1// SPDX-License-Identifier: GPL-2.0
2/*
3 * blk-integrity.c - Block layer data integrity extensions
4 *
5 * Copyright (C) 2007, 2008 Oracle Corporation
6 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
7 */
8
9#include <linux/blk-integrity.h>
10#include <linux/backing-dev.h>
11#include <linux/mempool.h>
12#include <linux/bio.h>
13#include <linux/scatterlist.h>
14#include <linux/export.h>
15#include <linux/slab.h>
16
17#include "blk.h"
18
19/**
20 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
21 * @q:		request queue
22 * @bio:	bio with integrity metadata attached
23 *
24 * Description: Returns the number of elements required in a
25 * scatterlist corresponding to the integrity metadata in a bio.
26 */
27int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
28{
29	struct bio_vec iv, ivprv = { NULL };
30	unsigned int segments = 0;
31	unsigned int seg_size = 0;
32	struct bvec_iter iter;
33	int prev = 0;
34
35	bio_for_each_integrity_vec(iv, bio, iter) {
36
37		if (prev) {
38			if (!biovec_phys_mergeable(q, &ivprv, &iv))
39				goto new_segment;
40			if (seg_size + iv.bv_len > queue_max_segment_size(q))
41				goto new_segment;
42
43			seg_size += iv.bv_len;
44		} else {
45new_segment:
46			segments++;
47			seg_size = iv.bv_len;
48		}
49
50		prev = 1;
51		ivprv = iv;
52	}
53
54	return segments;
55}
56EXPORT_SYMBOL(blk_rq_count_integrity_sg);
57
58/**
59 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
60 * @q:		request queue
61 * @bio:	bio with integrity metadata attached
62 * @sglist:	target scatterlist
63 *
64 * Description: Map the integrity vectors in request into a
65 * scatterlist.  The scatterlist must be big enough to hold all
66 * elements.  I.e. sized using blk_rq_count_integrity_sg().
67 */
68int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
69			    struct scatterlist *sglist)
70{
71	struct bio_vec iv, ivprv = { NULL };
72	struct scatterlist *sg = NULL;
73	unsigned int segments = 0;
74	struct bvec_iter iter;
75	int prev = 0;
76
77	bio_for_each_integrity_vec(iv, bio, iter) {
78
79		if (prev) {
80			if (!biovec_phys_mergeable(q, &ivprv, &iv))
81				goto new_segment;
82			if (sg->length + iv.bv_len > queue_max_segment_size(q))
83				goto new_segment;
84
85			sg->length += iv.bv_len;
86		} else {
87new_segment:
88			if (!sg)
89				sg = sglist;
90			else {
91				sg_unmark_end(sg);
92				sg = sg_next(sg);
93			}
94
95			sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset);
96			segments++;
97		}
98
99		prev = 1;
100		ivprv = iv;
101	}
102
103	if (sg)
104		sg_mark_end(sg);
105
106	return segments;
107}
108EXPORT_SYMBOL(blk_rq_map_integrity_sg);
109
110/**
111 * blk_integrity_compare - Compare integrity profile of two disks
112 * @gd1:	Disk to compare
113 * @gd2:	Disk to compare
114 *
115 * Description: Meta-devices like DM and MD need to verify that all
116 * sub-devices use the same integrity format before advertising to
117 * upper layers that they can send/receive integrity metadata.  This
118 * function can be used to check whether two gendisk devices have
119 * compatible integrity formats.
120 */
121int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
122{
123	struct blk_integrity *b1 = &gd1->queue->integrity;
124	struct blk_integrity *b2 = &gd2->queue->integrity;
125
126	if (!b1->profile && !b2->profile)
127		return 0;
128
129	if (!b1->profile || !b2->profile)
130		return -1;
131
132	if (b1->interval_exp != b2->interval_exp) {
133		pr_err("%s: %s/%s protection interval %u != %u\n",
134		       __func__, gd1->disk_name, gd2->disk_name,
135		       1 << b1->interval_exp, 1 << b2->interval_exp);
136		return -1;
137	}
138
139	if (b1->tuple_size != b2->tuple_size) {
140		pr_err("%s: %s/%s tuple sz %u != %u\n", __func__,
141		       gd1->disk_name, gd2->disk_name,
142		       b1->tuple_size, b2->tuple_size);
143		return -1;
144	}
145
146	if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) {
147		pr_err("%s: %s/%s tag sz %u != %u\n", __func__,
148		       gd1->disk_name, gd2->disk_name,
149		       b1->tag_size, b2->tag_size);
150		return -1;
151	}
152
153	if (b1->profile != b2->profile) {
154		pr_err("%s: %s/%s type %s != %s\n", __func__,
155		       gd1->disk_name, gd2->disk_name,
156		       b1->profile->name, b2->profile->name);
157		return -1;
158	}
159
160	return 0;
161}
162EXPORT_SYMBOL(blk_integrity_compare);
163
164bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
165			    struct request *next)
166{
167	if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
168		return true;
169
170	if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
171		return false;
172
173	if (bio_integrity(req->bio)->bip_flags !=
174	    bio_integrity(next->bio)->bip_flags)
175		return false;
176
177	if (req->nr_integrity_segments + next->nr_integrity_segments >
178	    q->limits.max_integrity_segments)
179		return false;
180
181	if (integrity_req_gap_back_merge(req, next->bio))
182		return false;
183
184	return true;
185}
186
187bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
188			     struct bio *bio)
189{
190	int nr_integrity_segs;
191	struct bio *next = bio->bi_next;
192
193	if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL)
194		return true;
195
196	if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL)
197		return false;
198
199	if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags)
200		return false;
201
202	bio->bi_next = NULL;
203	nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
204	bio->bi_next = next;
205
206	if (req->nr_integrity_segments + nr_integrity_segs >
207	    q->limits.max_integrity_segments)
208		return false;
209
210	req->nr_integrity_segments += nr_integrity_segs;
211
212	return true;
213}
214
215static inline struct blk_integrity *dev_to_bi(struct device *dev)
216{
217	return &dev_to_disk(dev)->queue->integrity;
218}
219
220static ssize_t format_show(struct device *dev, struct device_attribute *attr,
221			   char *page)
222{
223	struct blk_integrity *bi = dev_to_bi(dev);
224
225	if (bi->profile && bi->profile->name)
226		return sysfs_emit(page, "%s\n", bi->profile->name);
227	return sysfs_emit(page, "none\n");
228}
229
230static ssize_t tag_size_show(struct device *dev, struct device_attribute *attr,
231			     char *page)
232{
233	struct blk_integrity *bi = dev_to_bi(dev);
234
235	return sysfs_emit(page, "%u\n", bi->tag_size);
236}
237
238static ssize_t protection_interval_bytes_show(struct device *dev,
239					      struct device_attribute *attr,
240					      char *page)
241{
242	struct blk_integrity *bi = dev_to_bi(dev);
243
244	return sysfs_emit(page, "%u\n",
245			  bi->interval_exp ? 1 << bi->interval_exp : 0);
246}
247
248static ssize_t read_verify_store(struct device *dev,
249				 struct device_attribute *attr,
250				 const char *page, size_t count)
251{
252	struct blk_integrity *bi = dev_to_bi(dev);
253	char *p = (char *) page;
254	unsigned long val = simple_strtoul(p, &p, 10);
255
256	if (val)
257		bi->flags |= BLK_INTEGRITY_VERIFY;
258	else
259		bi->flags &= ~BLK_INTEGRITY_VERIFY;
260
261	return count;
262}
263
264static ssize_t read_verify_show(struct device *dev,
265				struct device_attribute *attr, char *page)
266{
267	struct blk_integrity *bi = dev_to_bi(dev);
268
269	return sysfs_emit(page, "%d\n", !!(bi->flags & BLK_INTEGRITY_VERIFY));
270}
271
272static ssize_t write_generate_store(struct device *dev,
273				    struct device_attribute *attr,
274				    const char *page, size_t count)
275{
276	struct blk_integrity *bi = dev_to_bi(dev);
277
278	char *p = (char *) page;
279	unsigned long val = simple_strtoul(p, &p, 10);
280
281	if (val)
282		bi->flags |= BLK_INTEGRITY_GENERATE;
283	else
284		bi->flags &= ~BLK_INTEGRITY_GENERATE;
285
286	return count;
287}
288
289static ssize_t write_generate_show(struct device *dev,
290				   struct device_attribute *attr, char *page)
291{
292	struct blk_integrity *bi = dev_to_bi(dev);
293
294	return sysfs_emit(page, "%d\n", !!(bi->flags & BLK_INTEGRITY_GENERATE));
295}
296
297static ssize_t device_is_integrity_capable_show(struct device *dev,
298						struct device_attribute *attr,
299						char *page)
300{
301	struct blk_integrity *bi = dev_to_bi(dev);
302
303	return sysfs_emit(page, "%u\n",
304			  !!(bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE));
305}
306
307static DEVICE_ATTR_RO(format);
308static DEVICE_ATTR_RO(tag_size);
309static DEVICE_ATTR_RO(protection_interval_bytes);
310static DEVICE_ATTR_RW(read_verify);
311static DEVICE_ATTR_RW(write_generate);
312static DEVICE_ATTR_RO(device_is_integrity_capable);
313
314static struct attribute *integrity_attrs[] = {
315	&dev_attr_format.attr,
316	&dev_attr_tag_size.attr,
317	&dev_attr_protection_interval_bytes.attr,
318	&dev_attr_read_verify.attr,
319	&dev_attr_write_generate.attr,
320	&dev_attr_device_is_integrity_capable.attr,
321	NULL
322};
323
324const struct attribute_group blk_integrity_attr_group = {
325	.name = "integrity",
326	.attrs = integrity_attrs,
327};
328
329static blk_status_t blk_integrity_nop_fn(struct blk_integrity_iter *iter)
330{
331	return BLK_STS_OK;
332}
333
334static void blk_integrity_nop_prepare(struct request *rq)
335{
336}
337
338static void blk_integrity_nop_complete(struct request *rq,
339		unsigned int nr_bytes)
340{
341}
342
343static const struct blk_integrity_profile nop_profile = {
344	.name = "nop",
345	.generate_fn = blk_integrity_nop_fn,
346	.verify_fn = blk_integrity_nop_fn,
347	.prepare_fn = blk_integrity_nop_prepare,
348	.complete_fn = blk_integrity_nop_complete,
349};
350
351/**
352 * blk_integrity_register - Register a gendisk as being integrity-capable
353 * @disk:	struct gendisk pointer to make integrity-aware
354 * @template:	block integrity profile to register
355 *
356 * Description: When a device needs to advertise itself as being able to
357 * send/receive integrity metadata it must use this function to register
358 * the capability with the block layer. The template is a blk_integrity
359 * struct with values appropriate for the underlying hardware. See
360 * Documentation/block/data-integrity.rst.
361 */
362void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
363{
364	struct blk_integrity *bi = &disk->queue->integrity;
365
366	bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
367		template->flags;
368	bi->interval_exp = template->interval_exp ? :
369		ilog2(queue_logical_block_size(disk->queue));
370	bi->profile = template->profile ? template->profile : &nop_profile;
371	bi->tuple_size = template->tuple_size;
372	bi->tag_size = template->tag_size;
373	bi->pi_offset = template->pi_offset;
374
375	blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, disk->queue);
376
377#ifdef CONFIG_BLK_INLINE_ENCRYPTION
378	if (disk->queue->crypto_profile) {
379		pr_warn("blk-integrity: Integrity and hardware inline encryption are not supported together. Disabling hardware inline encryption.\n");
380		disk->queue->crypto_profile = NULL;
381	}
382#endif
383}
384EXPORT_SYMBOL(blk_integrity_register);
385
386/**
387 * blk_integrity_unregister - Unregister block integrity profile
388 * @disk:	disk whose integrity profile to unregister
389 *
390 * Description: This function unregisters the integrity capability from
391 * a block device.
392 */
393void blk_integrity_unregister(struct gendisk *disk)
394{
395	struct blk_integrity *bi = &disk->queue->integrity;
396
397	if (!bi->profile)
398		return;
399
400	/* ensure all bios are off the integrity workqueue */
401	blk_flush_integrity();
402	blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, disk->queue);
403	memset(bi, 0, sizeof(*bi));
404}
405EXPORT_SYMBOL(blk_integrity_unregister);
406