;
1280 
1281         file = ERR_PTR(-ENOMEM);
1282         if (hugetlb_reserve_pages(inode, 0,
1283                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1284                         acctflag))
1285                 goto out_inode;
1286 
1287         d_instantiate(path.dentry, inode);
1288         inode->i_size = size;
1289         clear_nlink(inode);
1290 
1291         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1292                         &hugetlbfs_file_operations);
1293         if (IS_ERR(file))
1294                 goto out_dentry; /* inode is already attached */
1295 
1296         return file;
1297 
1298 out_inode:
1299         iput(inode);
1300 out_dentry:
1301         path_put(&path);
1302 out_shm_unlock:
1303         if (*user) {
1304                 user_shm_unlock(size, *user);
1305                 *user = NULL;
1306         }
1307         return file;
1308 }
1309 
1310 static int __init init_hugetlbfs_fs(void)
1311 {
1312         struct hstate *h;
1313         int error;
1314         int i;
1315 
1316         if (!hugepages_supported()) {
1317                 pr_info("disabling because there are no supported hugepage sizes\n");
1318                 return -ENOTSUPP;
1319         }
1320 
1321         error = -ENOMEM;
1322         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1323                                         sizeof(struct hugetlbfs_inode_info),
1324                                         0, 0, init_once);
1325         if (hugetlbfs_inode_cachep == NULL)
1326                 goto out2;
1327 
1328         error = register_filesystem(&hugetlbfs_fs_type);
1329         if (error)
1330                 goto out;
1331 
1332         i = 0;
1333         for_each_hstate(h) {
1334                 char buf[50];
1335                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1336 
1337                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1338                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1339                                                         buf);
1340 
1341                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1342                         pr_err("Cannot mount internal hugetlbfs for "
1343                                 "page size %uK", ps_kb);
1344                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1345                         hugetlbfs_vfsmount[i] = NULL;
1346                 }
1347                 i++;
1348         }
1349         /* Non default hstates are optional */
1350         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1351                 return 0;
1352 
1353  out:
1354         kmem_cache_destroy(hugetlbfs_inode_cachep);
1355  out2:
1356         return error;
1357 }
1358 
1359 static void __exit exit_hugetlbfs_fs(void)
1360 {
1361         struct hstate *h;
1362         int i;
1363 
1364 
1365         /*
1366          * Make sure all delayed rcu free inodes are flushed before we
1367          * destroy cache.
1368          */
1369         rcu_barrier();
1370         kmem_cache_destroy(hugetlbfs_inode_cachep);
1371         i = 0;
1372         for_each_hstate(h)
1373                 kern_unmount(hugetlbfs_vfsmount[i++]);
1374         unregister_filesystem(&hugetlbfs_fs_type);
1375 }
1376 
1377 module_init(init_hugetlbfs_fs)
1378 module_exit(exit_hugetlbfs_fs)
1379 
1380 MODULE_LICENSE("GPL");
1381 

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