summaryrefslogtreecommitdiffstats
path: root/block/bio-integrity.c
blob: 63f72f00c72eef45640d68fad4579fca271235ed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
/*
 * bio-integrity.c - bio data integrity extensions
 *
 * Copyright (C) 2007, 2008, 2009 Oracle Corporation
 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA.
 *
 */

#include <linux/blkdev.h>
#include <linux/mempool.h>
#include <linux/export.h>
#include <linux/bio.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include "blk.h"

#define BIP_INLINE_VECS	4

static struct kmem_cache *bip_slab;
static struct workqueue_struct *kintegrityd_wq;

void blk_flush_integrity(void)
{
	flush_workqueue(kintegrityd_wq);
}

/**
 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
 * @bio:	bio to attach integrity metadata to
 * @gfp_mask:	Memory allocation mask
 * @nr_vecs:	Number of integrity metadata scatter-gather elements
 *
 * Description: This function prepares a bio for attaching integrity
 * metadata.  nr_vecs specifies the maximum number of pages containing
 * integrity metadata that can be attached.
 */
struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
						  gfp_t gfp_mask,
						  unsigned int nr_vecs)
{
	struct bio_integrity_payload *bip;
	struct bio_set *bs = bio->bi_pool;
	unsigned inline_vecs;

	if (!bs || !bs->bio_integrity_pool) {
		bip = kmalloc(sizeof(struct bio_integrity_payload) +
			      sizeof(struct bio_vec) * nr_vecs, gfp_mask);
		inline_vecs = nr_vecs;
	} else {
		bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
		inline_vecs = BIP_INLINE_VECS;
	}

	if (unlikely(!bip))
		return ERR_PTR(-ENOMEM);

	memset(bip, 0, sizeof(*bip));

	if (nr_vecs > inline_vecs) {
		unsigned long idx = 0;

		bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
					  bs->bvec_integrity_pool);
		if (!bip->bip_vec)
			goto err;
		bip->bip_max_vcnt = bvec_nr_vecs(idx);
		bip->bip_slab = idx;
	} else {
		bip->bip_vec = bip->bip_inline_vecs;
		bip->bip_max_vcnt = inline_vecs;
	}

	bip->bip_bio = bio;
	bio->bi_integrity = bip;
	bio->bi_opf |= REQ_INTEGRITY;

	return bip;
err:
	mempool_free(bip, bs->bio_integrity_pool);
	return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL(bio_integrity_alloc);

/**
 * bio_integrity_free - Free bio integrity payload
 * @bio:	bio containing bip to be freed
 *
 * Description: Used to free the integrity portion of a bio. Usually
 * called from bio_free().
 */
void bio_integrity_free(struct bio *bio)
{
	struct bio_integrity_payload *bip = bio_integrity(bio);
	struct bio_set *bs = bio->bi_pool;

	if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
		kfree(page_address(bip->bip_vec->bv_page) +
		      bip->bip_vec->bv_offset);

	if (bs && bs->bio_integrity_pool) {
		bvec_free(bs->bvec_integrity_pool, bip->bip_vec, bip->bip_slab);

		mempool_free(bip, bs->bio_integrity_pool);
	} else {
		kfree(bip);
	}

	bio->bi_integrity = NULL;
}
EXPORT_SYMBOL(bio_integrity_free);

/**
 * bio_integrity_add_page - Attach integrity metadata
 * @bio:	bio to update
 * @page:	page containing integrity metadata
 * @len:	number of bytes of integrity metadata in page
 * @offset:	start offset within page
 *
 * Description: Attach a page containing integrity metadata to bio.
 */
int bio_integrity_add_page(struct bio *bio, struct page *page,
			   unsigned int len, unsigned int offset)
{
	struct bio_integrity_payload *bip = bio_integrity(bio);
	struct bio_vec *iv;

	if (bip->bip_vcnt >= bip->bip_max_vcnt) {
		printk(KERN_ERR "%s: bip_vec full\n", __func__);
		return 0;
	}

	iv = bip->bip_vec + bip->bip_vcnt;

	if (bip->bip_vcnt &&
	    bvec_gap_to_prev(bdev_get_queue(bio->bi_bdev),
			     &bip->bip_vec[bip->bip_vcnt - 1], offset))
		return 0;

	iv->bv_page = page;
	iv->bv_len = len;
	iv->bv_offset = offset;
	bip->bip_vcnt++;

	return len;
}
EXPORT_SYMBOL(bio_integrity_add_page);

/**
 * bio_integrity_enabled - Check whether integrity can be passed
 * @bio:	bio to check
 *
 * Description: Determines whether bio_integrity_prep() can be called
 * on this bio or not.	bio data direction and target device must be
 * set prior to calling.  The functions honors the write_generate and
 * read_verify flags in sysfs.
 */
bool bio_integrity_enabled(struct bio *bio)
{
	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);

	if (!bio_is_rw(bio))
		return false;

	/* Already protected? */
	if (bio_integrity(bio))
		return false;

	if (bi == NULL)
		return false;

	if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL &&
	    (bi->flags & BLK_INTEGRITY_VERIFY))
		return true;

	if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL &&
	    (bi->flags & BLK_INTEGRITY_GENERATE))
		return true;

	return false;
}
EXPORT_SYMBOL(bio_integrity_enabled);

/**
 * bio_integrity_intervals - Return number of integrity intervals for a bio
 * @bi:		blk_integrity profile for device
 * @sectors:	Size of the bio in 512-byte sectors
 *
 * Description: The block layer calculates everything in 512 byte
 * sectors but integrity metadata is done in terms of the data integrity
 * interval size of the storage device.  Convert the block layer sectors
 * to the appropriate number of integrity intervals.
 */
static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
						   unsigned int sectors)
{
	return sectors >> (bi->interval_exp - 9);
}

static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
					       unsigned int sectors)
{
	return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
}

/**
 * bio_integrity_process - Process integrity metadata for a bio
 * @bio:	bio to generate/verify integrity metadata for
 * @proc_fn:	Pointer to the relevant processing function
 */
static int bio_integrity_process(struct bio *bio,
				 integrity_processing_fn *proc_fn)
{
	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
	struct blk_integrity_iter iter;
	struct bvec_iter bviter;
	struct bio_vec bv;
	struct bio_integrity_payload *bip = bio_integrity(bio);
	unsigned int ret = 0;
	void *prot_buf = page_address(bip->bip_vec->bv_page) +
		bip->bip_vec->bv_offset;

	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
	iter.interval = 1 << bi->interval_exp;
	iter.seed = bip_get_seed(bip);
	iter.prot_buf = prot_buf;

	bio_for_each_segment(bv, bio, bviter) {
		void *kaddr = kmap_atomic(bv.bv_page);

		iter.data_buf = kaddr + bv.bv_offset;
		iter.data_size = bv.bv_len;

		ret = proc_fn(&iter);
		if (ret) {
			kunmap_atomic(kaddr);
			return ret;
		}

		kunmap_atomic(kaddr);
	}
	return ret;
}

/**
 * bio_integrity_prep - Prepare bio for integrity I/O
 * @bio:	bio to prepare
 *
 * Description: Allocates a buffer for integrity metadata, maps the
 * pages and attaches them to a bio.  The bio must have data
 * direction, target device and start sector set priot to calling.  In
 * the WRITE case, integrity metadata will be generated using the
 * block device's integrity function.  In the READ case, the buffer
 * will be prepared for DMA and a suitable end_io handler set up.
 */
int bio_integrity_prep(struct bio *bio)
{
	struct bio_integrity_payload *bip;
	struct blk_integrity *bi;
	struct request_queue *q;
	void *buf;
	unsigned long start, end;
	unsigned int len, nr_pages;
	unsigned int bytes, offset, i;
	unsigned int intervals;

	bi = bdev_get_integrity(bio->bi_bdev);
	q = bdev_get_queue(bio->bi_bdev);
	BUG_ON(bi == NULL);
	BUG_ON(bio_integrity(bio));

	intervals = bio_integrity_intervals(bi, bio_sectors(bio));

	/* Allocate kernel buffer for protection data */
	len = intervals * bi->tuple_size;
	buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
	if (unlikely(buf == NULL)) {
		printk(KERN_ERR "could not allocate integrity buffer\n");
		return -ENOMEM;
	}

	end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
	start = ((unsigned long) buf) >> PAGE_SHIFT;
	nr_pages = end - start;

	/* Allocate bio integrity payload and integrity vectors */
	bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
	if (IS_ERR(bip)) {
		printk(KERN_ERR "could not allocate data integrity bioset\n");
		kfree(buf);
		return PTR_ERR(bip);
	}

	bip->bip_flags |= BIP_BLOCK_INTEGRITY;
	bip->bip_iter.bi_size = len;
	bip_set_seed(bip, bio->bi_iter.bi_sector);

	if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
		bip->bip_flags |= BIP_IP_CHECKSUM;

	/* Map it */
	offset = offset_in_page(buf);
	for (i = 0 ; i < nr_pages ; i++) {
		int ret;
		bytes = PAGE_SIZE - offset;

		if (len <= 0)
			break;

		if (bytes > len)
			bytes = len;

		ret = bio_integrity_add_page(bio, virt_to_page(buf),
					     bytes, offset);

		if (ret == 0)
			return 0;

		if (ret < bytes)
			break;

		buf += bytes;
		len -= bytes;
		offset = 0;
	}

	/* Install custom I/O completion handler if read verify is enabled */
	if (bio_data_dir(bio) == READ) {
		bip->bip_end_io = bio->bi_end_io;
		bio->bi_end_io = bio_integrity_endio;
	}

	/* Auto-generate integrity metadata if this is a write */
	if (bio_data_dir(bio) == WRITE)
		bio_integrity_process(bio, bi->profile->generate_fn);

	return 0;
}
EXPORT_SYMBOL(bio_integrity_prep);

/**
 * bio_integrity_verify_fn - Integrity I/O completion worker
 * @work:	Work struct stored in bio to be verified
 *
 * Description: This workqueue function is called to complete a READ
 * request.  The function verifies the transferred integrity metadata
 * and then calls the original bio end_io function.
 */
static void bio_integrity_verify_fn(struct work_struct *work)
{
	struct bio_integrity_payload *bip =
		container_of(work, struct bio_integrity_payload, bip_work);
	struct bio *bio = bip->bip_bio;
	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);

	bio->bi_error = bio_integrity_process(bio, bi->profile->verify_fn);

	/* Restore original bio completion handler */
	bio->bi_end_io = bip->bip_end_io;
	bio_endio(bio);
}

/**
 * bio_integrity_endio - Integrity I/O completion function
 * @bio:	Protected bio
 * @error:	Pointer to errno
 *
 * Description: Completion for integrity I/O
 *
 * Normally I/O completion is done in interrupt context.  However,
 * verifying I/O integrity is a time-consuming task which must be run
 * in process context.	This function postpones completion
 * accordingly.
 */
void bio_integrity_endio(struct bio *bio)
{
	struct bio_integrity_payload *bip = bio_integrity(bio);

	BUG_ON(bip->bip_bio != bio);

	/* In case of an I/O error there is no point in verifying the
	 * integrity metadata.  Restore original bio end_io handler
	 * and run it.
	 */
	if (bio->bi_error) {
		bio->bi_end_io = bip->bip_end_io;
		bio_endio(bio);

		return;
	}

	INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
	queue_work(kintegrityd_wq, &bip->bip_work);
}
EXPORT_SYMBOL(bio_integrity_endio);

/**
 * bio_integrity_advance - Advance integrity vector
 * @bio:	bio whose integrity vector to update
 * @bytes_done:	number of data bytes that have been completed
 *
 * Description: This function calculates how many integrity bytes the
 * number of completed data bytes correspond to and advances the
 * integrity vector accordingly.
 */
void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
{
	struct bio_integrity_payload *bip = bio_integrity(bio);
	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
	unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);

	bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
}
EXPORT_SYMBOL(bio_integrity_advance);

/**
 * bio_integrity_trim - Trim integrity vector
 * @bio:	bio whose integrity vector to update
 * @offset:	offset to first data sector
 * @sectors:	number of data sectors
 *
 * Description: Used to trim the integrity vector in a cloned bio.
 * The ivec will be advanced corresponding to 'offset' data sectors
 * and the length will be truncated corresponding to 'len' data
 * sectors.
 */
void bio_integrity_trim(struct bio *bio, unsigned int offset,
			unsigned int sectors)
{
	struct bio_integrity_payload *bip = bio_integrity(bio);
	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);

	bio_integrity_advance(bio, offset << 9);
	bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
}
EXPORT_SYMBOL(bio_integrity_trim);

/**
 * bio_integrity_clone - Callback for cloning bios with integrity metadata
 * @bio:	New bio
 * @bio_src:	Original bio
 * @gfp_mask:	Memory allocation mask
 *
 * Description:	Called to allocate a bip when cloning a bio
 */
int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
			gfp_t gfp_mask)
{
	struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
	struct bio_integrity_payload *bip;

	BUG_ON(bip_src == NULL);

	bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
	if (IS_ERR(bip))
		return PTR_ERR(bip);

	memcpy(bip->bip_vec, bip_src->bip_vec,
	       bip_src->bip_vcnt * sizeof(struct bio_vec));

	bip->bip_vcnt = bip_src->bip_vcnt;
	bip->bip_iter = bip_src->bip_iter;

	return 0;
}
EXPORT_SYMBOL(bio_integrity_clone);

int bioset_integrity_create(struct bio_set *bs, int pool_size)
{
	if (bs->bio_integrity_pool)
		return 0;

	bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
	if (!bs->bio_integrity_pool)
		return -1;

	bs->bvec_integrity_pool = biovec_create_pool(pool_size);
	if (!bs->bvec_integrity_pool) {
		mempool_destroy(bs->bio_integrity_pool);
		return -1;
	}

	return 0;
}
EXPORT_SYMBOL(bioset_integrity_create);

void bioset_integrity_free(struct bio_set *bs)
{
	if (bs->bio_integrity_pool)
		mempool_destroy(bs->bio_integrity_pool);

	if (bs->bvec_integrity_pool)
		mempool_destroy(bs->bvec_integrity_pool);
}
EXPORT_SYMBOL(bioset_integrity_free);

void __init bio_integrity_init(void)
{
	/*
	 * kintegrityd won't block much but may burn a lot of CPU cycles.
	 * Make it highpri CPU intensive wq with max concurrency of 1.
	 */
	kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
					 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
	if (!kintegrityd_wq)
		panic("Failed to create kintegrityd\n");

	bip_slab = kmem_cache_create("bio_integrity_payload",
				     sizeof(struct bio_integrity_payload) +
				     sizeof(struct bio_vec) * BIP_INLINE_VECS,
				     0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
}
OpenPOWER on IntegriCloud