2 * hugetlbpage-backed filesystem. Based on ramfs.
4 * Nadia Yvette Chambers, 2002
6 * Copyright (C) 2002 Linus Torvalds.
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/thread_info.h>
13 #include <asm/current.h>
14 #include <linux/falloc.h>
16 #include <linux/mount.h>
17 #include <linux/file.h>
18 #include <linux/kernel.h>
19 #include <linux/writeback.h>
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <linux/init.h>
23 #include <linux/string.h>
24 #include <linux/capability.h>
25 #include <linux/ctype.h>
26 #include <linux/backing-dev.h>
27 #include <linux/hugetlb.h>
28 #include <linux/pagevec.h>
29 #include <linux/fs_parser.h>
30 #include <linux/mman.h>
31 #include <linux/slab.h>
32 #include <linux/dnotify.h>
33 #include <linux/statfs.h>
34 #include <linux/security.h>
35 #include <linux/magic.h>
36 #include <linux/migrate.h>
37 #include <linux/uio.h>
39 #include <linux/uaccess.h>
40 #include <linux/sched/mm.h>
42 static const struct address_space_operations hugetlbfs_aops;
43 const struct file_operations hugetlbfs_file_operations;
44 static const struct inode_operations hugetlbfs_dir_inode_operations;
45 static const struct inode_operations hugetlbfs_inode_operations;
47 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
49 struct hugetlbfs_fs_context {
50 struct hstate *hstate;
51 unsigned long long max_size_opt;
52 unsigned long long min_size_opt;
56 enum hugetlbfs_size_type max_val_type;
57 enum hugetlbfs_size_type min_val_type;
63 int sysctl_hugetlb_shm_group;
75 static const struct fs_parameter_spec hugetlb_fs_parameters[] = {
76 fsparam_u32 ("gid", Opt_gid),
77 fsparam_string("min_size", Opt_min_size),
78 fsparam_u32oct("mode", Opt_mode),
79 fsparam_string("nr_inodes", Opt_nr_inodes),
80 fsparam_string("pagesize", Opt_pagesize),
81 fsparam_string("size", Opt_size),
82 fsparam_u32 ("uid", Opt_uid),
87 * Mask used when checking the page offset value passed in via system
88 * calls. This value will be converted to a loff_t which is signed.
89 * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
90 * value. The extra bit (- 1 in the shift value) is to take the sign
93 #define PGOFF_LOFFT_MAX \
94 (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1)))
96 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
98 struct inode *inode = file_inode(file);
99 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
102 struct hstate *h = hstate_file(file);
106 * vma address alignment (but not the pgoff alignment) has
107 * already been checked by prepare_hugepage_range. If you add
108 * any error returns here, do so after setting VM_HUGETLB, so
109 * is_vm_hugetlb_page tests below unmap_region go the right
110 * way when do_mmap unwinds (may be important on powerpc
113 vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
114 vma->vm_ops = &hugetlb_vm_ops;
116 ret = seal_check_write(info->seals, vma);
121 * page based offset in vm_pgoff could be sufficiently large to
122 * overflow a loff_t when converted to byte offset. This can
123 * only happen on architectures where sizeof(loff_t) ==
124 * sizeof(unsigned long). So, only check in those instances.
126 if (sizeof(unsigned long) == sizeof(loff_t)) {
127 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
131 /* must be huge page aligned */
132 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
135 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
136 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
137 /* check for overflow */
146 vm_flags = vma->vm_flags;
148 * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
149 * reserving here. Note: only for SHM hugetlbfs file, the inode
150 * flag S_PRIVATE is set.
152 if (inode->i_flags & S_PRIVATE)
153 vm_flags |= VM_NORESERVE;
155 if (!hugetlb_reserve_pages(inode,
156 vma->vm_pgoff >> huge_page_order(h),
157 len >> huge_page_shift(h), vma,
162 if (vma->vm_flags & VM_WRITE && inode->i_size < len)
163 i_size_write(inode, len);
171 * Called under mmap_write_lock(mm).
175 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
176 unsigned long len, unsigned long pgoff, unsigned long flags)
178 struct hstate *h = hstate_file(file);
179 struct vm_unmapped_area_info info;
183 info.low_limit = current->mm->mmap_base;
184 info.high_limit = arch_get_mmap_end(addr, len, flags);
185 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
186 info.align_offset = 0;
187 return vm_unmapped_area(&info);
191 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
192 unsigned long len, unsigned long pgoff, unsigned long flags)
194 struct hstate *h = hstate_file(file);
195 struct vm_unmapped_area_info info;
197 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
199 info.low_limit = PAGE_SIZE;
200 info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
201 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
202 info.align_offset = 0;
203 addr = vm_unmapped_area(&info);
206 * A failed mmap() very likely causes application failure,
207 * so fall back to the bottom-up function here. This scenario
208 * can happen with large stack limits and large mmap()
211 if (unlikely(offset_in_page(addr))) {
212 VM_BUG_ON(addr != -ENOMEM);
214 info.low_limit = current->mm->mmap_base;
215 info.high_limit = arch_get_mmap_end(addr, len, flags);
216 addr = vm_unmapped_area(&info);
223 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
224 unsigned long len, unsigned long pgoff,
227 struct mm_struct *mm = current->mm;
228 struct vm_area_struct *vma;
229 struct hstate *h = hstate_file(file);
230 const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
232 if (len & ~huge_page_mask(h))
237 if (flags & MAP_FIXED) {
238 if (prepare_hugepage_range(file, addr, len))
244 addr = ALIGN(addr, huge_page_size(h));
245 vma = find_vma(mm, addr);
246 if (mmap_end - len >= addr &&
247 (!vma || addr + len <= vm_start_gap(vma)))
252 * Use mm->get_unmapped_area value as a hint to use topdown routine.
253 * If architectures have special needs, they should define their own
254 * version of hugetlb_get_unmapped_area.
256 if (mm->get_unmapped_area == arch_get_unmapped_area_topdown)
257 return hugetlb_get_unmapped_area_topdown(file, addr, len,
259 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
263 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
265 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
266 unsigned long len, unsigned long pgoff,
269 return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
274 * Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset.
275 * Returns the maximum number of bytes one can read without touching the 1st raw
278 * The implementation borrows the iteration logic from copy_page_to_iter*.
280 static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes)
285 /* First subpage to start the loop. */
286 page = nth_page(page, offset / PAGE_SIZE);
289 if (is_raw_hwpoison_page_in_hugepage(page))
292 /* Safe to read n bytes without touching HWPOISON subpage. */
293 n = min(bytes, (size_t)PAGE_SIZE - offset);
299 if (offset == PAGE_SIZE) {
300 page = nth_page(page, 1);
309 * Support for read() - Find the page attached to f_mapping and copy out the
310 * data. This provides functionality similar to filemap_read().
312 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
314 struct file *file = iocb->ki_filp;
315 struct hstate *h = hstate_file(file);
316 struct address_space *mapping = file->f_mapping;
317 struct inode *inode = mapping->host;
318 unsigned long index = iocb->ki_pos >> huge_page_shift(h);
319 unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
320 unsigned long end_index;
324 while (iov_iter_count(to)) {
326 size_t nr, copied, want;
328 /* nr is the maximum number of bytes to copy from this page */
329 nr = huge_page_size(h);
330 isize = i_size_read(inode);
333 end_index = (isize - 1) >> huge_page_shift(h);
334 if (index > end_index)
336 if (index == end_index) {
337 nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
344 folio = filemap_lock_hugetlb_folio(h, mapping, index);
347 * We have a HOLE, zero out the user-buffer for the
348 * length of the hole or request.
350 copied = iov_iter_zero(nr, to);
354 if (!folio_test_hwpoison(folio))
358 * Adjust how many bytes safe to read without
359 * touching the 1st raw HWPOISON subpage after
362 want = adjust_range_hwpoison(&folio->page, offset, nr);
371 * We have the folio, copy it to user space buffer.
373 copied = copy_folio_to_iter(folio, offset, want, to);
378 if (copied != nr && iov_iter_count(to)) {
383 index += offset >> huge_page_shift(h);
384 offset &= ~huge_page_mask(h);
386 iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
390 static int hugetlbfs_write_begin(struct file *file,
391 struct address_space *mapping,
392 loff_t pos, unsigned len,
393 struct page **pagep, void **fsdata)
398 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
399 loff_t pos, unsigned len, unsigned copied,
400 struct page *page, void *fsdata)
406 static void hugetlb_delete_from_page_cache(struct folio *folio)
408 folio_clear_dirty(folio);
409 folio_clear_uptodate(folio);
410 filemap_remove_folio(folio);
414 * Called with i_mmap_rwsem held for inode based vma maps. This makes
415 * sure vma (and vm_mm) will not go away. We also hold the hugetlb fault
416 * mutex for the page in the mapping. So, we can not race with page being
417 * faulted into the vma.
419 static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
420 unsigned long addr, struct page *page)
424 ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma)));
428 pte = huge_ptep_get(ptep);
429 if (huge_pte_none(pte) || !pte_present(pte))
432 if (pte_page(pte) == page)
439 * Can vma_offset_start/vma_offset_end overflow on 32-bit arches?
440 * No, because the interval tree returns us only those vmas
441 * which overlap the truncated area starting at pgoff,
442 * and no vma on a 32-bit arch can span beyond the 4GB.
444 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
446 unsigned long offset = 0;
448 if (vma->vm_pgoff < start)
449 offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
451 return vma->vm_start + offset;
454 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
461 t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start;
462 if (t_end > vma->vm_end)
468 * Called with hugetlb fault mutex held. Therefore, no more mappings to
469 * this folio can be created while executing the routine.
471 static void hugetlb_unmap_file_folio(struct hstate *h,
472 struct address_space *mapping,
473 struct folio *folio, pgoff_t index)
475 struct rb_root_cached *root = &mapping->i_mmap;
476 struct hugetlb_vma_lock *vma_lock;
477 struct page *page = &folio->page;
478 struct vm_area_struct *vma;
479 unsigned long v_start;
483 start = index * pages_per_huge_page(h);
484 end = (index + 1) * pages_per_huge_page(h);
486 i_mmap_lock_write(mapping);
489 vma_interval_tree_foreach(vma, root, start, end - 1) {
490 v_start = vma_offset_start(vma, start);
491 v_end = vma_offset_end(vma, end);
493 if (!hugetlb_vma_maps_page(vma, v_start, page))
496 if (!hugetlb_vma_trylock_write(vma)) {
497 vma_lock = vma->vm_private_data;
499 * If we can not get vma lock, we need to drop
500 * immap_sema and take locks in order. First,
501 * take a ref on the vma_lock structure so that
502 * we can be guaranteed it will not go away when
503 * dropping immap_sema.
505 kref_get(&vma_lock->refs);
509 unmap_hugepage_range(vma, v_start, v_end, NULL,
510 ZAP_FLAG_DROP_MARKER);
511 hugetlb_vma_unlock_write(vma);
514 i_mmap_unlock_write(mapping);
518 * Wait on vma_lock. We know it is still valid as we have
519 * a reference. We must 'open code' vma locking as we do
520 * not know if vma_lock is still attached to vma.
522 down_write(&vma_lock->rw_sema);
523 i_mmap_lock_write(mapping);
528 * If lock is no longer attached to vma, then just
529 * unlock, drop our reference and retry looking for
532 up_write(&vma_lock->rw_sema);
533 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
538 * vma_lock is still attached to vma. Check to see if vma
539 * still maps page and if so, unmap.
541 v_start = vma_offset_start(vma, start);
542 v_end = vma_offset_end(vma, end);
543 if (hugetlb_vma_maps_page(vma, v_start, page))
544 unmap_hugepage_range(vma, v_start, v_end, NULL,
545 ZAP_FLAG_DROP_MARKER);
547 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
548 hugetlb_vma_unlock_write(vma);
555 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
556 zap_flags_t zap_flags)
558 struct vm_area_struct *vma;
561 * end == 0 indicates that the entire range after start should be
562 * unmapped. Note, end is exclusive, whereas the interval tree takes
563 * an inclusive "last".
565 vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
566 unsigned long v_start;
569 if (!hugetlb_vma_trylock_write(vma))
572 v_start = vma_offset_start(vma, start);
573 v_end = vma_offset_end(vma, end);
575 unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
578 * Note that vma lock only exists for shared/non-private
579 * vmas. Therefore, lock is not held when calling
580 * unmap_hugepage_range for private vmas.
582 hugetlb_vma_unlock_write(vma);
587 * Called with hugetlb fault mutex held.
588 * Returns true if page was actually removed, false otherwise.
590 static bool remove_inode_single_folio(struct hstate *h, struct inode *inode,
591 struct address_space *mapping,
592 struct folio *folio, pgoff_t index,
598 * If folio is mapped, it was faulted in after being
599 * unmapped in caller. Unmap (again) while holding
600 * the fault mutex. The mutex will prevent faults
601 * until we finish removing the folio.
603 if (unlikely(folio_mapped(folio)))
604 hugetlb_unmap_file_folio(h, mapping, folio, index);
608 * We must remove the folio from page cache before removing
609 * the region/ reserve map (hugetlb_unreserve_pages). In
610 * rare out of memory conditions, removal of the region/reserve
611 * map could fail. Correspondingly, the subpool and global
612 * reserve usage count can need to be adjusted.
614 VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio);
615 hugetlb_delete_from_page_cache(folio);
618 if (unlikely(hugetlb_unreserve_pages(inode, index,
620 hugetlb_fix_reserve_counts(inode);
628 * remove_inode_hugepages handles two distinct cases: truncation and hole
629 * punch. There are subtle differences in operation for each case.
631 * truncation is indicated by end of range being LLONG_MAX
632 * In this case, we first scan the range and release found pages.
633 * After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
634 * maps and global counts. Page faults can race with truncation.
635 * During faults, hugetlb_no_page() checks i_size before page allocation,
636 * and again after obtaining page table lock. It will 'back out'
637 * allocations in the truncated range.
638 * hole punch is indicated if end is not LLONG_MAX
639 * In the hole punch case we scan the range and release found pages.
640 * Only when releasing a page is the associated region/reserve map
641 * deleted. The region/reserve map for ranges without associated
642 * pages are not modified. Page faults can race with hole punch.
643 * This is indicated if we find a mapped page.
644 * Note: If the passed end of range value is beyond the end of file, but
645 * not LLONG_MAX this routine still performs a hole punch operation.
647 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
650 struct hstate *h = hstate_inode(inode);
651 struct address_space *mapping = &inode->i_data;
652 const pgoff_t end = lend >> PAGE_SHIFT;
653 struct folio_batch fbatch;
656 bool truncate_op = (lend == LLONG_MAX);
658 folio_batch_init(&fbatch);
659 next = lstart >> PAGE_SHIFT;
660 while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
661 for (i = 0; i < folio_batch_count(&fbatch); ++i) {
662 struct folio *folio = fbatch.folios[i];
665 index = folio->index >> huge_page_order(h);
666 hash = hugetlb_fault_mutex_hash(mapping, index);
667 mutex_lock(&hugetlb_fault_mutex_table[hash]);
670 * Remove folio that was part of folio_batch.
672 if (remove_inode_single_folio(h, inode, mapping, folio,
676 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
678 folio_batch_release(&fbatch);
683 (void)hugetlb_unreserve_pages(inode,
684 lstart >> huge_page_shift(h),
688 static void hugetlbfs_evict_inode(struct inode *inode)
690 struct resv_map *resv_map;
692 remove_inode_hugepages(inode, 0, LLONG_MAX);
695 * Get the resv_map from the address space embedded in the inode.
696 * This is the address space which points to any resv_map allocated
697 * at inode creation time. If this is a device special inode,
698 * i_mapping may not point to the original address space.
700 resv_map = (struct resv_map *)(&inode->i_data)->i_private_data;
701 /* Only regular and link inodes have associated reserve maps */
703 resv_map_release(&resv_map->refs);
707 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
710 struct address_space *mapping = inode->i_mapping;
711 struct hstate *h = hstate_inode(inode);
713 BUG_ON(offset & ~huge_page_mask(h));
714 pgoff = offset >> PAGE_SHIFT;
716 i_size_write(inode, offset);
717 i_mmap_lock_write(mapping);
718 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
719 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
720 ZAP_FLAG_DROP_MARKER);
721 i_mmap_unlock_write(mapping);
722 remove_inode_hugepages(inode, offset, LLONG_MAX);
725 static void hugetlbfs_zero_partial_page(struct hstate *h,
726 struct address_space *mapping,
730 pgoff_t idx = start >> huge_page_shift(h);
733 folio = filemap_lock_hugetlb_folio(h, mapping, idx);
737 start = start & ~huge_page_mask(h);
738 end = end & ~huge_page_mask(h);
740 end = huge_page_size(h);
742 folio_zero_segment(folio, (size_t)start, (size_t)end);
748 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
750 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
751 struct address_space *mapping = inode->i_mapping;
752 struct hstate *h = hstate_inode(inode);
753 loff_t hpage_size = huge_page_size(h);
754 loff_t hole_start, hole_end;
757 * hole_start and hole_end indicate the full pages within the hole.
759 hole_start = round_up(offset, hpage_size);
760 hole_end = round_down(offset + len, hpage_size);
764 /* protected by i_rwsem */
765 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
770 i_mmap_lock_write(mapping);
772 /* If range starts before first full page, zero partial page. */
773 if (offset < hole_start)
774 hugetlbfs_zero_partial_page(h, mapping,
775 offset, min(offset + len, hole_start));
777 /* Unmap users of full pages in the hole. */
778 if (hole_end > hole_start) {
779 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
780 hugetlb_vmdelete_list(&mapping->i_mmap,
781 hole_start >> PAGE_SHIFT,
782 hole_end >> PAGE_SHIFT, 0);
785 /* If range extends beyond last full page, zero partial page. */
786 if ((offset + len) > hole_end && (offset + len) > hole_start)
787 hugetlbfs_zero_partial_page(h, mapping,
788 hole_end, offset + len);
790 i_mmap_unlock_write(mapping);
792 /* Remove full pages from the file. */
793 if (hole_end > hole_start)
794 remove_inode_hugepages(inode, hole_start, hole_end);
801 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
804 struct inode *inode = file_inode(file);
805 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
806 struct address_space *mapping = inode->i_mapping;
807 struct hstate *h = hstate_inode(inode);
808 struct vm_area_struct pseudo_vma;
809 struct mm_struct *mm = current->mm;
810 loff_t hpage_size = huge_page_size(h);
811 unsigned long hpage_shift = huge_page_shift(h);
812 pgoff_t start, index, end;
816 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
819 if (mode & FALLOC_FL_PUNCH_HOLE)
820 return hugetlbfs_punch_hole(inode, offset, len);
823 * Default preallocate case.
824 * For this range, start is rounded down and end is rounded up
825 * as well as being converted to page offsets.
827 start = offset >> hpage_shift;
828 end = (offset + len + hpage_size - 1) >> hpage_shift;
832 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
833 error = inode_newsize_ok(inode, offset + len);
837 if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
843 * Initialize a pseudo vma as this is required by the huge page
844 * allocation routines.
846 vma_init(&pseudo_vma, mm);
847 vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
848 pseudo_vma.vm_file = file;
850 for (index = start; index < end; index++) {
852 * This is supposed to be the vaddr where the page is being
853 * faulted in, but we have no vaddr here.
861 * fallocate(2) manpage permits EINTR; we may have been
862 * interrupted because we are using up too much memory.
864 if (signal_pending(current)) {
869 /* addr is the offset within the file (zero based) */
870 addr = index * hpage_size;
872 /* mutex taken here, fault path and hole punch */
873 hash = hugetlb_fault_mutex_hash(mapping, index);
874 mutex_lock(&hugetlb_fault_mutex_table[hash]);
876 /* See if already present in mapping to avoid alloc/free */
877 folio = filemap_get_folio(mapping, index << huge_page_order(h));
878 if (!IS_ERR(folio)) {
880 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
885 * Allocate folio without setting the avoid_reserve argument.
886 * There certainly are no reserves associated with the
887 * pseudo_vma. However, there could be shared mappings with
888 * reserves for the file at the inode level. If we fallocate
889 * folios in these areas, we need to consume the reserves
890 * to keep reservation accounting consistent.
892 folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0);
894 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
895 error = PTR_ERR(folio);
898 clear_huge_page(&folio->page, addr, pages_per_huge_page(h));
899 __folio_mark_uptodate(folio);
900 error = hugetlb_add_to_page_cache(folio, mapping, index);
901 if (unlikely(error)) {
902 restore_reserve_on_error(h, &pseudo_vma, addr, folio);
904 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
908 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
910 folio_set_hugetlb_migratable(folio);
912 * folio_unlock because locked by hugetlb_add_to_page_cache()
913 * folio_put() due to reference from alloc_hugetlb_folio()
919 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
920 i_size_write(inode, offset + len);
921 inode_set_ctime_current(inode);
927 static int hugetlbfs_setattr(struct mnt_idmap *idmap,
928 struct dentry *dentry, struct iattr *attr)
930 struct inode *inode = d_inode(dentry);
931 struct hstate *h = hstate_inode(inode);
933 unsigned int ia_valid = attr->ia_valid;
934 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
936 error = setattr_prepare(idmap, dentry, attr);
940 if (ia_valid & ATTR_SIZE) {
941 loff_t oldsize = inode->i_size;
942 loff_t newsize = attr->ia_size;
944 if (newsize & ~huge_page_mask(h))
946 /* protected by i_rwsem */
947 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
948 (newsize > oldsize && (info->seals & F_SEAL_GROW)))
950 hugetlb_vmtruncate(inode, newsize);
953 setattr_copy(idmap, inode, attr);
954 mark_inode_dirty(inode);
958 static struct inode *hugetlbfs_get_root(struct super_block *sb,
959 struct hugetlbfs_fs_context *ctx)
963 inode = new_inode(sb);
965 inode->i_ino = get_next_ino();
966 inode->i_mode = S_IFDIR | ctx->mode;
967 inode->i_uid = ctx->uid;
968 inode->i_gid = ctx->gid;
969 simple_inode_init_ts(inode);
970 inode->i_op = &hugetlbfs_dir_inode_operations;
971 inode->i_fop = &simple_dir_operations;
972 /* directory inodes start off with i_nlink == 2 (for "." entry) */
974 lockdep_annotate_inode_mutex_key(inode);
980 * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
981 * be taken from reclaim -- unlike regular filesystems. This needs an
982 * annotation because huge_pmd_share() does an allocation under hugetlb's
985 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
987 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
988 struct mnt_idmap *idmap,
990 umode_t mode, dev_t dev)
993 struct resv_map *resv_map = NULL;
996 * Reserve maps are only needed for inodes that can have associated
999 if (S_ISREG(mode) || S_ISLNK(mode)) {
1000 resv_map = resv_map_alloc();
1005 inode = new_inode(sb);
1007 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
1009 inode->i_ino = get_next_ino();
1010 inode_init_owner(idmap, inode, dir, mode);
1011 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
1012 &hugetlbfs_i_mmap_rwsem_key);
1013 inode->i_mapping->a_ops = &hugetlbfs_aops;
1014 simple_inode_init_ts(inode);
1015 inode->i_mapping->i_private_data = resv_map;
1016 info->seals = F_SEAL_SEAL;
1017 switch (mode & S_IFMT) {
1019 init_special_inode(inode, mode, dev);
1022 inode->i_op = &hugetlbfs_inode_operations;
1023 inode->i_fop = &hugetlbfs_file_operations;
1026 inode->i_op = &hugetlbfs_dir_inode_operations;
1027 inode->i_fop = &simple_dir_operations;
1029 /* directory inodes start off with i_nlink == 2 (for "." entry) */
1033 inode->i_op = &page_symlink_inode_operations;
1034 inode_nohighmem(inode);
1037 lockdep_annotate_inode_mutex_key(inode);
1040 kref_put(&resv_map->refs, resv_map_release);
1047 * File creation. Allocate an inode, and we're done..
1049 static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1050 struct dentry *dentry, umode_t mode, dev_t dev)
1052 struct inode *inode;
1054 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, dev);
1057 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1058 d_instantiate(dentry, inode);
1059 dget(dentry);/* Extra count - pin the dentry in core */
1063 static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
1064 struct dentry *dentry, umode_t mode)
1066 int retval = hugetlbfs_mknod(idmap, dir, dentry,
1073 static int hugetlbfs_create(struct mnt_idmap *idmap,
1074 struct inode *dir, struct dentry *dentry,
1075 umode_t mode, bool excl)
1077 return hugetlbfs_mknod(idmap, dir, dentry, mode | S_IFREG, 0);
1080 static int hugetlbfs_tmpfile(struct mnt_idmap *idmap,
1081 struct inode *dir, struct file *file,
1084 struct inode *inode;
1086 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode | S_IFREG, 0);
1089 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1090 d_tmpfile(file, inode);
1091 return finish_open_simple(file, 0);
1094 static int hugetlbfs_symlink(struct mnt_idmap *idmap,
1095 struct inode *dir, struct dentry *dentry,
1096 const char *symname)
1098 const umode_t mode = S_IFLNK|S_IRWXUGO;
1099 struct inode *inode;
1100 int error = -ENOSPC;
1102 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, 0);
1104 int l = strlen(symname)+1;
1105 error = page_symlink(inode, symname, l);
1107 d_instantiate(dentry, inode);
1112 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1117 #ifdef CONFIG_MIGRATION
1118 static int hugetlbfs_migrate_folio(struct address_space *mapping,
1119 struct folio *dst, struct folio *src,
1120 enum migrate_mode mode)
1124 rc = migrate_huge_page_move_mapping(mapping, dst, src);
1125 if (rc != MIGRATEPAGE_SUCCESS)
1128 if (hugetlb_folio_subpool(src)) {
1129 hugetlb_set_folio_subpool(dst,
1130 hugetlb_folio_subpool(src));
1131 hugetlb_set_folio_subpool(src, NULL);
1134 if (mode != MIGRATE_SYNC_NO_COPY)
1135 folio_migrate_copy(dst, src);
1137 folio_migrate_flags(dst, src);
1139 return MIGRATEPAGE_SUCCESS;
1142 #define hugetlbfs_migrate_folio NULL
1145 static int hugetlbfs_error_remove_folio(struct address_space *mapping,
1146 struct folio *folio)
1152 * Display the mount options in /proc/mounts.
1154 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1156 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1157 struct hugepage_subpool *spool = sbinfo->spool;
1158 unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1159 unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1162 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1163 seq_printf(m, ",uid=%u",
1164 from_kuid_munged(&init_user_ns, sbinfo->uid));
1165 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1166 seq_printf(m, ",gid=%u",
1167 from_kgid_munged(&init_user_ns, sbinfo->gid));
1168 if (sbinfo->mode != 0755)
1169 seq_printf(m, ",mode=%o", sbinfo->mode);
1170 if (sbinfo->max_inodes != -1)
1171 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1175 if (hpage_size >= 1024) {
1179 seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1181 if (spool->max_hpages != -1)
1182 seq_printf(m, ",size=%llu",
1183 (unsigned long long)spool->max_hpages << hpage_shift);
1184 if (spool->min_hpages != -1)
1185 seq_printf(m, ",min_size=%llu",
1186 (unsigned long long)spool->min_hpages << hpage_shift);
1191 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1193 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1194 struct hstate *h = hstate_inode(d_inode(dentry));
1195 u64 id = huge_encode_dev(dentry->d_sb->s_dev);
1197 buf->f_fsid = u64_to_fsid(id);
1198 buf->f_type = HUGETLBFS_MAGIC;
1199 buf->f_bsize = huge_page_size(h);
1201 spin_lock(&sbinfo->stat_lock);
1202 /* If no limits set, just report 0 or -1 for max/free/used
1203 * blocks, like simple_statfs() */
1204 if (sbinfo->spool) {
1207 spin_lock_irq(&sbinfo->spool->lock);
1208 buf->f_blocks = sbinfo->spool->max_hpages;
1209 free_pages = sbinfo->spool->max_hpages
1210 - sbinfo->spool->used_hpages;
1211 buf->f_bavail = buf->f_bfree = free_pages;
1212 spin_unlock_irq(&sbinfo->spool->lock);
1213 buf->f_files = sbinfo->max_inodes;
1214 buf->f_ffree = sbinfo->free_inodes;
1216 spin_unlock(&sbinfo->stat_lock);
1218 buf->f_namelen = NAME_MAX;
1222 static void hugetlbfs_put_super(struct super_block *sb)
1224 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1227 sb->s_fs_info = NULL;
1230 hugepage_put_subpool(sbi->spool);
1236 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1238 if (sbinfo->free_inodes >= 0) {
1239 spin_lock(&sbinfo->stat_lock);
1240 if (unlikely(!sbinfo->free_inodes)) {
1241 spin_unlock(&sbinfo->stat_lock);
1244 sbinfo->free_inodes--;
1245 spin_unlock(&sbinfo->stat_lock);
1251 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1253 if (sbinfo->free_inodes >= 0) {
1254 spin_lock(&sbinfo->stat_lock);
1255 sbinfo->free_inodes++;
1256 spin_unlock(&sbinfo->stat_lock);
1261 static struct kmem_cache *hugetlbfs_inode_cachep;
1263 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1265 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1266 struct hugetlbfs_inode_info *p;
1268 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1270 p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1272 hugetlbfs_inc_free_inodes(sbinfo);
1275 return &p->vfs_inode;
1278 static void hugetlbfs_free_inode(struct inode *inode)
1280 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1283 static void hugetlbfs_destroy_inode(struct inode *inode)
1285 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1288 static const struct address_space_operations hugetlbfs_aops = {
1289 .write_begin = hugetlbfs_write_begin,
1290 .write_end = hugetlbfs_write_end,
1291 .dirty_folio = noop_dirty_folio,
1292 .migrate_folio = hugetlbfs_migrate_folio,
1293 .error_remove_folio = hugetlbfs_error_remove_folio,
1297 static void init_once(void *foo)
1299 struct hugetlbfs_inode_info *ei = foo;
1301 inode_init_once(&ei->vfs_inode);
1304 const struct file_operations hugetlbfs_file_operations = {
1305 .read_iter = hugetlbfs_read_iter,
1306 .mmap = hugetlbfs_file_mmap,
1307 .fsync = noop_fsync,
1308 .get_unmapped_area = hugetlb_get_unmapped_area,
1309 .llseek = default_llseek,
1310 .fallocate = hugetlbfs_fallocate,
1313 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1314 .create = hugetlbfs_create,
1315 .lookup = simple_lookup,
1316 .link = simple_link,
1317 .unlink = simple_unlink,
1318 .symlink = hugetlbfs_symlink,
1319 .mkdir = hugetlbfs_mkdir,
1320 .rmdir = simple_rmdir,
1321 .mknod = hugetlbfs_mknod,
1322 .rename = simple_rename,
1323 .setattr = hugetlbfs_setattr,
1324 .tmpfile = hugetlbfs_tmpfile,
1327 static const struct inode_operations hugetlbfs_inode_operations = {
1328 .setattr = hugetlbfs_setattr,
1331 static const struct super_operations hugetlbfs_ops = {
1332 .alloc_inode = hugetlbfs_alloc_inode,
1333 .free_inode = hugetlbfs_free_inode,
1334 .destroy_inode = hugetlbfs_destroy_inode,
1335 .evict_inode = hugetlbfs_evict_inode,
1336 .statfs = hugetlbfs_statfs,
1337 .put_super = hugetlbfs_put_super,
1338 .show_options = hugetlbfs_show_options,
1342 * Convert size option passed from command line to number of huge pages
1343 * in the pool specified by hstate. Size option could be in bytes
1344 * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1347 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1348 enum hugetlbfs_size_type val_type)
1350 if (val_type == NO_SIZE)
1353 if (val_type == SIZE_PERCENT) {
1354 size_opt <<= huge_page_shift(h);
1355 size_opt *= h->max_huge_pages;
1356 do_div(size_opt, 100);
1359 size_opt >>= huge_page_shift(h);
1364 * Parse one mount parameter.
1366 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1368 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1369 struct fs_parse_result result;
1375 opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1381 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1382 if (!uid_valid(ctx->uid))
1387 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1388 if (!gid_valid(ctx->gid))
1393 ctx->mode = result.uint_32 & 01777U;
1397 /* memparse() will accept a K/M/G without a digit */
1398 if (!param->string || !isdigit(param->string[0]))
1400 ctx->max_size_opt = memparse(param->string, &rest);
1401 ctx->max_val_type = SIZE_STD;
1403 ctx->max_val_type = SIZE_PERCENT;
1407 /* memparse() will accept a K/M/G without a digit */
1408 if (!param->string || !isdigit(param->string[0]))
1410 ctx->nr_inodes = memparse(param->string, &rest);
1414 ps = memparse(param->string, &rest);
1415 h = size_to_hstate(ps);
1417 pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
1424 /* memparse() will accept a K/M/G without a digit */
1425 if (!param->string || !isdigit(param->string[0]))
1427 ctx->min_size_opt = memparse(param->string, &rest);
1428 ctx->min_val_type = SIZE_STD;
1430 ctx->min_val_type = SIZE_PERCENT;
1438 return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1439 param->string, param->key);
1443 * Validate the parsed options.
1445 static int hugetlbfs_validate(struct fs_context *fc)
1447 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1450 * Use huge page pool size (in hstate) to convert the size
1451 * options to number of huge pages. If NO_SIZE, -1 is returned.
1453 ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1456 ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1461 * If max_size was specified, then min_size must be smaller
1463 if (ctx->max_val_type > NO_SIZE &&
1464 ctx->min_hpages > ctx->max_hpages) {
1465 pr_err("Minimum size can not be greater than maximum size\n");
1473 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1475 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1476 struct hugetlbfs_sb_info *sbinfo;
1478 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1481 sb->s_fs_info = sbinfo;
1482 spin_lock_init(&sbinfo->stat_lock);
1483 sbinfo->hstate = ctx->hstate;
1484 sbinfo->max_inodes = ctx->nr_inodes;
1485 sbinfo->free_inodes = ctx->nr_inodes;
1486 sbinfo->spool = NULL;
1487 sbinfo->uid = ctx->uid;
1488 sbinfo->gid = ctx->gid;
1489 sbinfo->mode = ctx->mode;
1492 * Allocate and initialize subpool if maximum or minimum size is
1493 * specified. Any needed reservations (for minimum size) are taken
1494 * when the subpool is created.
1496 if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1497 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1503 sb->s_maxbytes = MAX_LFS_FILESIZE;
1504 sb->s_blocksize = huge_page_size(ctx->hstate);
1505 sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1506 sb->s_magic = HUGETLBFS_MAGIC;
1507 sb->s_op = &hugetlbfs_ops;
1508 sb->s_time_gran = 1;
1511 * Due to the special and limited functionality of hugetlbfs, it does
1512 * not work well as a stacking filesystem.
1514 sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1515 sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1520 kfree(sbinfo->spool);
1525 static int hugetlbfs_get_tree(struct fs_context *fc)
1527 int err = hugetlbfs_validate(fc);
1530 return get_tree_nodev(fc, hugetlbfs_fill_super);
1533 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1535 kfree(fc->fs_private);
1538 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1539 .free = hugetlbfs_fs_context_free,
1540 .parse_param = hugetlbfs_parse_param,
1541 .get_tree = hugetlbfs_get_tree,
1544 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1546 struct hugetlbfs_fs_context *ctx;
1548 ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1552 ctx->max_hpages = -1; /* No limit on size by default */
1553 ctx->nr_inodes = -1; /* No limit on number of inodes by default */
1554 ctx->uid = current_fsuid();
1555 ctx->gid = current_fsgid();
1557 ctx->hstate = &default_hstate;
1558 ctx->min_hpages = -1; /* No default minimum size */
1559 ctx->max_val_type = NO_SIZE;
1560 ctx->min_val_type = NO_SIZE;
1561 fc->fs_private = ctx;
1562 fc->ops = &hugetlbfs_fs_context_ops;
1566 static struct file_system_type hugetlbfs_fs_type = {
1567 .name = "hugetlbfs",
1568 .init_fs_context = hugetlbfs_init_fs_context,
1569 .parameters = hugetlb_fs_parameters,
1570 .kill_sb = kill_litter_super,
1571 .fs_flags = FS_ALLOW_IDMAP,
1574 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1576 static int can_do_hugetlb_shm(void)
1579 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1580 return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1583 static int get_hstate_idx(int page_size_log)
1585 struct hstate *h = hstate_sizelog(page_size_log);
1589 return hstate_index(h);
1593 * Note that size should be aligned to proper hugepage size in caller side,
1594 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1596 struct file *hugetlb_file_setup(const char *name, size_t size,
1597 vm_flags_t acctflag, int creat_flags,
1600 struct inode *inode;
1601 struct vfsmount *mnt;
1605 hstate_idx = get_hstate_idx(page_size_log);
1607 return ERR_PTR(-ENODEV);
1609 mnt = hugetlbfs_vfsmount[hstate_idx];
1611 return ERR_PTR(-ENOENT);
1613 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1614 struct ucounts *ucounts = current_ucounts();
1616 if (user_shm_lock(size, ucounts)) {
1617 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1618 current->comm, current->pid);
1619 user_shm_unlock(size, ucounts);
1621 return ERR_PTR(-EPERM);
1624 file = ERR_PTR(-ENOSPC);
1625 /* hugetlbfs_vfsmount[] mounts do not use idmapped mounts. */
1626 inode = hugetlbfs_get_inode(mnt->mnt_sb, &nop_mnt_idmap, NULL,
1627 S_IFREG | S_IRWXUGO, 0);
1630 if (creat_flags == HUGETLB_SHMFS_INODE)
1631 inode->i_flags |= S_PRIVATE;
1633 inode->i_size = size;
1636 if (!hugetlb_reserve_pages(inode, 0,
1637 size >> huge_page_shift(hstate_inode(inode)), NULL,
1639 file = ERR_PTR(-ENOMEM);
1641 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1642 &hugetlbfs_file_operations);
1651 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1653 struct fs_context *fc;
1654 struct vfsmount *mnt;
1656 fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1660 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1666 pr_err("Cannot mount internal hugetlbfs for page size %luK",
1667 huge_page_size(h) / SZ_1K);
1671 static int __init init_hugetlbfs_fs(void)
1673 struct vfsmount *mnt;
1678 if (!hugepages_supported()) {
1679 pr_info("disabling because there are no supported hugepage sizes\n");
1684 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1685 sizeof(struct hugetlbfs_inode_info),
1686 0, SLAB_ACCOUNT, init_once);
1687 if (hugetlbfs_inode_cachep == NULL)
1690 error = register_filesystem(&hugetlbfs_fs_type);
1694 /* default hstate mount is required */
1695 mnt = mount_one_hugetlbfs(&default_hstate);
1697 error = PTR_ERR(mnt);
1700 hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1702 /* other hstates are optional */
1704 for_each_hstate(h) {
1705 if (i == default_hstate_idx) {
1710 mnt = mount_one_hugetlbfs(h);
1712 hugetlbfs_vfsmount[i] = NULL;
1714 hugetlbfs_vfsmount[i] = mnt;
1721 (void)unregister_filesystem(&hugetlbfs_fs_type);
1723 kmem_cache_destroy(hugetlbfs_inode_cachep);
1727 fs_initcall(init_hugetlbfs_fs)