xref: /openbmc/linux/block/bio-integrity.c (revision 415d8324)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bio-integrity.c - bio data integrity extensions
4  *
5  * Copyright (C) 2007, 2008, 2009 Oracle Corporation
6  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
7  */
8 
9 #include <linux/blk-integrity.h>
10 #include <linux/mempool.h>
11 #include <linux/export.h>
12 #include <linux/bio.h>
13 #include <linux/workqueue.h>
14 #include <linux/slab.h>
15 #include "blk.h"
16 
17 static struct kmem_cache *bip_slab;
18 static struct workqueue_struct *kintegrityd_wq;
19 
20 void blk_flush_integrity(void)
21 {
22 	flush_workqueue(kintegrityd_wq);
23 }
24 
25 static void __bio_integrity_free(struct bio_set *bs,
26 				 struct bio_integrity_payload *bip)
27 {
28 	if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
29 		if (bip->bip_vec)
30 			bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
31 				  bip->bip_max_vcnt);
32 		mempool_free(bip, &bs->bio_integrity_pool);
33 	} else {
34 		kfree(bip);
35 	}
36 }
37 
38 /**
39  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
40  * @bio:	bio to attach integrity metadata to
41  * @gfp_mask:	Memory allocation mask
42  * @nr_vecs:	Number of integrity metadata scatter-gather elements
43  *
44  * Description: This function prepares a bio for attaching integrity
45  * metadata.  nr_vecs specifies the maximum number of pages containing
46  * integrity metadata that can be attached.
47  */
48 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
49 						  gfp_t gfp_mask,
50 						  unsigned int nr_vecs)
51 {
52 	struct bio_integrity_payload *bip;
53 	struct bio_set *bs = bio->bi_pool;
54 	unsigned inline_vecs;
55 
56 	if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
57 		return ERR_PTR(-EOPNOTSUPP);
58 
59 	if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
60 		bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
61 		inline_vecs = nr_vecs;
62 	} else {
63 		bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
64 		inline_vecs = BIO_INLINE_VECS;
65 	}
66 
67 	if (unlikely(!bip))
68 		return ERR_PTR(-ENOMEM);
69 
70 	memset(bip, 0, sizeof(*bip));
71 
72 	if (nr_vecs > inline_vecs) {
73 		bip->bip_max_vcnt = nr_vecs;
74 		bip->bip_vec = bvec_alloc(&bs->bvec_integrity_pool,
75 					  &bip->bip_max_vcnt, gfp_mask);
76 		if (!bip->bip_vec)
77 			goto err;
78 	} else {
79 		bip->bip_vec = bip->bip_inline_vecs;
80 		bip->bip_max_vcnt = inline_vecs;
81 	}
82 
83 	bip->bip_bio = bio;
84 	bio->bi_integrity = bip;
85 	bio->bi_opf |= REQ_INTEGRITY;
86 
87 	return bip;
88 err:
89 	__bio_integrity_free(bs, bip);
90 	return ERR_PTR(-ENOMEM);
91 }
92 EXPORT_SYMBOL(bio_integrity_alloc);
93 
94 /**
95  * bio_integrity_free - Free bio integrity payload
96  * @bio:	bio containing bip to be freed
97  *
98  * Description: Used to free the integrity portion of a bio. Usually
99  * called from bio_free().
100  */
101 void bio_integrity_free(struct bio *bio)
102 {
103 	struct bio_integrity_payload *bip = bio_integrity(bio);
104 	struct bio_set *bs = bio->bi_pool;
105 
106 	if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
107 		kfree(bvec_virt(bip->bip_vec));
108 
109 	__bio_integrity_free(bs, bip);
110 	bio->bi_integrity = NULL;
111 	bio->bi_opf &= ~REQ_INTEGRITY;
112 }
113 
114 /**
115  * bio_integrity_add_page - Attach integrity metadata
116  * @bio:	bio to update
117  * @page:	page containing integrity metadata
118  * @len:	number of bytes of integrity metadata in page
119  * @offset:	start offset within page
120  *
121  * Description: Attach a page containing integrity metadata to bio.
122  */
123 int bio_integrity_add_page(struct bio *bio, struct page *page,
124 			   unsigned int len, unsigned int offset)
125 {
126 	struct bio_integrity_payload *bip = bio_integrity(bio);
127 	struct bio_vec *iv;
128 
129 	if (bip->bip_vcnt >= bip->bip_max_vcnt) {
130 		printk(KERN_ERR "%s: bip_vec full\n", __func__);
131 		return 0;
132 	}
133 
134 	iv = bip->bip_vec + bip->bip_vcnt;
135 
136 	if (bip->bip_vcnt &&
137 	    bvec_gap_to_prev(&bdev_get_queue(bio->bi_bdev)->limits,
138 			     &bip->bip_vec[bip->bip_vcnt - 1], offset))
139 		return 0;
140 
141 	iv->bv_page = page;
142 	iv->bv_len = len;
143 	iv->bv_offset = offset;
144 	bip->bip_vcnt++;
145 
146 	return len;
147 }
148 EXPORT_SYMBOL(bio_integrity_add_page);
149 
150 /**
151  * bio_integrity_process - Process integrity metadata for a bio
152  * @bio:	bio to generate/verify integrity metadata for
153  * @proc_iter:  iterator to process
154  * @proc_fn:	Pointer to the relevant processing function
155  */
156 static blk_status_t bio_integrity_process(struct bio *bio,
157 		struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
158 {
159 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
160 	struct blk_integrity_iter iter;
161 	struct bvec_iter bviter;
162 	struct bio_vec bv;
163 	struct bio_integrity_payload *bip = bio_integrity(bio);
164 	blk_status_t ret = BLK_STS_OK;
165 
166 	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
167 	iter.interval = 1 << bi->interval_exp;
168 	iter.tuple_size = bi->tuple_size;
169 	iter.seed = proc_iter->bi_sector;
170 	iter.prot_buf = bvec_virt(bip->bip_vec);
171 
172 	__bio_for_each_segment(bv, bio, bviter, *proc_iter) {
173 		void *kaddr = bvec_kmap_local(&bv);
174 
175 		iter.data_buf = kaddr;
176 		iter.data_size = bv.bv_len;
177 		ret = proc_fn(&iter);
178 		kunmap_local(kaddr);
179 
180 		if (ret)
181 			break;
182 
183 	}
184 	return ret;
185 }
186 
187 /**
188  * bio_integrity_prep - Prepare bio for integrity I/O
189  * @bio:	bio to prepare
190  *
191  * Description:  Checks if the bio already has an integrity payload attached.
192  * If it does, the payload has been generated by another kernel subsystem,
193  * and we just pass it through. Otherwise allocates integrity payload.
194  * The bio must have data direction, target device and start sector set priot
195  * to calling.  In the WRITE case, integrity metadata will be generated using
196  * the block device's integrity function.  In the READ case, the buffer
197  * will be prepared for DMA and a suitable end_io handler set up.
198  */
199 bool bio_integrity_prep(struct bio *bio)
200 {
201 	struct bio_integrity_payload *bip;
202 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
203 	void *buf;
204 	unsigned long start, end;
205 	unsigned int len, nr_pages;
206 	unsigned int bytes, offset, i;
207 	unsigned int intervals;
208 	blk_status_t status;
209 
210 	if (!bi)
211 		return true;
212 
213 	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
214 		return true;
215 
216 	if (!bio_sectors(bio))
217 		return true;
218 
219 	/* Already protected? */
220 	if (bio_integrity(bio))
221 		return true;
222 
223 	if (bio_data_dir(bio) == READ) {
224 		if (!bi->profile->verify_fn ||
225 		    !(bi->flags & BLK_INTEGRITY_VERIFY))
226 			return true;
227 	} else {
228 		if (!bi->profile->generate_fn ||
229 		    !(bi->flags & BLK_INTEGRITY_GENERATE))
230 			return true;
231 	}
232 	intervals = bio_integrity_intervals(bi, bio_sectors(bio));
233 
234 	/* Allocate kernel buffer for protection data */
235 	len = intervals * bi->tuple_size;
236 	buf = kmalloc(len, GFP_NOIO);
237 	status = BLK_STS_RESOURCE;
238 	if (unlikely(buf == NULL)) {
239 		printk(KERN_ERR "could not allocate integrity buffer\n");
240 		goto err_end_io;
241 	}
242 
243 	end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
244 	start = ((unsigned long) buf) >> PAGE_SHIFT;
245 	nr_pages = end - start;
246 
247 	/* Allocate bio integrity payload and integrity vectors */
248 	bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
249 	if (IS_ERR(bip)) {
250 		printk(KERN_ERR "could not allocate data integrity bioset\n");
251 		kfree(buf);
252 		status = BLK_STS_RESOURCE;
253 		goto err_end_io;
254 	}
255 
256 	bip->bip_flags |= BIP_BLOCK_INTEGRITY;
257 	bip->bip_iter.bi_size = len;
258 	bip_set_seed(bip, bio->bi_iter.bi_sector);
259 
260 	if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
261 		bip->bip_flags |= BIP_IP_CHECKSUM;
262 
263 	/* Map it */
264 	offset = offset_in_page(buf);
265 	for (i = 0 ; i < nr_pages ; i++) {
266 		int ret;
267 		bytes = PAGE_SIZE - offset;
268 
269 		if (len <= 0)
270 			break;
271 
272 		if (bytes > len)
273 			bytes = len;
274 
275 		ret = bio_integrity_add_page(bio, virt_to_page(buf),
276 					     bytes, offset);
277 
278 		if (ret == 0) {
279 			printk(KERN_ERR "could not attach integrity payload\n");
280 			status = BLK_STS_RESOURCE;
281 			goto err_end_io;
282 		}
283 
284 		if (ret < bytes)
285 			break;
286 
287 		buf += bytes;
288 		len -= bytes;
289 		offset = 0;
290 	}
291 
292 	/* Auto-generate integrity metadata if this is a write */
293 	if (bio_data_dir(bio) == WRITE) {
294 		bio_integrity_process(bio, &bio->bi_iter,
295 				      bi->profile->generate_fn);
296 	} else {
297 		bip->bio_iter = bio->bi_iter;
298 	}
299 	return true;
300 
301 err_end_io:
302 	bio->bi_status = status;
303 	bio_endio(bio);
304 	return false;
305 
306 }
307 EXPORT_SYMBOL(bio_integrity_prep);
308 
309 /**
310  * bio_integrity_verify_fn - Integrity I/O completion worker
311  * @work:	Work struct stored in bio to be verified
312  *
313  * Description: This workqueue function is called to complete a READ
314  * request.  The function verifies the transferred integrity metadata
315  * and then calls the original bio end_io function.
316  */
317 static void bio_integrity_verify_fn(struct work_struct *work)
318 {
319 	struct bio_integrity_payload *bip =
320 		container_of(work, struct bio_integrity_payload, bip_work);
321 	struct bio *bio = bip->bip_bio;
322 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
323 
324 	/*
325 	 * At the moment verify is called bio's iterator was advanced
326 	 * during split and completion, we need to rewind iterator to
327 	 * it's original position.
328 	 */
329 	bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
330 						bi->profile->verify_fn);
331 	bio_integrity_free(bio);
332 	bio_endio(bio);
333 }
334 
335 /**
336  * __bio_integrity_endio - Integrity I/O completion function
337  * @bio:	Protected bio
338  *
339  * Description: Completion for integrity I/O
340  *
341  * Normally I/O completion is done in interrupt context.  However,
342  * verifying I/O integrity is a time-consuming task which must be run
343  * in process context.	This function postpones completion
344  * accordingly.
345  */
346 bool __bio_integrity_endio(struct bio *bio)
347 {
348 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
349 	struct bio_integrity_payload *bip = bio_integrity(bio);
350 
351 	if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
352 	    (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
353 		INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
354 		queue_work(kintegrityd_wq, &bip->bip_work);
355 		return false;
356 	}
357 
358 	bio_integrity_free(bio);
359 	return true;
360 }
361 
362 /**
363  * bio_integrity_advance - Advance integrity vector
364  * @bio:	bio whose integrity vector to update
365  * @bytes_done:	number of data bytes that have been completed
366  *
367  * Description: This function calculates how many integrity bytes the
368  * number of completed data bytes correspond to and advances the
369  * integrity vector accordingly.
370  */
371 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
372 {
373 	struct bio_integrity_payload *bip = bio_integrity(bio);
374 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
375 	unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
376 
377 	bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
378 	bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
379 }
380 
381 /**
382  * bio_integrity_trim - Trim integrity vector
383  * @bio:	bio whose integrity vector to update
384  *
385  * Description: Used to trim the integrity vector in a cloned bio.
386  */
387 void bio_integrity_trim(struct bio *bio)
388 {
389 	struct bio_integrity_payload *bip = bio_integrity(bio);
390 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
391 
392 	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
393 }
394 EXPORT_SYMBOL(bio_integrity_trim);
395 
396 /**
397  * bio_integrity_clone - Callback for cloning bios with integrity metadata
398  * @bio:	New bio
399  * @bio_src:	Original bio
400  * @gfp_mask:	Memory allocation mask
401  *
402  * Description:	Called to allocate a bip when cloning a bio
403  */
404 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
405 			gfp_t gfp_mask)
406 {
407 	struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
408 	struct bio_integrity_payload *bip;
409 
410 	BUG_ON(bip_src == NULL);
411 
412 	bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
413 	if (IS_ERR(bip))
414 		return PTR_ERR(bip);
415 
416 	memcpy(bip->bip_vec, bip_src->bip_vec,
417 	       bip_src->bip_vcnt * sizeof(struct bio_vec));
418 
419 	bip->bip_vcnt = bip_src->bip_vcnt;
420 	bip->bip_iter = bip_src->bip_iter;
421 
422 	return 0;
423 }
424 
425 int bioset_integrity_create(struct bio_set *bs, int pool_size)
426 {
427 	if (mempool_initialized(&bs->bio_integrity_pool))
428 		return 0;
429 
430 	if (mempool_init_slab_pool(&bs->bio_integrity_pool,
431 				   pool_size, bip_slab))
432 		return -1;
433 
434 	if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
435 		mempool_exit(&bs->bio_integrity_pool);
436 		return -1;
437 	}
438 
439 	return 0;
440 }
441 EXPORT_SYMBOL(bioset_integrity_create);
442 
443 void bioset_integrity_free(struct bio_set *bs)
444 {
445 	mempool_exit(&bs->bio_integrity_pool);
446 	mempool_exit(&bs->bvec_integrity_pool);
447 }
448 
449 void __init bio_integrity_init(void)
450 {
451 	/*
452 	 * kintegrityd won't block much but may burn a lot of CPU cycles.
453 	 * Make it highpri CPU intensive wq with max concurrency of 1.
454 	 */
455 	kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
456 					 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
457 	if (!kintegrityd_wq)
458 		panic("Failed to create kintegrityd\n");
459 
460 	bip_slab = kmem_cache_create("bio_integrity_payload",
461 				     sizeof(struct bio_integrity_payload) +
462 				     sizeof(struct bio_vec) * BIO_INLINE_VECS,
463 				     0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
464 }
465