blob: 1a8962569b5caecf81344e5a905a6c9ad68ec4ab [file] [log] [blame]
Jaegeuk Kim0b81d072015-05-15 16:26:10 -07001/*
2 * This contains encryption functions for per-file encryption.
3 *
4 * Copyright (C) 2015, Google, Inc.
5 * Copyright (C) 2015, Motorola Mobility
6 *
7 * Written by Michael Halcrow, 2014.
8 *
9 * Filename encryption additions
10 * Uday Savagaonkar, 2014
11 * Encryption policy handling additions
12 * Ildar Muslukhov, 2014
13 * Add fscrypt_pullback_bio_page()
14 * Jaegeuk Kim, 2015.
15 *
16 * This has not yet undergone a rigorous security audit.
17 *
18 * The usage of AES-XTS should conform to recommendations in NIST
19 * Special Publication 800-38E and IEEE P1619/D16.
20 */
21
Jaegeuk Kim0b81d072015-05-15 16:26:10 -070022#include <linux/pagemap.h>
23#include <linux/mempool.h>
24#include <linux/module.h>
25#include <linux/scatterlist.h>
26#include <linux/ratelimit.h>
27#include <linux/bio.h>
28#include <linux/dcache.h>
Jaegeuk Kim03a8bb02016-04-12 16:05:36 -070029#include <linux/namei.h>
Jaegeuk Kim0b81d072015-05-15 16:26:10 -070030#include <linux/fscrypto.h>
31
32static unsigned int num_prealloc_crypto_pages = 32;
33static unsigned int num_prealloc_crypto_ctxs = 128;
34
35module_param(num_prealloc_crypto_pages, uint, 0444);
36MODULE_PARM_DESC(num_prealloc_crypto_pages,
37 "Number of crypto pages to preallocate");
38module_param(num_prealloc_crypto_ctxs, uint, 0444);
39MODULE_PARM_DESC(num_prealloc_crypto_ctxs,
40 "Number of crypto contexts to preallocate");
41
42static mempool_t *fscrypt_bounce_page_pool = NULL;
43
44static LIST_HEAD(fscrypt_free_ctxs);
45static DEFINE_SPINLOCK(fscrypt_ctx_lock);
46
47static struct workqueue_struct *fscrypt_read_workqueue;
48static DEFINE_MUTEX(fscrypt_init_mutex);
49
50static struct kmem_cache *fscrypt_ctx_cachep;
51struct kmem_cache *fscrypt_info_cachep;
52
53/**
54 * fscrypt_release_ctx() - Releases an encryption context
55 * @ctx: The encryption context to release.
56 *
57 * If the encryption context was allocated from the pre-allocated pool, returns
58 * it to that pool. Else, frees it.
59 *
60 * If there's a bounce page in the context, this frees that.
61 */
62void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
63{
64 unsigned long flags;
65
66 if (ctx->flags & FS_WRITE_PATH_FL && ctx->w.bounce_page) {
67 mempool_free(ctx->w.bounce_page, fscrypt_bounce_page_pool);
68 ctx->w.bounce_page = NULL;
69 }
70 ctx->w.control_page = NULL;
71 if (ctx->flags & FS_CTX_REQUIRES_FREE_ENCRYPT_FL) {
72 kmem_cache_free(fscrypt_ctx_cachep, ctx);
73 } else {
74 spin_lock_irqsave(&fscrypt_ctx_lock, flags);
75 list_add(&ctx->free_list, &fscrypt_free_ctxs);
76 spin_unlock_irqrestore(&fscrypt_ctx_lock, flags);
77 }
78}
79EXPORT_SYMBOL(fscrypt_release_ctx);
80
81/**
82 * fscrypt_get_ctx() - Gets an encryption context
83 * @inode: The inode for which we are doing the crypto
Jaegeuk Kimb32e4482016-04-11 15:51:57 -070084 * @gfp_flags: The gfp flag for memory allocation
Jaegeuk Kim0b81d072015-05-15 16:26:10 -070085 *
86 * Allocates and initializes an encryption context.
87 *
88 * Return: An allocated and initialized encryption context on success; error
89 * value or NULL otherwise.
90 */
Jaegeuk Kimb32e4482016-04-11 15:51:57 -070091struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags)
Jaegeuk Kim0b81d072015-05-15 16:26:10 -070092{
93 struct fscrypt_ctx *ctx = NULL;
94 struct fscrypt_info *ci = inode->i_crypt_info;
95 unsigned long flags;
96
97 if (ci == NULL)
98 return ERR_PTR(-ENOKEY);
99
100 /*
101 * We first try getting the ctx from a free list because in
102 * the common case the ctx will have an allocated and
103 * initialized crypto tfm, so it's probably a worthwhile
104 * optimization. For the bounce page, we first try getting it
105 * from the kernel allocator because that's just about as fast
106 * as getting it from a list and because a cache of free pages
107 * should generally be a "last resort" option for a filesystem
108 * to be able to do its job.
109 */
110 spin_lock_irqsave(&fscrypt_ctx_lock, flags);
111 ctx = list_first_entry_or_null(&fscrypt_free_ctxs,
112 struct fscrypt_ctx, free_list);
113 if (ctx)
114 list_del(&ctx->free_list);
115 spin_unlock_irqrestore(&fscrypt_ctx_lock, flags);
116 if (!ctx) {
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700117 ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, gfp_flags);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700118 if (!ctx)
119 return ERR_PTR(-ENOMEM);
120 ctx->flags |= FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
121 } else {
122 ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
123 }
124 ctx->flags &= ~FS_WRITE_PATH_FL;
125 return ctx;
126}
127EXPORT_SYMBOL(fscrypt_get_ctx);
128
129/**
Eric Biggers53fd7552016-09-15 16:51:01 -0400130 * page_crypt_complete() - completion callback for page crypto
131 * @req: The asynchronous cipher request context
132 * @res: The result of the cipher operation
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700133 */
Eric Biggers53fd7552016-09-15 16:51:01 -0400134static void page_crypt_complete(struct crypto_async_request *req, int res)
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700135{
136 struct fscrypt_completion_result *ecr = req->data;
137
138 if (res == -EINPROGRESS)
139 return;
140 ecr->res = res;
141 complete(&ecr->completion);
142}
143
144typedef enum {
145 FS_DECRYPT = 0,
146 FS_ENCRYPT,
147} fscrypt_direction_t;
148
149static int do_page_crypto(struct inode *inode,
150 fscrypt_direction_t rw, pgoff_t index,
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700151 struct page *src_page, struct page *dest_page,
152 gfp_t gfp_flags)
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700153{
Eric Biggersfb445432016-10-12 23:30:16 -0400154 struct {
155 __le64 index;
156 u8 padding[FS_XTS_TWEAK_SIZE - sizeof(__le64)];
157 } xts_tweak;
Linus Torvaldsd4075742016-03-21 11:03:02 -0700158 struct skcipher_request *req = NULL;
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700159 DECLARE_FS_COMPLETION_RESULT(ecr);
160 struct scatterlist dst, src;
161 struct fscrypt_info *ci = inode->i_crypt_info;
Linus Torvaldsd4075742016-03-21 11:03:02 -0700162 struct crypto_skcipher *tfm = ci->ci_ctfm;
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700163 int res = 0;
164
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700165 req = skcipher_request_alloc(tfm, gfp_flags);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700166 if (!req) {
167 printk_ratelimited(KERN_ERR
168 "%s: crypto_request_alloc() failed\n",
169 __func__);
170 return -ENOMEM;
171 }
172
Linus Torvaldsd4075742016-03-21 11:03:02 -0700173 skcipher_request_set_callback(
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700174 req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
Eric Biggers53fd7552016-09-15 16:51:01 -0400175 page_crypt_complete, &ecr);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700176
Eric Biggersfb445432016-10-12 23:30:16 -0400177 BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE);
178 xts_tweak.index = cpu_to_le64(index);
179 memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700180
181 sg_init_table(&dst, 1);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300182 sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700183 sg_init_table(&src, 1);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300184 sg_set_page(&src, src_page, PAGE_SIZE, 0);
Eric Biggersfb445432016-10-12 23:30:16 -0400185 skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700186 if (rw == FS_DECRYPT)
Linus Torvaldsd4075742016-03-21 11:03:02 -0700187 res = crypto_skcipher_decrypt(req);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700188 else
Linus Torvaldsd4075742016-03-21 11:03:02 -0700189 res = crypto_skcipher_encrypt(req);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700190 if (res == -EINPROGRESS || res == -EBUSY) {
191 BUG_ON(req->base.data != &ecr);
192 wait_for_completion(&ecr.completion);
193 res = ecr.res;
194 }
Linus Torvaldsd4075742016-03-21 11:03:02 -0700195 skcipher_request_free(req);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700196 if (res) {
197 printk_ratelimited(KERN_ERR
Linus Torvaldsd4075742016-03-21 11:03:02 -0700198 "%s: crypto_skcipher_encrypt() returned %d\n",
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700199 __func__, res);
200 return res;
201 }
202 return 0;
203}
204
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700205static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700206{
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700207 ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700208 if (ctx->w.bounce_page == NULL)
209 return ERR_PTR(-ENOMEM);
210 ctx->flags |= FS_WRITE_PATH_FL;
211 return ctx->w.bounce_page;
212}
213
214/**
215 * fscypt_encrypt_page() - Encrypts a page
216 * @inode: The inode for which the encryption should take place
217 * @plaintext_page: The page to encrypt. Must be locked.
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700218 * @gfp_flags: The gfp flag for memory allocation
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700219 *
220 * Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
221 * encryption context.
222 *
223 * Called on the page write path. The caller must call
224 * fscrypt_restore_control_page() on the returned ciphertext page to
225 * release the bounce buffer and the encryption context.
226 *
227 * Return: An allocated page with the encrypted content on success. Else, an
228 * error value or NULL.
229 */
230struct page *fscrypt_encrypt_page(struct inode *inode,
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700231 struct page *plaintext_page, gfp_t gfp_flags)
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700232{
233 struct fscrypt_ctx *ctx;
234 struct page *ciphertext_page = NULL;
235 int err;
236
237 BUG_ON(!PageLocked(plaintext_page));
238
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700239 ctx = fscrypt_get_ctx(inode, gfp_flags);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700240 if (IS_ERR(ctx))
241 return (struct page *)ctx;
242
243 /* The encryption operation will require a bounce page. */
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700244 ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700245 if (IS_ERR(ciphertext_page))
246 goto errout;
247
248 ctx->w.control_page = plaintext_page;
249 err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index,
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700250 plaintext_page, ciphertext_page,
251 gfp_flags);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700252 if (err) {
253 ciphertext_page = ERR_PTR(err);
254 goto errout;
255 }
256 SetPagePrivate(ciphertext_page);
257 set_page_private(ciphertext_page, (unsigned long)ctx);
258 lock_page(ciphertext_page);
259 return ciphertext_page;
260
261errout:
262 fscrypt_release_ctx(ctx);
263 return ciphertext_page;
264}
265EXPORT_SYMBOL(fscrypt_encrypt_page);
266
267/**
268 * f2crypt_decrypt_page() - Decrypts a page in-place
269 * @page: The page to decrypt. Must be locked.
270 *
271 * Decrypts page in-place using the ctx encryption context.
272 *
273 * Called from the read completion callback.
274 *
275 * Return: Zero on success, non-zero otherwise.
276 */
277int fscrypt_decrypt_page(struct page *page)
278{
279 BUG_ON(!PageLocked(page));
280
281 return do_page_crypto(page->mapping->host,
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700282 FS_DECRYPT, page->index, page, page, GFP_NOFS);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700283}
284EXPORT_SYMBOL(fscrypt_decrypt_page);
285
286int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
287 sector_t pblk, unsigned int len)
288{
289 struct fscrypt_ctx *ctx;
290 struct page *ciphertext_page = NULL;
291 struct bio *bio;
292 int ret, err = 0;
293
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300294 BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700295
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700296 ctx = fscrypt_get_ctx(inode, GFP_NOFS);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700297 if (IS_ERR(ctx))
298 return PTR_ERR(ctx);
299
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700300 ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700301 if (IS_ERR(ciphertext_page)) {
302 err = PTR_ERR(ciphertext_page);
303 goto errout;
304 }
305
306 while (len--) {
307 err = do_page_crypto(inode, FS_ENCRYPT, lblk,
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700308 ZERO_PAGE(0), ciphertext_page,
309 GFP_NOFS);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700310 if (err)
311 goto errout;
312
Jaegeuk Kimb32e4482016-04-11 15:51:57 -0700313 bio = bio_alloc(GFP_NOWAIT, 1);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700314 if (!bio) {
315 err = -ENOMEM;
316 goto errout;
317 }
318 bio->bi_bdev = inode->i_sb->s_bdev;
319 bio->bi_iter.bi_sector =
320 pblk << (inode->i_sb->s_blocksize_bits - 9);
Mike Christie95fe6c12016-06-05 14:31:48 -0500321 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700322 ret = bio_add_page(bio, ciphertext_page,
323 inode->i_sb->s_blocksize, 0);
324 if (ret != inode->i_sb->s_blocksize) {
325 /* should never happen! */
326 WARN_ON(1);
327 bio_put(bio);
328 err = -EIO;
329 goto errout;
330 }
Mike Christie4e49ea42016-06-05 14:31:41 -0500331 err = submit_bio_wait(bio);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700332 if ((err == 0) && bio->bi_error)
333 err = -EIO;
334 bio_put(bio);
335 if (err)
336 goto errout;
337 lblk++;
338 pblk++;
339 }
340 err = 0;
341errout:
342 fscrypt_release_ctx(ctx);
343 return err;
344}
345EXPORT_SYMBOL(fscrypt_zeroout_range);
346
347/*
348 * Validate dentries for encrypted directories to make sure we aren't
349 * potentially caching stale data after a key has been added or
350 * removed.
351 */
352static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
353{
Jaegeuk Kimd7d75352016-04-11 15:10:11 -0700354 struct dentry *dir;
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700355 int dir_has_key, cached_with_key;
356
Jaegeuk Kim03a8bb02016-04-12 16:05:36 -0700357 if (flags & LOOKUP_RCU)
358 return -ECHILD;
359
Jaegeuk Kimd7d75352016-04-11 15:10:11 -0700360 dir = dget_parent(dentry);
361 if (!d_inode(dir)->i_sb->s_cop->is_encrypted(d_inode(dir))) {
362 dput(dir);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700363 return 0;
Jaegeuk Kimd7d75352016-04-11 15:10:11 -0700364 }
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700365
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700366 /* this should eventually be an flag in d_flags */
367 spin_lock(&dentry->d_lock);
368 cached_with_key = dentry->d_flags & DCACHE_ENCRYPTED_WITH_KEY;
369 spin_unlock(&dentry->d_lock);
Eric Biggers2984e522017-02-21 15:07:11 -0800370 dir_has_key = (d_inode(dir)->i_crypt_info != NULL);
Jaegeuk Kimd7d75352016-04-11 15:10:11 -0700371 dput(dir);
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700372
373 /*
374 * If the dentry was cached without the key, and it is a
375 * negative dentry, it might be a valid name. We can't check
376 * if the key has since been made available due to locking
377 * reasons, so we fail the validation so ext4_lookup() can do
378 * this check.
379 *
380 * We also fail the validation if the dentry was created with
381 * the key present, but we no longer have the key, or vice versa.
382 */
383 if ((!cached_with_key && d_is_negative(dentry)) ||
384 (!cached_with_key && dir_has_key) ||
385 (cached_with_key && !dir_has_key))
386 return 0;
387 return 1;
388}
389
390const struct dentry_operations fscrypt_d_ops = {
391 .d_revalidate = fscrypt_d_revalidate,
392};
393EXPORT_SYMBOL(fscrypt_d_ops);
394
395/*
396 * Call fscrypt_decrypt_page on every single page, reusing the encryption
397 * context.
398 */
399static void completion_pages(struct work_struct *work)
400{
401 struct fscrypt_ctx *ctx =
402 container_of(work, struct fscrypt_ctx, r.work);
403 struct bio *bio = ctx->r.bio;
404 struct bio_vec *bv;
405 int i;
406
407 bio_for_each_segment_all(bv, bio, i) {
408 struct page *page = bv->bv_page;
409 int ret = fscrypt_decrypt_page(page);
410
411 if (ret) {
412 WARN_ON_ONCE(1);
413 SetPageError(page);
414 } else {
415 SetPageUptodate(page);
416 }
417 unlock_page(page);
418 }
419 fscrypt_release_ctx(ctx);
420 bio_put(bio);
421}
422
423void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
424{
425 INIT_WORK(&ctx->r.work, completion_pages);
426 ctx->r.bio = bio;
427 queue_work(fscrypt_read_workqueue, &ctx->r.work);
428}
429EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
430
431void fscrypt_pullback_bio_page(struct page **page, bool restore)
432{
433 struct fscrypt_ctx *ctx;
434 struct page *bounce_page;
435
436 /* The bounce data pages are unmapped. */
437 if ((*page)->mapping)
438 return;
439
440 /* The bounce data page is unmapped. */
441 bounce_page = *page;
442 ctx = (struct fscrypt_ctx *)page_private(bounce_page);
443
444 /* restore control page */
445 *page = ctx->w.control_page;
446
447 if (restore)
448 fscrypt_restore_control_page(bounce_page);
449}
450EXPORT_SYMBOL(fscrypt_pullback_bio_page);
451
452void fscrypt_restore_control_page(struct page *page)
453{
454 struct fscrypt_ctx *ctx;
455
456 ctx = (struct fscrypt_ctx *)page_private(page);
457 set_page_private(page, (unsigned long)NULL);
458 ClearPagePrivate(page);
459 unlock_page(page);
460 fscrypt_release_ctx(ctx);
461}
462EXPORT_SYMBOL(fscrypt_restore_control_page);
463
464static void fscrypt_destroy(void)
465{
466 struct fscrypt_ctx *pos, *n;
467
468 list_for_each_entry_safe(pos, n, &fscrypt_free_ctxs, free_list)
469 kmem_cache_free(fscrypt_ctx_cachep, pos);
470 INIT_LIST_HEAD(&fscrypt_free_ctxs);
471 mempool_destroy(fscrypt_bounce_page_pool);
472 fscrypt_bounce_page_pool = NULL;
473}
474
475/**
476 * fscrypt_initialize() - allocate major buffers for fs encryption.
477 *
478 * We only call this when we start accessing encrypted files, since it
479 * results in memory getting allocated that wouldn't otherwise be used.
480 *
481 * Return: Zero on success, non-zero otherwise.
482 */
483int fscrypt_initialize(void)
484{
485 int i, res = -ENOMEM;
486
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700487 mutex_lock(&fscrypt_init_mutex);
488 if (fscrypt_bounce_page_pool)
489 goto already_initialized;
490
491 for (i = 0; i < num_prealloc_crypto_ctxs; i++) {
492 struct fscrypt_ctx *ctx;
493
494 ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, GFP_NOFS);
495 if (!ctx)
496 goto fail;
497 list_add(&ctx->free_list, &fscrypt_free_ctxs);
498 }
499
500 fscrypt_bounce_page_pool =
501 mempool_create_page_pool(num_prealloc_crypto_pages, 0);
502 if (!fscrypt_bounce_page_pool)
503 goto fail;
504
505already_initialized:
506 mutex_unlock(&fscrypt_init_mutex);
507 return 0;
508fail:
509 fscrypt_destroy();
510 mutex_unlock(&fscrypt_init_mutex);
511 return res;
512}
513EXPORT_SYMBOL(fscrypt_initialize);
514
515/**
516 * fscrypt_init() - Set up for fs encryption.
517 */
518static int __init fscrypt_init(void)
519{
Eric Biggers3ce14632018-04-20 16:30:02 -0700520 /*
521 * Use an unbound workqueue to allow bios to be decrypted in parallel
522 * even when they happen to complete on the same CPU. This sacrifices
523 * locality, but it's worthwhile since decryption is CPU-intensive.
524 *
525 * Also use a high-priority workqueue to prioritize decryption work,
526 * which blocks reads from completing, over regular application tasks.
527 */
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700528 fscrypt_read_workqueue = alloc_workqueue("fscrypt_read_queue",
Eric Biggers3ce14632018-04-20 16:30:02 -0700529 WQ_UNBOUND | WQ_HIGHPRI,
530 num_online_cpus());
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700531 if (!fscrypt_read_workqueue)
532 goto fail;
533
534 fscrypt_ctx_cachep = KMEM_CACHE(fscrypt_ctx, SLAB_RECLAIM_ACCOUNT);
535 if (!fscrypt_ctx_cachep)
536 goto fail_free_queue;
537
538 fscrypt_info_cachep = KMEM_CACHE(fscrypt_info, SLAB_RECLAIM_ACCOUNT);
539 if (!fscrypt_info_cachep)
540 goto fail_free_ctx;
541
542 return 0;
543
544fail_free_ctx:
545 kmem_cache_destroy(fscrypt_ctx_cachep);
546fail_free_queue:
547 destroy_workqueue(fscrypt_read_workqueue);
548fail:
549 return -ENOMEM;
550}
551module_init(fscrypt_init)
552
553/**
554 * fscrypt_exit() - Shutdown the fs encryption system
555 */
556static void __exit fscrypt_exit(void)
557{
558 fscrypt_destroy();
559
560 if (fscrypt_read_workqueue)
561 destroy_workqueue(fscrypt_read_workqueue);
562 kmem_cache_destroy(fscrypt_ctx_cachep);
563 kmem_cache_destroy(fscrypt_info_cachep);
564}
565module_exit(fscrypt_exit);
566
567MODULE_LICENSE("GPL");