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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  * License: GPL
  8  */
  9 
 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 11 
 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         inode_lock(inode);
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         inode_unlock(inode);
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_SHIFT;
217         offset = offset & ~PAGE_MASK;
218 
219         while (size) {
220                 size_t n;
221                 chunksize = PAGE_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_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                         put_page(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 static void
328 hugetlb_vmdelete_list(struct rb_root *root, pgoff_t start, pgoff_t end)
329 {
330         struct vm_area_struct *vma;
331 
332         /*
333          * end == 0 indicates that the entire range after
334          * start should be unmapped.
335          */
336         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
337                 unsigned long v_offset;
338                 unsigned long v_end;
339 
340                 /*
341                  * Can the expression below overflow on 32-bit arches?
342                  * No, because the interval tree returns us only those vmas
343                  * which overlap the truncated area starting at pgoff,
344                  * and no vma on a 32-bit arch can span beyond the 4GB.
345                  */
346                 if (vma->vm_pgoff < start)
347                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
348                 else
349                         v_offset = 0;
350 
351                 if (!end)
352                         v_end = vma->vm_end;
353                 else {
354                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
355                                                         + vma->vm_start;
356                         if (v_end > vma->vm_end)
357                                 v_end = vma->vm_end;
358                 }
359 
360                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
361                                                                         NULL);
362         }
363 }
364 
365 /*
366  * remove_inode_hugepages handles two distinct cases: truncation and hole
367  * punch.  There are subtle differences in operation for each case.
368  *
369  * truncation is indicated by end of range being LLONG_MAX
370  *      In this case, we first scan the range and release found pages.
371  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
372  *      maps and global counts.  Page faults can not race with truncation
373  *      in this routine.  hugetlb_no_page() prevents page faults in the
374  *      truncated range.  It checks i_size before allocation, and again after
375  *      with the page table lock for the page held.  The same lock must be
376  *      acquired to unmap a page.
377  * hole punch is indicated if end is not LLONG_MAX
378  *      In the hole punch case we scan the range and release found pages.
379  *      Only when releasing a page is the associated region/reserv map
380  *      deleted.  The region/reserv map for ranges without associated
381  *      pages are not modified.  Page faults can race with hole punch.
382  *      This is indicated if we find a mapped page.
383  * Note: If the passed end of range value is beyond the end of file, but
384  * not LLONG_MAX this routine still performs a hole punch operation.
385  */
386 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
387                                    loff_t lend)
388 {
389         struct hstate *h = hstate_inode(inode);
390         struct address_space *mapping = &inode->i_data;
391         const pgoff_t start = lstart >> huge_page_shift(h);
392         const pgoff_t end = lend >> huge_page_shift(h);
393         struct vm_area_struct pseudo_vma;
394         struct pagevec pvec;
395         pgoff_t next;
396         int i, freed = 0;
397         long lookup_nr = PAGEVEC_SIZE;
398         bool truncate_op = (lend == LLONG_MAX);
399 
400         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
401         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
402         pagevec_init(&pvec, 0);
403         next = start;
404         while (next < end) {
405                 /*
406                  * Don't grab more pages than the number left in the range.
407                  */
408                 if (end - next < lookup_nr)
409                         lookup_nr = end - next;
410 
411                 /*
412                  * When no more pages are found, we are done.
413                  */
414                 if (!pagevec_lookup(&pvec, mapping, next, lookup_nr))
415                         break;
416 
417                 for (i = 0; i < pagevec_count(&pvec); ++i) {
418                         struct page *page = pvec.pages[i];
419                         bool rsv_on_error;
420                         u32 hash;
421 
422                         /*
423                          * The page (index) could be beyond end.  This is
424                          * only possible in the punch hole case as end is
425                          * max page offset in the truncate case.
426                          */
427                         next = page->index;
428                         if (next >= end)
429                                 break;
430 
431                         hash = hugetlb_fault_mutex_hash(h, current->mm,
432                                                         &pseudo_vma,
433                                                         mapping, next, 0);
434                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
435 
436                         /*
437                          * If page is mapped, it was faulted in after being
438                          * unmapped in caller.  Unmap (again) now after taking
439                          * the fault mutex.  The mutex will prevent faults
440                          * until we finish removing the page.
441                          *
442                          * This race can only happen in the hole punch case.
443                          * Getting here in a truncate operation is a bug.
444                          */
445                         if (unlikely(page_mapped(page))) {
446                                 BUG_ON(truncate_op);
447 
448                                 i_mmap_lock_write(mapping);
449                                 hugetlb_vmdelete_list(&mapping->i_mmap,
450                                         next * pages_per_huge_page(h),
451                                         (next + 1) * pages_per_huge_page(h));
452                                 i_mmap_unlock_write(mapping);
453                         }
454 
455                         lock_page(page);
456                         /*
457                          * We must free the huge page and remove from page
458                          * cache (remove_huge_page) BEFORE removing the
459                          * region/reserve map (hugetlb_unreserve_pages).  In
460                          * rare out of memory conditions, removal of the
461                          * region/reserve map could fail.  Before free'ing
462                          * the page, note PagePrivate which is used in case
463                          * of error.
464                          */
465                         rsv_on_error = !PagePrivate(page);
466                         remove_huge_page(page);
467                         freed++;
468                         if (!truncate_op) {
469                                 if (unlikely(hugetlb_unreserve_pages(inode,
470                                                         next, next + 1, 1)))
471                                         hugetlb_fix_reserve_counts(inode,
472                                                                 rsv_on_error);
473                         }
474 
475                         unlock_page(page);
476                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
477                 }
478                 ++next;
479                 huge_pagevec_release(&pvec);
480                 cond_resched();
481         }
482 
483         if (truncate_op)
484                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
485 }
486 
487 static void hugetlbfs_evict_inode(struct inode *inode)
488 {
489         struct resv_map *resv_map;
490 
491         remove_inode_hugepages(inode, 0, LLONG_MAX);
492         resv_map = (struct resv_map *)inode->i_mapping->private_data;
493         /* root inode doesn't have the resv_map, so we should check it */
494         if (resv_map)
495                 resv_map_release(&resv_map->refs);
496         clear_inode(inode);
497 }
498 
499 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
500 {
501         pgoff_t pgoff;
502         struct address_space *mapping = inode->i_mapping;
503         struct hstate *h = hstate_inode(inode);
504 
505         BUG_ON(offset & ~huge_page_mask(h));
506         pgoff = offset >> PAGE_SHIFT;
507 
508         i_size_write(inode, offset);
509         i_mmap_lock_write(mapping);
510         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
511                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
512         i_mmap_unlock_write(mapping);
513         remove_inode_hugepages(inode, offset, LLONG_MAX);
514         return 0;
515 }
516 
517 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
518 {
519         struct hstate *h = hstate_inode(inode);
520         loff_t hpage_size = huge_page_size(h);
521         loff_t hole_start, hole_end;
522 
523         /*
524          * For hole punch round up the beginning offset of the hole and
525          * round down the end.
526          */
527         hole_start = round_up(offset, hpage_size);
528         hole_end = round_down(offset + len, hpage_size);
529 
530         if (hole_end > hole_start) {
531                 struct address_space *mapping = inode->i_mapping;
532 
533                 inode_lock(inode);
534                 i_mmap_lock_write(mapping);
535                 if (!RB_EMPTY_ROOT(&mapping->i_mmap))
536                         hugetlb_vmdelete_list(&mapping->i_mmap,
537                                                 hole_start >> PAGE_SHIFT,
538                                                 hole_end  >> PAGE_SHIFT);
539                 i_mmap_unlock_write(mapping);
540                 remove_inode_hugepages(inode, hole_start, hole_end);
541                 inode_unlock(inode);
542         }
543 
544         return 0;
545 }
546 
547 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
548                                 loff_t len)
549 {
550         struct inode *inode = file_inode(file);
551         struct address_space *mapping = inode->i_mapping;
552         struct hstate *h = hstate_inode(inode);
553         struct vm_area_struct pseudo_vma;
554         struct mm_struct *mm = current->mm;
555         loff_t hpage_size = huge_page_size(h);
556         unsigned long hpage_shift = huge_page_shift(h);
557         pgoff_t start, index, end;
558         int error;
559         u32 hash;
560 
561         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
562                 return -EOPNOTSUPP;
563 
564         if (mode & FALLOC_FL_PUNCH_HOLE)
565                 return hugetlbfs_punch_hole(inode, offset, len);
566 
567         /*
568          * Default preallocate case.
569          * For this range, start is rounded down and end is rounded up
570          * as well as being converted to page offsets.
571          */
572         start = offset >> hpage_shift;
573         end = (offset + len + hpage_size - 1) >> hpage_shift;
574 
575         inode_lock(inode);
576 
577         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
578         error = inode_newsize_ok(inode, offset + len);
579         if (error)
580                 goto out;
581 
582         /*
583          * Initialize a pseudo vma as this is required by the huge page
584          * allocation routines.  If NUMA is configured, use page index
585          * as input to create an allocation policy.
586          */
587         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
588         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
589         pseudo_vma.vm_file = file;
590 
591         for (index = start; index < end; index++) {
592                 /*
593                  * This is supposed to be the vaddr where the page is being
594                  * faulted in, but we have no vaddr here.
595                  */
596                 struct page *page;
597                 unsigned long addr;
598                 int avoid_reserve = 0;
599 
600                 cond_resched();
601 
602                 /*
603                  * fallocate(2) manpage permits EINTR; we may have been
604                  * interrupted because we are using up too much memory.
605                  */
606                 if (signal_pending(current)) {
607                         error = -EINTR;
608                         break;
609                 }
610 
611                 /* Set numa allocation policy based on index */
612                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
613 
614                 /* addr is the offset within the file (zero based) */
615                 addr = index * hpage_size;
616 
617                 /* mutex taken here, fault path and hole punch */
618                 hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
619                                                 index, addr);
620                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
621 
622                 /* See if already present in mapping to avoid alloc/free */
623                 page = find_get_page(mapping, index);
624                 if (page) {
625                         put_page(page);
626                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
627                         hugetlb_drop_vma_policy(&pseudo_vma);
628                         continue;
629                 }
630 
631                 /* Allocate page and add to page cache */
632                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
633                 hugetlb_drop_vma_policy(&pseudo_vma);
634                 if (IS_ERR(page)) {
635                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
636                         error = PTR_ERR(page);
637                         goto out;
638                 }
639                 clear_huge_page(page, addr, pages_per_huge_page(h));
640                 __SetPageUptodate(page);
641                 error = huge_add_to_page_cache(page, mapping, index);
642                 if (unlikely(error)) {
643                         put_page(page);
644                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
645                         goto out;
646                 }
647 
648                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
649 
650                 /*
651                  * page_put due to reference from alloc_huge_page()
652                  * unlock_page because locked by add_to_page_cache()
653                  */
654                 put_page(page);
655                 unlock_page(page);
656         }
657 
658         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
659                 i_size_write(inode, offset + len);
660         inode->i_ctime = CURRENT_TIME;
661 out:
662         inode_unlock(inode);
663         return error;
664 }
665 
666 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
667 {
668         struct inode *inode = d_inode(dentry);
669         struct hstate *h = hstate_inode(inode);
670         int error;
671         unsigned int ia_valid = attr->ia_valid;
672 
673         BUG_ON(!inode);
674 
675         error = inode_change_ok(inode, attr);
676         if (error)
677                 return error;
678 
679         if (ia_valid & ATTR_SIZE) {
680                 error = -EINVAL;
681                 if (attr->ia_size & ~huge_page_mask(h))
682                         return -EINVAL;
683                 error = hugetlb_vmtruncate(inode, attr->ia_size);
684                 if (error)
685                         return error;
686         }
687 
688         setattr_copy(inode, attr);
689         mark_inode_dirty(inode);
690         return 0;
691 }
692 
693 static struct inode *hugetlbfs_get_root(struct super_block *sb,
694                                         struct hugetlbfs_config *config)
695 {
696         struct inode *inode;
697 
698         inode = new_inode(sb);
699         if (inode) {
700                 struct hugetlbfs_inode_info *info;
701                 inode->i_ino = get_next_ino();
702                 inode->i_mode = S_IFDIR | config->mode;
703                 inode->i_uid = config->uid;
704                 inode->i_gid = config->gid;
705                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
706                 info = HUGETLBFS_I(inode);
707                 mpol_shared_policy_init(&info->policy, NULL);
708                 inode->i_op = &hugetlbfs_dir_inode_operations;
709                 inode->i_fop = &simple_dir_operations;
710                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
711                 inc_nlink(inode);
712                 lockdep_annotate_inode_mutex_key(inode);
713         }
714         return inode;
715 }
716 
717 /*
718  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
719  * be taken from reclaim -- unlike regular filesystems. This needs an
720  * annotation because huge_pmd_share() does an allocation under hugetlb's
721  * i_mmap_rwsem.
722  */
723 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
724 
725 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
726                                         struct inode *dir,
727                                         umode_t mode, dev_t dev)
728 {
729         struct inode *inode;
730         struct resv_map *resv_map;
731 
732         resv_map = resv_map_alloc();
733         if (!resv_map)
734                 return NULL;
735 
736         inode = new_inode(sb);
737         if (inode) {
738                 struct hugetlbfs_inode_info *info;
739                 inode->i_ino = get_next_ino();
740                 inode_init_owner(inode, dir, mode);
741                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
742                                 &hugetlbfs_i_mmap_rwsem_key);
743                 inode->i_mapping->a_ops = &hugetlbfs_aops;
744                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
745                 inode->i_mapping->private_data = resv_map;
746                 info = HUGETLBFS_I(inode);
747                 /*
748                  * The policy is initialized here even if we are creating a
749                  * private inode because initialization simply creates an
750                  * an empty rb tree and calls rwlock_init(), later when we
751                  * call mpol_free_shared_policy() it will just return because
752                  * the rb tree will still be empty.
753                  */
754                 mpol_shared_policy_init(&info->policy, NULL);
755                 switch (mode & S_IFMT) {
756                 default:
757                         init_special_inode(inode, mode, dev);
758                         break;
759                 case S_IFREG:
760                         inode->i_op = &hugetlbfs_inode_operations;
761                         inode->i_fop = &hugetlbfs_file_operations;
762                         break;
763                 case S_IFDIR:
764                         inode->i_op = &hugetlbfs_dir_inode_operations;
765                         inode->i_fop = &simple_dir_operations;
766 
767                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
768                         inc_nlink(inode);
769                         break;
770                 case S_IFLNK:
771                         inode->i_op = &page_symlink_inode_operations;
772                         inode_nohighmem(inode);
773                         break;
774                 }
775                 lockdep_annotate_inode_mutex_key(inode);
776         } else
777                 kref_put(&resv_map->refs, resv_map_release);
778 
779         return inode;
780 }
781 
782 /*
783  * File creation. Allocate an inode, and we're done..
784  */
785 static int hugetlbfs_mknod(struct inode *dir,
786                         struct dentry *dentry, umode_t mode, dev_t dev)
787 {
788         struct inode *inode;
789         int error = -ENOSPC;
790 
791         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
792         if (inode) {
793                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
794                 d_instantiate(dentry, inode);
795                 dget(dentry);   /* Extra count - pin the dentry in core */
796                 error = 0;
797         }
798         return error;
799 }
800 
801 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
802 {
803         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
804         if (!retval)
805                 inc_nlink(dir);
806         return retval;
807 }
808 
809 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
810 {
811         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
812 }
813 
814 static int hugetlbfs_symlink(struct inode *dir,
815                         struct dentry *dentry, const char *symname)
816 {
817         struct inode *inode;
818         int error = -ENOSPC;
819 
820         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
821         if (inode) {
822                 int l = strlen(symname)+1;
823                 error = page_symlink(inode, symname, l);
824                 if (!error) {
825                         d_instantiate(dentry, inode);
826                         dget(dentry);
827                 } else
828                         iput(inode);
829         }
830         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
831 
832         return error;
833 }
834 
835 /*
836  * mark the head page dirty
837  */
838 static int hugetlbfs_set_page_dirty(struct page *page)
839 {
840         struct page *head = compound_head(page);
841 
842         SetPageDirty(head);
843         return 0;
844 }
845 
846 static int hugetlbfs_migrate_page(struct address_space *mapping,
847                                 struct page *newpage, struct page *page,
848                                 enum migrate_mode mode)
849 {
850         int rc;
851 
852         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
853         if (rc != MIGRATEPAGE_SUCCESS)
854                 return rc;
855         migrate_page_copy(newpage, page);
856 
857         return MIGRATEPAGE_SUCCESS;
858 }
859 
860 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
861 {
862         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
863         struct hstate *h = hstate_inode(d_inode(dentry));
864 
865         buf->f_type = HUGETLBFS_MAGIC;
866         buf->f_bsize = huge_page_size(h);
867         if (sbinfo) {
868                 spin_lock(&sbinfo->stat_lock);
869                 /* If no limits set, just report 0 for max/free/used
870                  * blocks, like simple_statfs() */
871                 if (sbinfo->spool) {
872                         long free_pages;
873 
874                         spin_lock(&sbinfo->spool->lock);
875                         buf->f_blocks = sbinfo->spool->max_hpages;
876                         free_pages = sbinfo->spool->max_hpages
877                                 - sbinfo->spool->used_hpages;
878                         buf->f_bavail = buf->f_bfree = free_pages;
879                         spin_unlock(&sbinfo->spool->lock);
880                         buf->f_files = sbinfo->max_inodes;
881                         buf->f_ffree = sbinfo->free_inodes;
882                 }
883                 spin_unlock(&sbinfo->stat_lock);
884         }
885         buf->f_namelen = NAME_MAX;
886         return 0;
887 }
888 
889 static void hugetlbfs_put_super(struct super_block *sb)
890 {
891         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
892 
893         if (sbi) {
894                 sb->s_fs_info = NULL;
895 
896                 if (sbi->spool)
897                         hugepage_put_subpool(sbi->spool);
898 
899                 kfree(sbi);
900         }
901 }
902 
903 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
904 {
905         if (sbinfo->free_inodes >= 0) {
906                 spin_lock(&sbinfo->stat_lock);
907                 if (unlikely(!sbinfo->free_inodes)) {
908                         spin_unlock(&sbinfo->stat_lock);
909                         return 0;
910                 }
911                 sbinfo->free_inodes--;
912                 spin_unlock(&sbinfo->stat_lock);
913         }
914 
915         return 1;
916 }
917 
918 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
919 {
920         if (sbinfo->free_inodes >= 0) {
921                 spin_lock(&sbinfo->stat_lock);
922                 sbinfo->free_inodes++;
923                 spin_unlock(&sbinfo->stat_lock);
924         }
925 }
926 
927 
928 static struct kmem_cache *hugetlbfs_inode_cachep;
929 
930 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
931 {
932         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
933         struct hugetlbfs_inode_info *p;
934 
935         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
936                 return NULL;
937         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
938         if (unlikely(!p)) {
939                 hugetlbfs_inc_free_inodes(sbinfo);
940                 return NULL;
941         }
942         return &p->vfs_inode;
943 }
944 
945 static void hugetlbfs_i_callback(struct rcu_head *head)
946 {
947         struct inode *inode = container_of(head, struct inode, i_rcu);
948         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
949 }
950 
951 static void hugetlbfs_destroy_inode(struct inode *inode)
952 {
953         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
954         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
955         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
956 }
957 
958 static const struct address_space_operations hugetlbfs_aops = {
959         .write_begin    = hugetlbfs_write_begin,
960         .write_end      = hugetlbfs_write_end,
961         .set_page_dirty = hugetlbfs_set_page_dirty,
962         .migratepage    = hugetlbfs_migrate_page,
963 };
964 
965 
966 static void init_once(void *foo)
967 {
968         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
969 
970         inode_init_once(&ei->vfs_inode);
971 }
972 
973 const struct file_operations hugetlbfs_file_operations = {
974         .read_iter              = hugetlbfs_read_iter,
975         .mmap                   = hugetlbfs_file_mmap,
976         .fsync                  = noop_fsync,
977         .get_unmapped_area      = hugetlb_get_unmapped_area,
978         .llseek                 = default_llseek,
979         .fallocate              = hugetlbfs_fallocate,
980 };
981 
982 static const struct inode_operations hugetlbfs_dir_inode_operations = {
983         .create         = hugetlbfs_create,
984         .lookup         = simple_lookup,
985         .link           = simple_link,
986         .unlink         = simple_unlink,
987         .symlink        = hugetlbfs_symlink,
988         .mkdir          = hugetlbfs_mkdir,
989         .rmdir          = simple_rmdir,
990         .mknod          = hugetlbfs_mknod,
991         .rename         = simple_rename,
992         .setattr        = hugetlbfs_setattr,
993 };
994 
995 static const struct inode_operations hugetlbfs_inode_operations = {
996         .setattr        = hugetlbfs_setattr,
997 };
998 
999 static const struct super_operations hugetlbfs_ops = {
1000         .alloc_inode    = hugetlbfs_alloc_inode,
1001         .destroy_inode  = hugetlbfs_destroy_inode,
1002         .evict_inode    = hugetlbfs_evict_inode,
1003         .statfs         = hugetlbfs_statfs,
1004         .put_super      = hugetlbfs_put_super,
1005         .show_options   = generic_show_options,
1006 };
1007 
1008 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };
1009 
1010 /*
1011  * Convert size option passed from command line to number of huge pages
1012  * in the pool specified by hstate.  Size option could be in bytes
1013  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1014  */
1015 static long long
1016 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1017                                                                 int val_type)
1018 {
1019         if (val_type == NO_SIZE)
1020                 return -1;
1021 
1022         if (val_type == SIZE_PERCENT) {
1023                 size_opt <<= huge_page_shift(h);
1024                 size_opt *= h->max_huge_pages;
1025                 do_div(size_opt, 100);
1026         }
1027 
1028         size_opt >>= huge_page_shift(h);
1029         return size_opt;
1030 }
1031 
1032 static int
1033 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1034 {
1035         char *p, *rest;
1036         substring_t args[MAX_OPT_ARGS];
1037         int option;
1038         unsigned long long max_size_opt = 0, min_size_opt = 0;
1039         int max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1040 
1041         if (!options)
1042                 return 0;
1043 
1044         while ((p = strsep(&options, ",")) != NULL) {
1045                 int token;
1046                 if (!*p)
1047                         continue;
1048 
1049                 token = match_token(p, tokens, args);
1050                 switch (token) {
1051                 case Opt_uid:
1052                         if (match_int(&args[0], &option))
1053                                 goto bad_val;
1054                         pconfig->uid = make_kuid(current_user_ns(), option);
1055                         if (!uid_valid(pconfig->uid))
1056                                 goto bad_val;
1057                         break;
1058 
1059                 case Opt_gid:
1060                         if (match_int(&args[0], &option))
1061                                 goto bad_val;
1062                         pconfig->gid = make_kgid(current_user_ns(), option);
1063                         if (!gid_valid(pconfig->gid))
1064                                 goto bad_val;
1065                         break;
1066 
1067                 case Opt_mode:
1068                         if (match_octal(&args[0], &option))
1069                                 goto bad_val;
1070                         pconfig->mode = option & 01777U;
1071                         break;
1072 
1073                 case Opt_size: {
1074                         /* memparse() will accept a K/M/G without a digit */
1075                         if (!isdigit(*args[0].from))
1076                                 goto bad_val;
1077                         max_size_opt = memparse(args[0].from, &rest);
1078                         max_val_type = SIZE_STD;
1079                         if (*rest == '%')
1080                                 max_val_type = SIZE_PERCENT;
1081                         break;
1082                 }
1083 
1084                 case Opt_nr_inodes:
1085                         /* memparse() will accept a K/M/G without a digit */
1086                         if (!isdigit(*args[0].from))
1087                                 goto bad_val;
1088                         pconfig->nr_inodes = memparse(args[0].from, &rest);
1089                         break;
1090 
1091                 case Opt_pagesize: {
1092                         unsigned long ps;
1093                         ps = memparse(args[0].from, &rest);
1094                         pconfig->hstate = size_to_hstate(ps);
1095                         if (!pconfig->hstate) {
1096                                 pr_err("Unsupported page size %lu MB\n",
1097                                         ps >> 20);
1098                                 return -EINVAL;
1099                         }
1100                         break;
1101                 }
1102 
1103                 case Opt_min_size: {
1104                         /* memparse() will accept a K/M/G without a digit */
1105                         if (!isdigit(*args[0].from))
1106                                 goto bad_val;
1107                         min_size_opt = memparse(args[0].from, &rest);
1108                         min_val_type = SIZE_STD;
1109                         if (*rest == '%')
1110                                 min_val_type = SIZE_PERCENT;
1111                         break;
1112                 }
1113 
1114                 default:
1115                         pr_err("Bad mount option: \"%s\"\n", p);
1116                         return -EINVAL;
1117                         break;
1118                 }
1119         }
1120 
1121         /*
1122          * Use huge page pool size (in hstate) to convert the size
1123          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1124          */
1125         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1126                                                 max_size_opt, max_val_type);
1127         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1128                                                 min_size_opt, min_val_type);
1129 
1130         /*
1131          * If max_size was specified, then min_size must be smaller
1132          */
1133         if (max_val_type > NO_SIZE &&
1134             pconfig->min_hpages > pconfig->max_hpages) {
1135                 pr_err("minimum size can not be greater than maximum size\n");
1136                 return -EINVAL;
1137         }
1138 
1139         return 0;
1140 
1141 bad_val:
1142         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1143         return -EINVAL;
1144 }
1145 
1146 static int
1147 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1148 {
1149         int ret;
1150         struct hugetlbfs_config config;
1151         struct hugetlbfs_sb_info *sbinfo;
1152 
1153         save_mount_options(sb, data);
1154 
1155         config.max_hpages = -1; /* No limit on size by default */
1156         config.nr_inodes = -1; /* No limit on number of inodes by default */
1157         config.uid = current_fsuid();
1158         config.gid = current_fsgid();
1159         config.mode = 0755;
1160         config.hstate = &default_hstate;
1161         config.min_hpages = -1; /* No default minimum size */
1162         ret = hugetlbfs_parse_options(data, &config);
1163         if (ret)
1164                 return ret;
1165 
1166         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1167         if (!sbinfo)
1168                 return -ENOMEM;
1169         sb->s_fs_info = sbinfo;
1170         sbinfo->hstate = config.hstate;
1171         spin_lock_init(&sbinfo->stat_lock);
1172         sbinfo->max_inodes = config.nr_inodes;
1173         sbinfo->free_inodes = config.nr_inodes;
1174         sbinfo->spool = NULL;
1175         /*
1176          * Allocate and initialize subpool if maximum or minimum size is
1177          * specified.  Any needed reservations (for minimim size) are taken
1178          * taken when the subpool is created.
1179          */
1180         if (config.max_hpages != -1 || config.min_hpages != -1) {
1181                 sbinfo->spool = hugepage_new_subpool(config.hstate,
1182                                                         config.max_hpages,
1183                                                         config.min_hpages);
1184                 if (!sbinfo->spool)
1185                         goto out_free;
1186         }
1187         sb->s_maxbytes = MAX_LFS_FILESIZE;
1188         sb->s_blocksize = huge_page_size(config.hstate);
1189         sb->s_blocksize_bits = huge_page_shift(config.hstate);
1190         sb->s_magic = HUGETLBFS_MAGIC;
1191         sb->s_op = &hugetlbfs_ops;
1192         sb->s_time_gran = 1;
1193         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1194         if (!sb->s_root)
1195                 goto out_free;
1196         return 0;
1197 out_free:
1198         kfree(sbinfo->spool);
1199         kfree(sbinfo);
1200         return -ENOMEM;
1201 }
1202 
1203 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1204         int flags, const char *dev_name, void *data)
1205 {
1206         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1207 }
1208 
1209 static struct file_system_type hugetlbfs_fs_type = {
1210         .name           = "hugetlbfs",
1211         .mount          = hugetlbfs_mount,
1212         .kill_sb        = kill_litter_super,
1213 };
1214 
1215 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1216 
1217 static int can_do_hugetlb_shm(void)
1218 {
1219         kgid_t shm_group;
1220         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1221         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1222 }
1223 
1224 static int get_hstate_idx(int page_size_log)
1225 {
1226         struct hstate *h = hstate_sizelog(page_size_log);
1227 
1228         if (!h)
1229                 return -1;
1230         return h - hstates;
1231 }
1232 
1233 static const struct dentry_operations anon_ops = {
1234         .d_dname = simple_dname
1235 };
1236 
1237 /*
1238  * Note that size should be aligned to proper hugepage size in caller side,
1239  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1240  */
1241 struct file *hugetlb_file_setup(const char *name, size_t size,
1242                                 vm_flags_t acctflag, struct user_struct **user,
1243                                 int creat_flags, int page_size_log)
1244 {
1245         struct file *file = ERR_PTR(-ENOMEM);
1246         struct inode *inode;
1247         struct path path;
1248         struct super_block *sb;
1249         struct qstr quick_string;
1250         int hstate_idx;
1251 
1252         hstate_idx = get_hstate_idx(page_size_log);
1253         if (hstate_idx < 0)
1254                 return ERR_PTR(-ENODEV);
1255 
1256         *user = NULL;
1257         if (!hugetlbfs_vfsmount[hstate_idx])
1258                 return ERR_PTR(-ENOENT);
1259 
1260         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1261                 *user = current_user();
1262                 if (user_shm_lock(size, *user)) {
1263                         task_lock(current);
1264                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1265                                 current->comm, current->pid);
1266                         task_unlock(current);
1267                 } else {
1268                         *user = NULL;
1269                         return ERR_PTR(-EPERM);
1270                 }
1271         }
1272 
1273         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1274         quick_string.name = name;
1275         quick_string.len = strlen(quick_string.name);
1276         quick_string.hash = 0;
1277         path.dentry = d_alloc_pseudo(sb, &quick_string);
1278         if (!path.dentry)
1279                 goto out_shm_unlock;
1280 
1281         d_set_d_op(path.dentry, &anon_ops);
1282         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1283         file = ERR_PTR(-ENOSPC);
1284         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1285         if (!inode)
1286                 goto out_dentry;
1287         if (creat_flags == HUGETLB_SHMFS_INODE)
1288                 inode->i_flags |= S_PRIVATE;
1289 
1290         file = ERR_PTR(-ENOMEM);
1291         if (hugetlb_reserve_pages(inode, 0,
1292                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1293                         acctflag))
1294                 goto out_inode;
1295 
1296         d_instantiate(path.dentry, inode);
1297         inode->i_size = size;
1298         clear_nlink(inode);
1299 
1300         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1301                         &hugetlbfs_file_operations);
1302         if (IS_ERR(file))
1303                 goto out_dentry; /* inode is already attached */
1304 
1305         return file;
1306 
1307 out_inode:
1308         iput(inode);
1309 out_dentry:
1310         path_put(&path);
1311 out_shm_unlock:
1312         if (*user) {
1313                 user_shm_unlock(size, *user);
1314                 *user = NULL;
1315         }
1316         return file;
1317 }
1318 
1319 static int __init init_hugetlbfs_fs(void)
1320 {
1321         struct hstate *h;
1322         int error;
1323         int i;
1324 
1325         if (!hugepages_supported()) {
1326                 pr_info("disabling because there are no supported hugepage sizes\n");
1327                 return -ENOTSUPP;
1328         }
1329 
1330         error = -ENOMEM;
1331         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1332                                         sizeof(struct hugetlbfs_inode_info),
1333                                         0, SLAB_ACCOUNT, init_once);
1334         if (hugetlbfs_inode_cachep == NULL)
1335                 goto out2;
1336 
1337         error = register_filesystem(&hugetlbfs_fs_type);
1338         if (error)
1339                 goto out;
1340 
1341         i = 0;
1342         for_each_hstate(h) {
1343                 char buf[50];
1344                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1345 
1346                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1347                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1348                                                         buf);
1349 
1350                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1351                         pr_err("Cannot mount internal hugetlbfs for "
1352                                 "page size %uK", ps_kb);
1353                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1354                         hugetlbfs_vfsmount[i] = NULL;
1355                 }
1356                 i++;
1357         }
1358         /* Non default hstates are optional */
1359         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1360                 return 0;
1361 
1362  out:
1363         kmem_cache_destroy(hugetlbfs_inode_cachep);
1364  out2:
1365         return error;
1366 }
1367 fs_initcall(init_hugetlbfs_fs)
1368 

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