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/blkdev.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  */
blk_rq_count_integrity_sg(struct request_queue * q,struct bio * bio)27 int 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 {
45 new_segment:
46 			segments++;
47 			seg_size = iv.bv_len;
48 		}
49 
50 		prev = 1;
51 		ivprv = iv;
52 	}
53 
54 	return segments;
55 }
56 EXPORT_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  */
blk_rq_map_integrity_sg(struct request_queue * q,struct bio * bio,struct scatterlist * sglist)68 int 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 {
87 new_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 }
108 EXPORT_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  */
blk_integrity_compare(struct gendisk * gd1,struct gendisk * gd2)121 int 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 }
162 EXPORT_SYMBOL(blk_integrity_compare);
163 
blk_integrity_merge_rq(struct request_queue * q,struct request * req,struct request * next)164 bool 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 EXPORT_SYMBOL(blk_integrity_merge_rq);
187 
blk_integrity_merge_bio(struct request_queue * q,struct request * req,struct bio * bio)188 bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
189 			     struct bio *bio)
190 {
191 	int nr_integrity_segs;
192 	struct bio *next = bio->bi_next;
193 
194 	if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL)
195 		return true;
196 
197 	if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL)
198 		return false;
199 
200 	if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags)
201 		return false;
202 
203 	bio->bi_next = NULL;
204 	nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
205 	bio->bi_next = next;
206 
207 	if (req->nr_integrity_segments + nr_integrity_segs >
208 	    q->limits.max_integrity_segments)
209 		return false;
210 
211 	req->nr_integrity_segments += nr_integrity_segs;
212 
213 	return true;
214 }
215 EXPORT_SYMBOL(blk_integrity_merge_bio);
216 
217 struct integrity_sysfs_entry {
218 	struct attribute attr;
219 	ssize_t (*show)(struct blk_integrity *, char *);
220 	ssize_t (*store)(struct blk_integrity *, const char *, size_t);
221 };
222 
integrity_attr_show(struct kobject * kobj,struct attribute * attr,char * page)223 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
224 				   char *page)
225 {
226 	struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
227 	struct blk_integrity *bi = &disk->queue->integrity;
228 	struct integrity_sysfs_entry *entry =
229 		container_of(attr, struct integrity_sysfs_entry, attr);
230 
231 	return entry->show(bi, page);
232 }
233 
integrity_attr_store(struct kobject * kobj,struct attribute * attr,const char * page,size_t count)234 static ssize_t integrity_attr_store(struct kobject *kobj,
235 				    struct attribute *attr, const char *page,
236 				    size_t count)
237 {
238 	struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
239 	struct blk_integrity *bi = &disk->queue->integrity;
240 	struct integrity_sysfs_entry *entry =
241 		container_of(attr, struct integrity_sysfs_entry, attr);
242 	ssize_t ret = 0;
243 
244 	if (entry->store)
245 		ret = entry->store(bi, page, count);
246 
247 	return ret;
248 }
249 
integrity_format_show(struct blk_integrity * bi,char * page)250 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
251 {
252 	if (bi->profile && bi->profile->name)
253 		return sprintf(page, "%s\n", bi->profile->name);
254 	else
255 		return sprintf(page, "none\n");
256 }
257 
integrity_tag_size_show(struct blk_integrity * bi,char * page)258 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
259 {
260 	return sprintf(page, "%u\n", bi->tag_size);
261 }
262 
integrity_interval_show(struct blk_integrity * bi,char * page)263 static ssize_t integrity_interval_show(struct blk_integrity *bi, char *page)
264 {
265 	return sprintf(page, "%u\n",
266 		       bi->interval_exp ? 1 << bi->interval_exp : 0);
267 }
268 
integrity_verify_store(struct blk_integrity * bi,const char * page,size_t count)269 static ssize_t integrity_verify_store(struct blk_integrity *bi,
270 				      const char *page, size_t count)
271 {
272 	char *p = (char *) page;
273 	unsigned long val = simple_strtoul(p, &p, 10);
274 
275 	if (val)
276 		bi->flags |= BLK_INTEGRITY_VERIFY;
277 	else
278 		bi->flags &= ~BLK_INTEGRITY_VERIFY;
279 
280 	return count;
281 }
282 
integrity_verify_show(struct blk_integrity * bi,char * page)283 static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page)
284 {
285 	return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0);
286 }
287 
integrity_generate_store(struct blk_integrity * bi,const char * page,size_t count)288 static ssize_t integrity_generate_store(struct blk_integrity *bi,
289 					const char *page, size_t count)
290 {
291 	char *p = (char *) page;
292 	unsigned long val = simple_strtoul(p, &p, 10);
293 
294 	if (val)
295 		bi->flags |= BLK_INTEGRITY_GENERATE;
296 	else
297 		bi->flags &= ~BLK_INTEGRITY_GENERATE;
298 
299 	return count;
300 }
301 
integrity_generate_show(struct blk_integrity * bi,char * page)302 static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page)
303 {
304 	return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0);
305 }
306 
integrity_device_show(struct blk_integrity * bi,char * page)307 static ssize_t integrity_device_show(struct blk_integrity *bi, char *page)
308 {
309 	return sprintf(page, "%u\n",
310 		       (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0);
311 }
312 
313 static struct integrity_sysfs_entry integrity_format_entry = {
314 	.attr = { .name = "format", .mode = 0444 },
315 	.show = integrity_format_show,
316 };
317 
318 static struct integrity_sysfs_entry integrity_tag_size_entry = {
319 	.attr = { .name = "tag_size", .mode = 0444 },
320 	.show = integrity_tag_size_show,
321 };
322 
323 static struct integrity_sysfs_entry integrity_interval_entry = {
324 	.attr = { .name = "protection_interval_bytes", .mode = 0444 },
325 	.show = integrity_interval_show,
326 };
327 
328 static struct integrity_sysfs_entry integrity_verify_entry = {
329 	.attr = { .name = "read_verify", .mode = 0644 },
330 	.show = integrity_verify_show,
331 	.store = integrity_verify_store,
332 };
333 
334 static struct integrity_sysfs_entry integrity_generate_entry = {
335 	.attr = { .name = "write_generate", .mode = 0644 },
336 	.show = integrity_generate_show,
337 	.store = integrity_generate_store,
338 };
339 
340 static struct integrity_sysfs_entry integrity_device_entry = {
341 	.attr = { .name = "device_is_integrity_capable", .mode = 0444 },
342 	.show = integrity_device_show,
343 };
344 
345 static struct attribute *integrity_attrs[] = {
346 	&integrity_format_entry.attr,
347 	&integrity_tag_size_entry.attr,
348 	&integrity_interval_entry.attr,
349 	&integrity_verify_entry.attr,
350 	&integrity_generate_entry.attr,
351 	&integrity_device_entry.attr,
352 	NULL,
353 };
354 ATTRIBUTE_GROUPS(integrity);
355 
356 static const struct sysfs_ops integrity_ops = {
357 	.show	= &integrity_attr_show,
358 	.store	= &integrity_attr_store,
359 };
360 
361 static struct kobj_type integrity_ktype = {
362 	.default_groups = integrity_groups,
363 	.sysfs_ops	= &integrity_ops,
364 };
365 
blk_integrity_nop_fn(struct blk_integrity_iter * iter)366 static blk_status_t blk_integrity_nop_fn(struct blk_integrity_iter *iter)
367 {
368 	return BLK_STS_OK;
369 }
370 
blk_integrity_nop_prepare(struct request * rq)371 static void blk_integrity_nop_prepare(struct request *rq)
372 {
373 }
374 
blk_integrity_nop_complete(struct request * rq,unsigned int nr_bytes)375 static void blk_integrity_nop_complete(struct request *rq,
376 		unsigned int nr_bytes)
377 {
378 }
379 
380 static const struct blk_integrity_profile nop_profile = {
381 	.name = "nop",
382 	.generate_fn = blk_integrity_nop_fn,
383 	.verify_fn = blk_integrity_nop_fn,
384 	.prepare_fn = blk_integrity_nop_prepare,
385 	.complete_fn = blk_integrity_nop_complete,
386 };
387 
388 /**
389  * blk_integrity_register - Register a gendisk as being integrity-capable
390  * @disk:	struct gendisk pointer to make integrity-aware
391  * @template:	block integrity profile to register
392  *
393  * Description: When a device needs to advertise itself as being able to
394  * send/receive integrity metadata it must use this function to register
395  * the capability with the block layer. The template is a blk_integrity
396  * struct with values appropriate for the underlying hardware. See
397  * Documentation/block/data-integrity.rst.
398  */
blk_integrity_register(struct gendisk * disk,struct blk_integrity * template)399 void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
400 {
401 	struct blk_integrity *bi = &disk->queue->integrity;
402 
403 	bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
404 		template->flags;
405 	bi->interval_exp = template->interval_exp ? :
406 		ilog2(queue_logical_block_size(disk->queue));
407 	bi->profile = template->profile ? template->profile : &nop_profile;
408 	bi->tuple_size = template->tuple_size;
409 	bi->tag_size = template->tag_size;
410 
411 	disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
412 }
413 EXPORT_SYMBOL(blk_integrity_register);
414 
415 /**
416  * blk_integrity_unregister - Unregister block integrity profile
417  * @disk:	disk whose integrity profile to unregister
418  *
419  * Description: This function unregisters the integrity capability from
420  * a block device.
421  */
blk_integrity_unregister(struct gendisk * disk)422 void blk_integrity_unregister(struct gendisk *disk)
423 {
424 	disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
425 	memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
426 }
427 EXPORT_SYMBOL(blk_integrity_unregister);
428 
blk_integrity_add(struct gendisk * disk)429 void blk_integrity_add(struct gendisk *disk)
430 {
431 	if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
432 				 &disk_to_dev(disk)->kobj, "%s", "integrity"))
433 		return;
434 
435 	kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
436 }
437 
blk_integrity_del(struct gendisk * disk)438 void blk_integrity_del(struct gendisk *disk)
439 {
440 	kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE);
441 	kobject_del(&disk->integrity_kobj);
442 	kobject_put(&disk->integrity_kobj);
443 }
444