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[PATCH] mm: update comments to pte lock
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / hugetlbfs / inode.c
CommitLineData
1da177e4
LT		 1/*
2 * hugetlbpage-backed filesystem. Based on ramfs.
3 *
4 * William Irwin, 2002
5 *
6 * Copyright (C) 2002 Linus Torvalds.
7 */
8
9#include <linux/module.h>
10#include <linux/thread_info.h>
11#include <asm/current.h>
12#include <linux/sched.h> /* remove ASAP */
13#include <linux/fs.h>
14#include <linux/mount.h>
15#include <linux/file.h>
16#include <linux/writeback.h>
17#include <linux/pagemap.h>
18#include <linux/highmem.h>
19#include <linux/init.h>
20#include <linux/string.h>
21#include <linux/backing-dev.h>
22#include <linux/hugetlb.h>
23#include <linux/pagevec.h>
24#include <linux/quotaops.h>
25#include <linux/slab.h>
26#include <linux/dnotify.h>
27#include <linux/statfs.h>
28#include <linux/security.h>
29
30#include <asm/uaccess.h>
31
32/* some random number */
33#define HUGETLBFS_MAGIC 0x958458f6
34
35static struct super_operations hugetlbfs_ops;
36static struct address_space_operations hugetlbfs_aops;
37struct file_operations hugetlbfs_file_operations;
38static struct inode_operations hugetlbfs_dir_inode_operations;
39static struct inode_operations hugetlbfs_inode_operations;
40
41static struct backing_dev_info hugetlbfs_backing_dev_info = {
42 .ra_pages = 0, /* No readahead */
43 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
44};
45
46int sysctl_hugetlb_shm_group;
47
48static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
49{
50 struct inode *inode = file->f_dentry->d_inode;
51 struct address_space *mapping = inode->i_mapping;
52 loff_t len, vma_len;
53 int ret;
54
55 if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE)
56 return -EINVAL;
57
58 if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
59 return -EINVAL;
60
61 if (vma->vm_start & ~HPAGE_MASK)
62 return -EINVAL;
63
64 if (vma->vm_end & ~HPAGE_MASK)
65 return -EINVAL;
66
67 if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
68 return -EINVAL;
69
70 vma_len = (loff_t)(vma->vm_end - vma->vm_start);
71
72 down(&inode->i_sem);
73 file_accessed(file);
74 vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
75 vma->vm_ops = &hugetlb_vm_ops;
76
77 ret = -ENOMEM;
78 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
79 if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
80 goto out;
81
82 ret = hugetlb_prefault(mapping, vma);
83 if (ret)
84 goto out;
85
86 if (inode->i_size < len)
87 inode->i_size = len;
88out:
89 up(&inode->i_sem);
90
91 return ret;
92}
93
94/*
508034a3 95 * Called under down_write(mmap_sem).
1da177e4
LT		 96 */
97
98#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
99unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
100 unsigned long len, unsigned long pgoff, unsigned long flags);
101#else
102static unsigned long
103hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
104 unsigned long len, unsigned long pgoff, unsigned long flags)
105{
106 struct mm_struct *mm = current->mm;
107 struct vm_area_struct *vma;
108 unsigned long start_addr;
109
110 if (len & ~HPAGE_MASK)
111 return -EINVAL;
112 if (len > TASK_SIZE)
113 return -ENOMEM;
114
115 if (addr) {
116 addr = ALIGN(addr, HPAGE_SIZE);
117 vma = find_vma(mm, addr);
118 if (TASK_SIZE - len >= addr &&
119 (!vma || addr + len <= vma->vm_start))
120 return addr;
121 }
122
123 start_addr = mm->free_area_cache;
124
1363c3cd
WW		 125 if (len <= mm->cached_hole_size)
126 start_addr = TASK_UNMAPPED_BASE;
127
1da177e4
LT		 128full_search:
129 addr = ALIGN(start_addr, HPAGE_SIZE);
130
131 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
132 /* At this point: (!vma || addr < vma->vm_end). */
133 if (TASK_SIZE - len < addr) {
134 /*
135 * Start a new search - just in case we missed
136 * some holes.
137 */
138 if (start_addr != TASK_UNMAPPED_BASE) {
139 start_addr = TASK_UNMAPPED_BASE;
140 goto full_search;
141 }
142 return -ENOMEM;
143 }
144
145 if (!vma || addr + len <= vma->vm_start)
146 return addr;
147 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
148 }
149}
150#endif
151
152/*
153 * Read a page. Again trivial. If it didn't already exist
154 * in the page cache, it is zero-filled.
155 */
156static int hugetlbfs_readpage(struct file *file, struct page * page)
157{
158 unlock_page(page);
159 return -EINVAL;
160}
161
162static int hugetlbfs_prepare_write(struct file *file,
163 struct page *page, unsigned offset, unsigned to)
164{
165 return -EINVAL;
166}
167
168static int hugetlbfs_commit_write(struct file *file,
169 struct page *page, unsigned offset, unsigned to)
170{
171 return -EINVAL;
172}
173
174static void huge_pagevec_release(struct pagevec *pvec)
175{
176 int i;
177
178 for (i = 0; i < pagevec_count(pvec); ++i)
179 put_page(pvec->pages[i]);
180
181 pagevec_reinit(pvec);
182}
183
184static void truncate_huge_page(struct page *page)
185{
186 clear_page_dirty(page);
187 ClearPageUptodate(page);
188 remove_from_page_cache(page);
189 put_page(page);
190}
191
192static void truncate_hugepages(struct address_space *mapping, loff_t lstart)
193{
194 const pgoff_t start = lstart >> HPAGE_SHIFT;
195 struct pagevec pvec;
196 pgoff_t next;
197 int i;
198
199 pagevec_init(&pvec, 0);
200 next = start;
201 while (1) {
202 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
203 if (next == start)
204 break;
205 next = start;
206 continue;
207 }
208
209 for (i = 0; i < pagevec_count(&pvec); ++i) {
210 struct page *page = pvec.pages[i];
211
212 lock_page(page);
213 if (page->index > next)
214 next = page->index;
215 ++next;
216 truncate_huge_page(page);
217 unlock_page(page);
218 hugetlb_put_quota(mapping);
219 }
220 huge_pagevec_release(&pvec);
221 }
222 BUG_ON(!lstart && mapping->nrpages);
223}
224
225static void hugetlbfs_delete_inode(struct inode *inode)
226{
227 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(inode->i_sb);
228
229 hlist_del_init(&inode->i_hash);
230 list_del_init(&inode->i_list);
231 list_del_init(&inode->i_sb_list);
232 inode->i_state |= I_FREEING;
233 inodes_stat.nr_inodes--;
234 spin_unlock(&inode_lock);
235
236 if (inode->i_data.nrpages)
237 truncate_hugepages(&inode->i_data, 0);
238
239 security_inode_delete(inode);
240
241 if (sbinfo->free_inodes >= 0) {
242 spin_lock(&sbinfo->stat_lock);
243 sbinfo->free_inodes++;
244 spin_unlock(&sbinfo->stat_lock);
245 }
246
247 clear_inode(inode);
248 destroy_inode(inode);
249}
250
251static void hugetlbfs_forget_inode(struct inode *inode)
252{
253 struct super_block *super_block = inode->i_sb;
254 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(super_block);
255
256 if (hlist_unhashed(&inode->i_hash))
257 goto out_truncate;
258
259 if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
260 list_del(&inode->i_list);
261 list_add(&inode->i_list, &inode_unused);
262 }
263 inodes_stat.nr_unused++;
264 if (!super_block || (super_block->s_flags & MS_ACTIVE)) {
265 spin_unlock(&inode_lock);
266 return;
267 }
268
269 /* write_inode_now() ? */
270 inodes_stat.nr_unused--;
271 hlist_del_init(&inode->i_hash);
272out_truncate:
273 list_del_init(&inode->i_list);
274 list_del_init(&inode->i_sb_list);
275 inode->i_state |= I_FREEING;
276 inodes_stat.nr_inodes--;
277 spin_unlock(&inode_lock);
278 if (inode->i_data.nrpages)
279 truncate_hugepages(&inode->i_data, 0);
280
281 if (sbinfo->free_inodes >= 0) {
282 spin_lock(&sbinfo->stat_lock);
283 sbinfo->free_inodes++;
284 spin_unlock(&sbinfo->stat_lock);
285 }
286
287 clear_inode(inode);
288 destroy_inode(inode);
289}
290
291static void hugetlbfs_drop_inode(struct inode *inode)
292{
293 if (!inode->i_nlink)
294 hugetlbfs_delete_inode(inode);
295 else
296 hugetlbfs_forget_inode(inode);
297}
298
299/*
300 * h_pgoff is in HPAGE_SIZE units.
301 * vma->vm_pgoff is in PAGE_SIZE units.
302 */
303static inline void
304hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
305{
306 struct vm_area_struct *vma;
307 struct prio_tree_iter iter;
308
309 vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
310 unsigned long h_vm_pgoff;
1da177e4
LT		 311 unsigned long v_offset;
312
313 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
314 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
315 /*
316 * Is this VMA fully outside the truncation point?
317 */
318 if (h_vm_pgoff >= h_pgoff)
319 v_offset = 0;
320
508034a3
HD		 321 unmap_hugepage_range(vma,
322 vma->vm_start + v_offset, vma->vm_end);
1da177e4
LT		 323 }
324}
325
326/*
327 * Expanding truncates are not allowed.
328 */
329static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
330{
331 unsigned long pgoff;
332 struct address_space *mapping = inode->i_mapping;
333
334 if (offset > inode->i_size)
335 return -EINVAL;
336
337 BUG_ON(offset & ~HPAGE_MASK);
338 pgoff = offset >> HPAGE_SHIFT;
339
340 inode->i_size = offset;
341 spin_lock(&mapping->i_mmap_lock);
342 if (!prio_tree_empty(&mapping->i_mmap))
343 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
344 spin_unlock(&mapping->i_mmap_lock);
345 truncate_hugepages(mapping, offset);
346 return 0;
347}
348
349static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
350{
351 struct inode *inode = dentry->d_inode;
352 int error;
353 unsigned int ia_valid = attr->ia_valid;
354
355 BUG_ON(!inode);
356
357 error = inode_change_ok(inode, attr);
358 if (error)
359 goto out;
360
361 if (ia_valid & ATTR_SIZE) {
362 error = -EINVAL;
363 if (!(attr->ia_size & ~HPAGE_MASK))
364 error = hugetlb_vmtruncate(inode, attr->ia_size);
365 if (error)
366 goto out;
367 attr->ia_valid &= ~ATTR_SIZE;
368 }
369 error = inode_setattr(inode, attr);
370out:
371 return error;
372}
373
374static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
375 gid_t gid, int mode, dev_t dev)
376{
377 struct inode *inode;
378 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
379
380 if (sbinfo->free_inodes >= 0) {
381 spin_lock(&sbinfo->stat_lock);
382 if (!sbinfo->free_inodes) {
383 spin_unlock(&sbinfo->stat_lock);
384 return NULL;
385 }
386 sbinfo->free_inodes--;
387 spin_unlock(&sbinfo->stat_lock);
388 }
389
390 inode = new_inode(sb);
391 if (inode) {
392 struct hugetlbfs_inode_info *info;
393 inode->i_mode = mode;
394 inode->i_uid = uid;
395 inode->i_gid = gid;
396 inode->i_blksize = HPAGE_SIZE;
397 inode->i_blocks = 0;
398 inode->i_mapping->a_ops = &hugetlbfs_aops;
399 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
400 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
401 info = HUGETLBFS_I(inode);
402 mpol_shared_policy_init(&info->policy);
403 switch (mode & S_IFMT) {
404 default:
405 init_special_inode(inode, mode, dev);
406 break;
407 case S_IFREG:
408 inode->i_op = &hugetlbfs_inode_operations;
409 inode->i_fop = &hugetlbfs_file_operations;
410 break;
411 case S_IFDIR:
412 inode->i_op = &hugetlbfs_dir_inode_operations;
413 inode->i_fop = &simple_dir_operations;
414
415 /* directory inodes start off with i_nlink == 2 (for "." entry) */
416 inode->i_nlink++;
417 break;
418 case S_IFLNK:
419 inode->i_op = &page_symlink_inode_operations;
420 break;
421 }
422 }
423 return inode;
424}
425
426/*
427 * File creation. Allocate an inode, and we're done..
428 */
429static int hugetlbfs_mknod(struct inode *dir,
430 struct dentry *dentry, int mode, dev_t dev)
431{
432 struct inode *inode;
433 int error = -ENOSPC;
434 gid_t gid;
435
436 if (dir->i_mode & S_ISGID) {
437 gid = dir->i_gid;
438 if (S_ISDIR(mode))
439 mode |= S_ISGID;
440 } else {
441 gid = current->fsgid;
442 }
443 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
444 if (inode) {
445 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
446 d_instantiate(dentry, inode);
447 dget(dentry); /* Extra count - pin the dentry in core */
448 error = 0;
449 }
450 return error;
451}
452
453static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
454{
455 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
456 if (!retval)
457 dir->i_nlink++;
458 return retval;
459}
460
461static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
462{
463 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
464}
465
466static int hugetlbfs_symlink(struct inode *dir,
467 struct dentry *dentry, const char *symname)
468{
469 struct inode *inode;
470 int error = -ENOSPC;
471 gid_t gid;
472
473 if (dir->i_mode & S_ISGID)
474 gid = dir->i_gid;
475 else
476 gid = current->fsgid;
477
478 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
479 gid, S_IFLNK|S_IRWXUGO, 0);
480 if (inode) {
481 int l = strlen(symname)+1;
482 error = page_symlink(inode, symname, l);
483 if (!error) {
484 d_instantiate(dentry, inode);
485 dget(dentry);
486 } else
487 iput(inode);
488 }
489 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
490
491 return error;
492}
493
494/*
495 * For direct-IO reads into hugetlb pages
496 */
497static int hugetlbfs_set_page_dirty(struct page *page)
498{
499 return 0;
500}
501
502static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
503{
504 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
505
506 buf->f_type = HUGETLBFS_MAGIC;
507 buf->f_bsize = HPAGE_SIZE;
508 if (sbinfo) {
509 spin_lock(&sbinfo->stat_lock);
510 buf->f_blocks = sbinfo->max_blocks;
511 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
512 buf->f_files = sbinfo->max_inodes;
513 buf->f_ffree = sbinfo->free_inodes;
514 spin_unlock(&sbinfo->stat_lock);
515 }
516 buf->f_namelen = NAME_MAX;
517 return 0;
518}
519
520static void hugetlbfs_put_super(struct super_block *sb)
521{
522 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
523
524 if (sbi) {
525 sb->s_fs_info = NULL;
526 kfree(sbi);
527 }
528}
529
530static kmem_cache_t *hugetlbfs_inode_cachep;
531
532static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
533{
534 struct hugetlbfs_inode_info *p;
535
536 p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
537 if (!p)
538 return NULL;
539 return &p->vfs_inode;
540}
541
542static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
543{
544 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
545
546 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
547 SLAB_CTOR_CONSTRUCTOR)
548 inode_init_once(&ei->vfs_inode);
549}
550
551static void hugetlbfs_destroy_inode(struct inode *inode)
552{
553 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
554 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
555}
556
557static struct address_space_operations hugetlbfs_aops = {
558 .readpage = hugetlbfs_readpage,
559 .prepare_write = hugetlbfs_prepare_write,
560 .commit_write = hugetlbfs_commit_write,
561 .set_page_dirty = hugetlbfs_set_page_dirty,
562};
563
564struct file_operations hugetlbfs_file_operations = {
565 .mmap = hugetlbfs_file_mmap,
566 .fsync = simple_sync_file,
567 .get_unmapped_area = hugetlb_get_unmapped_area,
568};
569
570static struct inode_operations hugetlbfs_dir_inode_operations = {
571 .create = hugetlbfs_create,
572 .lookup = simple_lookup,
573 .link = simple_link,
574 .unlink = simple_unlink,
575 .symlink = hugetlbfs_symlink,
576 .mkdir = hugetlbfs_mkdir,
577 .rmdir = simple_rmdir,
578 .mknod = hugetlbfs_mknod,
579 .rename = simple_rename,
580 .setattr = hugetlbfs_setattr,
581};
582
583static struct inode_operations hugetlbfs_inode_operations = {
584 .setattr = hugetlbfs_setattr,
585};
586
587static struct super_operations hugetlbfs_ops = {
588 .alloc_inode = hugetlbfs_alloc_inode,
589 .destroy_inode = hugetlbfs_destroy_inode,
590 .statfs = hugetlbfs_statfs,
591 .drop_inode = hugetlbfs_drop_inode,
592 .put_super = hugetlbfs_put_super,
593};
594
595static int
596hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
597{
598 char *opt, *value, *rest;
599
600 if (!options)
601 return 0;
602 while ((opt = strsep(&options, ",")) != NULL) {
603 if (!*opt)
604 continue;
605
606 value = strchr(opt, '=');
607 if (!value || !*value)
608 return -EINVAL;
609 else
610 *value++ = '\0';
611
612 if (!strcmp(opt, "uid"))
613 pconfig->uid = simple_strtoul(value, &value, 0);
614 else if (!strcmp(opt, "gid"))
615 pconfig->gid = simple_strtoul(value, &value, 0);
616 else if (!strcmp(opt, "mode"))
617 pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
618 else if (!strcmp(opt, "size")) {
619 unsigned long long size = memparse(value, &rest);
620 if (*rest == '%') {
621 size <<= HPAGE_SHIFT;
622 size *= max_huge_pages;
623 do_div(size, 100);
624 rest++;
625 }
626 size &= HPAGE_MASK;
627 pconfig->nr_blocks = (size >> HPAGE_SHIFT);
628 value = rest;
629 } else if (!strcmp(opt,"nr_inodes")) {
630 pconfig->nr_inodes = memparse(value, &rest);
631 value = rest;
632 } else
633 return -EINVAL;
634
635 if (*value)
636 return -EINVAL;
637 }
638 return 0;
639}
640
641static int
642hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
643{
644 struct inode * inode;
645 struct dentry * root;
646 int ret;
647 struct hugetlbfs_config config;
648 struct hugetlbfs_sb_info *sbinfo;
649
650 config.nr_blocks = -1; /* No limit on size by default */
651 config.nr_inodes = -1; /* No limit on number of inodes by default */
652 config.uid = current->fsuid;
653 config.gid = current->fsgid;
654 config.mode = 0755;
655 ret = hugetlbfs_parse_options(data, &config);
656
657 if (ret)
658 return ret;
659
660 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
661 if (!sbinfo)
662 return -ENOMEM;
663 sb->s_fs_info = sbinfo;
664 spin_lock_init(&sbinfo->stat_lock);
665 sbinfo->max_blocks = config.nr_blocks;
666 sbinfo->free_blocks = config.nr_blocks;
667 sbinfo->max_inodes = config.nr_inodes;
668 sbinfo->free_inodes = config.nr_inodes;
669 sb->s_maxbytes = MAX_LFS_FILESIZE;
670 sb->s_blocksize = HPAGE_SIZE;
671 sb->s_blocksize_bits = HPAGE_SHIFT;
672 sb->s_magic = HUGETLBFS_MAGIC;
673 sb->s_op = &hugetlbfs_ops;
674 sb->s_time_gran = 1;
675 inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
676 S_IFDIR | config.mode, 0);
677 if (!inode)
678 goto out_free;
679
680 root = d_alloc_root(inode);
681 if (!root) {
682 iput(inode);
683 goto out_free;
684 }
685 sb->s_root = root;
686 return 0;
687out_free:
688 kfree(sbinfo);
689 return -ENOMEM;
690}
691
692int hugetlb_get_quota(struct address_space *mapping)
693{
694 int ret = 0;
695 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
696
697 if (sbinfo->free_blocks > -1) {
698 spin_lock(&sbinfo->stat_lock);
699 if (sbinfo->free_blocks > 0)
700 sbinfo->free_blocks--;
701 else
702 ret = -ENOMEM;
703 spin_unlock(&sbinfo->stat_lock);
704 }
705
706 return ret;
707}
708
709void hugetlb_put_quota(struct address_space *mapping)
710{
711 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
712
713 if (sbinfo->free_blocks > -1) {
714 spin_lock(&sbinfo->stat_lock);
715 sbinfo->free_blocks++;
716 spin_unlock(&sbinfo->stat_lock);
717 }
718}
719
720static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
721 int flags, const char *dev_name, void *data)
722{
723 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
724}
725
726static struct file_system_type hugetlbfs_fs_type = {
727 .name = "hugetlbfs",
728 .get_sb = hugetlbfs_get_sb,
729 .kill_sb = kill_litter_super,
730};
731
732static struct vfsmount *hugetlbfs_vfsmount;
733
734/*
735 * Return the next identifier for a shm file
736 */
737static unsigned long hugetlbfs_counter(void)
738{
739 static DEFINE_SPINLOCK(lock);
740 static unsigned long counter;
741 unsigned long ret;
742
743 spin_lock(&lock);
744 ret = ++counter;
745 spin_unlock(&lock);
746 return ret;
747}
748
749static int can_do_hugetlb_shm(void)
750{
751 return likely(capable(CAP_IPC_LOCK) ||
752 in_group_p(sysctl_hugetlb_shm_group) ||
753 can_do_mlock());
754}
755
756struct file *hugetlb_zero_setup(size_t size)
757{
758 int error = -ENOMEM;
759 struct file *file;
760 struct inode *inode;
761 struct dentry *dentry, *root;
762 struct qstr quick_string;
763 char buf[16];
764
765 if (!can_do_hugetlb_shm())
766 return ERR_PTR(-EPERM);
767
768 if (!is_hugepage_mem_enough(size))
769 return ERR_PTR(-ENOMEM);
770
771 if (!user_shm_lock(size, current->user))
772 return ERR_PTR(-ENOMEM);
773
774 root = hugetlbfs_vfsmount->mnt_root;
775 snprintf(buf, 16, "%lu", hugetlbfs_counter());
776 quick_string.name = buf;
777 quick_string.len = strlen(quick_string.name);
778 quick_string.hash = 0;
779 dentry = d_alloc(root, &quick_string);
780 if (!dentry)
781 goto out_shm_unlock;
782
783 error = -ENFILE;
784 file = get_empty_filp();
785 if (!file)
786 goto out_dentry;
787
788 error = -ENOSPC;
789 inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
790 current->fsgid, S_IFREG | S_IRWXUGO, 0);
791 if (!inode)
792 goto out_file;
793
794 d_instantiate(dentry, inode);
795 inode->i_size = size;
796 inode->i_nlink = 0;
797 file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
798 file->f_dentry = dentry;
799 file->f_mapping = inode->i_mapping;
800 file->f_op = &hugetlbfs_file_operations;
801 file->f_mode = FMODE_WRITE | FMODE_READ;
802 return file;
803
804out_file:
805 put_filp(file);
806out_dentry:
807 dput(dentry);
808out_shm_unlock:
809 user_shm_unlock(size, current->user);
810 return ERR_PTR(error);
811}
812
813static int __init init_hugetlbfs_fs(void)
814{
815 int error;
816 struct vfsmount *vfsmount;
817
818 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
819 sizeof(struct hugetlbfs_inode_info),
820 0, 0, init_once, NULL);
821 if (hugetlbfs_inode_cachep == NULL)
822 return -ENOMEM;
823
824 error = register_filesystem(&hugetlbfs_fs_type);
825 if (error)
826 goto out;
827
828 vfsmount = kern_mount(&hugetlbfs_fs_type);
829
830 if (!IS_ERR(vfsmount)) {
831 hugetlbfs_vfsmount = vfsmount;
832 return 0;
833 }
834
835 error = PTR_ERR(vfsmount);
836
837 out:
838 if (error)
839 kmem_cache_destroy(hugetlbfs_inode_cachep);
840 return error;
841}
842
843static void __exit exit_hugetlbfs_fs(void)
844{
845 kmem_cache_destroy(hugetlbfs_inode_cachep);
846 unregister_filesystem(&hugetlbfs_fs_type);
847}
848
849module_init(init_hugetlbfs_fs)
850module_exit(exit_hugetlbfs_fs)
851
852MODULE_LICENSE("GPL");
kernel source for telekom puls (alcatel/mediatek)