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/blkdev.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#define BIP_INLINE_VECS	4
18
19static struct kmem_cache *bip_slab;
20static struct workqueue_struct *kintegrityd_wq;
21
22void blk_flush_integrity(void)
23{
24	flush_workqueue(kintegrityd_wq);
25}
26
27static void __bio_integrity_free(struct bio_set *bs,
28				 struct bio_integrity_payload *bip)
29{
30	if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
31		if (bip->bip_vec)
32			bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
33				  bip->bip_slab);
34		mempool_free(bip, &bs->bio_integrity_pool);
35	} else {
36		kfree(bip);
37	}
38}
39
40/**
41 * bio_integrity_alloc - Allocate integrity payload and attach it to bio
42 * @bio:	bio to attach integrity metadata to
43 * @gfp_mask:	Memory allocation mask
44 * @nr_vecs:	Number of integrity metadata scatter-gather elements
45 *
46 * Description: This function prepares a bio for attaching integrity
47 * metadata.  nr_vecs specifies the maximum number of pages containing
48 * integrity metadata that can be attached.
49 */
50struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
51						  gfp_t gfp_mask,
52						  unsigned int nr_vecs)
53{
54	struct bio_integrity_payload *bip;
55	struct bio_set *bs = bio->bi_pool;
56	unsigned inline_vecs;
57
58	if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
59		return ERR_PTR(-EOPNOTSUPP);
60
61	if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
62		bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
63		inline_vecs = nr_vecs;
64	} else {
65		bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
66		inline_vecs = BIP_INLINE_VECS;
67	}
68
69	if (unlikely(!bip))
70		return ERR_PTR(-ENOMEM);
71
72	memset(bip, 0, sizeof(*bip));
73
74	if (nr_vecs > inline_vecs) {
75		unsigned long idx = 0;
76
77		bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
78					  &bs->bvec_integrity_pool);
79		if (!bip->bip_vec)
80			goto err;
81		bip->bip_max_vcnt = bvec_nr_vecs(idx);
82		bip->bip_slab = idx;
83	} else {
84		bip->bip_vec = bip->bip_inline_vecs;
85		bip->bip_max_vcnt = inline_vecs;
86	}
87
88	bip->bip_bio = bio;
89	bio->bi_integrity = bip;
90	bio->bi_opf |= REQ_INTEGRITY;
91
92	return bip;
93err:
94	__bio_integrity_free(bs, bip);
95	return ERR_PTR(-ENOMEM);
96}
97EXPORT_SYMBOL(bio_integrity_alloc);
98
99/**
100 * bio_integrity_free - Free bio integrity payload
101 * @bio:	bio containing bip to be freed
102 *
103 * Description: Used to free the integrity portion of a bio. Usually
104 * called from bio_free().
105 */
106void bio_integrity_free(struct bio *bio)
107{
108	struct bio_integrity_payload *bip = bio_integrity(bio);
109	struct bio_set *bs = bio->bi_pool;
110
111	if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
112		kfree(page_address(bip->bip_vec->bv_page) +
113		      bip->bip_vec->bv_offset);
114
115	__bio_integrity_free(bs, bip);
116	bio->bi_integrity = NULL;
117	bio->bi_opf &= ~REQ_INTEGRITY;
118}
119
120/**
121 * bio_integrity_add_page - Attach integrity metadata
122 * @bio:	bio to update
123 * @page:	page containing integrity metadata
124 * @len:	number of bytes of integrity metadata in page
125 * @offset:	start offset within page
126 *
127 * Description: Attach a page containing integrity metadata to bio.
128 */
129int bio_integrity_add_page(struct bio *bio, struct page *page,
130			   unsigned int len, unsigned int offset)
131{
132	struct bio_integrity_payload *bip = bio_integrity(bio);
133	struct bio_vec *iv;
134
135	if (bip->bip_vcnt >= bip->bip_max_vcnt) {
136		printk(KERN_ERR "%s: bip_vec full\n", __func__);
137		return 0;
138	}
139
140	iv = bip->bip_vec + bip->bip_vcnt;
141
142	if (bip->bip_vcnt &&
143	    bvec_gap_to_prev(bio->bi_disk->queue,
144			     &bip->bip_vec[bip->bip_vcnt - 1], offset))
145		return 0;
146
147	iv->bv_page = page;
148	iv->bv_len = len;
149	iv->bv_offset = offset;
150	bip->bip_vcnt++;
151
152	return len;
153}
154EXPORT_SYMBOL(bio_integrity_add_page);
155
156/**
157 * bio_integrity_process - Process integrity metadata for a bio
158 * @bio:	bio to generate/verify integrity metadata for
159 * @proc_iter:  iterator to process
160 * @proc_fn:	Pointer to the relevant processing function
161 */
162static blk_status_t bio_integrity_process(struct bio *bio,
163		struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
164{
165	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
166	struct blk_integrity_iter iter;
167	struct bvec_iter bviter;
168	struct bio_vec bv;
169	struct bio_integrity_payload *bip = bio_integrity(bio);
170	blk_status_t ret = BLK_STS_OK;
171	void *prot_buf = page_address(bip->bip_vec->bv_page) +
172		bip->bip_vec->bv_offset;
173
174	iter.disk_name = bio->bi_disk->disk_name;
175	iter.interval = 1 << bi->interval_exp;
176	iter.seed = proc_iter->bi_sector;
177	iter.prot_buf = prot_buf;
178
179	__bio_for_each_segment(bv, bio, bviter, *proc_iter) {
180		void *kaddr = kmap_atomic(bv.bv_page);
181
182		iter.data_buf = kaddr + bv.bv_offset;
183		iter.data_size = bv.bv_len;
184
185		ret = proc_fn(&iter);
186		if (ret) {
187			kunmap_atomic(kaddr);
188			return ret;
189		}
190
191		kunmap_atomic(kaddr);
192	}
193	return ret;
194}
195
196/**
197 * bio_integrity_prep - Prepare bio for integrity I/O
198 * @bio:	bio to prepare
199 *
200 * Description:  Checks if the bio already has an integrity payload attached.
201 * If it does, the payload has been generated by another kernel subsystem,
202 * and we just pass it through. Otherwise allocates integrity payload.
203 * The bio must have data direction, target device and start sector set priot
204 * to calling.  In the WRITE case, integrity metadata will be generated using
205 * the block device's integrity function.  In the READ case, the buffer
206 * will be prepared for DMA and a suitable end_io handler set up.
207 */
208bool bio_integrity_prep(struct bio *bio)
209{
210	struct bio_integrity_payload *bip;
211	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
212	struct request_queue *q = bio->bi_disk->queue;
213	void *buf;
214	unsigned long start, end;
215	unsigned int len, nr_pages;
216	unsigned int bytes, offset, i;
217	unsigned int intervals;
218	blk_status_t status;
219
220	if (!bi)
221		return true;
222
223	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
224		return true;
225
226	if (!bio_sectors(bio))
227		return true;
228
229	/* Already protected? */
230	if (bio_integrity(bio))
231		return true;
232
233	if (bio_data_dir(bio) == READ) {
234		if (!bi->profile->verify_fn ||
235		    !(bi->flags & BLK_INTEGRITY_VERIFY))
236			return true;
237	} else {
238		if (!bi->profile->generate_fn ||
239		    !(bi->flags & BLK_INTEGRITY_GENERATE))
240			return true;
241	}
242	intervals = bio_integrity_intervals(bi, bio_sectors(bio));
243
244	/* Allocate kernel buffer for protection data */
245	len = intervals * bi->tuple_size;
246	buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
247	status = BLK_STS_RESOURCE;
248	if (unlikely(buf == NULL)) {
249		printk(KERN_ERR "could not allocate integrity buffer\n");
250		goto err_end_io;
251	}
252
253	end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
254	start = ((unsigned long) buf) >> PAGE_SHIFT;
255	nr_pages = end - start;
256
257	/* Allocate bio integrity payload and integrity vectors */
258	bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
259	if (IS_ERR(bip)) {
260		printk(KERN_ERR "could not allocate data integrity bioset\n");
261		kfree(buf);
262		status = BLK_STS_RESOURCE;
263		goto err_end_io;
264	}
265
266	bip->bip_flags |= BIP_BLOCK_INTEGRITY;
267	bip->bip_iter.bi_size = len;
268	bip_set_seed(bip, bio->bi_iter.bi_sector);
269
270	if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
271		bip->bip_flags |= BIP_IP_CHECKSUM;
272
273	/* Map it */
274	offset = offset_in_page(buf);
275	for (i = 0 ; i < nr_pages ; i++) {
276		int ret;
277		bytes = PAGE_SIZE - offset;
278
279		if (len <= 0)
280			break;
281
282		if (bytes > len)
283			bytes = len;
284
285		ret = bio_integrity_add_page(bio, virt_to_page(buf),
286					     bytes, offset);
287
288		if (ret == 0) {
289			printk(KERN_ERR "could not attach integrity payload\n");
290			status = BLK_STS_RESOURCE;
291			goto err_end_io;
292		}
293
294		if (ret < bytes)
295			break;
296
297		buf += bytes;
298		len -= bytes;
299		offset = 0;
300	}
301
302	/* Auto-generate integrity metadata if this is a write */
303	if (bio_data_dir(bio) == WRITE) {
304		bio_integrity_process(bio, &bio->bi_iter,
305				      bi->profile->generate_fn);
306	} else {
307		bip->bio_iter = bio->bi_iter;
308	}
309	return true;
310
311err_end_io:
312	bio->bi_status = status;
313	bio_endio(bio);
314	return false;
315
316}
317EXPORT_SYMBOL(bio_integrity_prep);
318
319/**
320 * bio_integrity_verify_fn - Integrity I/O completion worker
321 * @work:	Work struct stored in bio to be verified
322 *
323 * Description: This workqueue function is called to complete a READ
324 * request.  The function verifies the transferred integrity metadata
325 * and then calls the original bio end_io function.
326 */
327static void bio_integrity_verify_fn(struct work_struct *work)
328{
329	struct bio_integrity_payload *bip =
330		container_of(work, struct bio_integrity_payload, bip_work);
331	struct bio *bio = bip->bip_bio;
332	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
333
334	/*
335	 * At the moment verify is called bio's iterator was advanced
336	 * during split and completion, we need to rewind iterator to
337	 * it's original position.
338	 */
339	bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
340						bi->profile->verify_fn);
341	bio_integrity_free(bio);
342	bio_endio(bio);
343}
344
345/**
346 * __bio_integrity_endio - Integrity I/O completion function
347 * @bio:	Protected bio
348 *
349 * Description: Completion for integrity I/O
350 *
351 * Normally I/O completion is done in interrupt context.  However,
352 * verifying I/O integrity is a time-consuming task which must be run
353 * in process context.	This function postpones completion
354 * accordingly.
355 */
356bool __bio_integrity_endio(struct bio *bio)
357{
358	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
359	struct bio_integrity_payload *bip = bio_integrity(bio);
360
361	if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
362	    (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
363		INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
364		queue_work(kintegrityd_wq, &bip->bip_work);
365		return false;
366	}
367
368	bio_integrity_free(bio);
369	return true;
370}
371
372/**
373 * bio_integrity_advance - Advance integrity vector
374 * @bio:	bio whose integrity vector to update
375 * @bytes_done:	number of data bytes that have been completed
376 *
377 * Description: This function calculates how many integrity bytes the
378 * number of completed data bytes correspond to and advances the
379 * integrity vector accordingly.
380 */
381void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
382{
383	struct bio_integrity_payload *bip = bio_integrity(bio);
384	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
385	unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
386
387	bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
388	bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
389}
390
391/**
392 * bio_integrity_trim - Trim integrity vector
393 * @bio:	bio whose integrity vector to update
394 *
395 * Description: Used to trim the integrity vector in a cloned bio.
396 */
397void bio_integrity_trim(struct bio *bio)
398{
399	struct bio_integrity_payload *bip = bio_integrity(bio);
400	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
401
402	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
403}
404EXPORT_SYMBOL(bio_integrity_trim);
405
406/**
407 * bio_integrity_clone - Callback for cloning bios with integrity metadata
408 * @bio:	New bio
409 * @bio_src:	Original bio
410 * @gfp_mask:	Memory allocation mask
411 *
412 * Description:	Called to allocate a bip when cloning a bio
413 */
414int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
415			gfp_t gfp_mask)
416{
417	struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
418	struct bio_integrity_payload *bip;
419
420	BUG_ON(bip_src == NULL);
421
422	bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
423	if (IS_ERR(bip))
424		return PTR_ERR(bip);
425
426	memcpy(bip->bip_vec, bip_src->bip_vec,
427	       bip_src->bip_vcnt * sizeof(struct bio_vec));
428
429	bip->bip_vcnt = bip_src->bip_vcnt;
430	bip->bip_iter = bip_src->bip_iter;
431	bip->bip_flags = bip_src->bip_flags & ~BIP_BLOCK_INTEGRITY;
432
433	return 0;
434}
435EXPORT_SYMBOL(bio_integrity_clone);
436
437int bioset_integrity_create(struct bio_set *bs, int pool_size)
438{
439	if (mempool_initialized(&bs->bio_integrity_pool))
440		return 0;
441
442	if (mempool_init_slab_pool(&bs->bio_integrity_pool,
443				   pool_size, bip_slab))
444		return -1;
445
446	if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
447		mempool_exit(&bs->bio_integrity_pool);
448		return -1;
449	}
450
451	return 0;
452}
453EXPORT_SYMBOL(bioset_integrity_create);
454
455void bioset_integrity_free(struct bio_set *bs)
456{
457	mempool_exit(&bs->bio_integrity_pool);
458	mempool_exit(&bs->bvec_integrity_pool);
459}
460
461void __init bio_integrity_init(void)
462{
463	/*
464	 * kintegrityd won't block much but may burn a lot of CPU cycles.
465	 * Make it highpri CPU intensive wq with max concurrency of 1.
466	 */
467	kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
468					 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
469	if (!kintegrityd_wq)
470		panic("Failed to create kintegrityd\n");
471
472	bip_slab = kmem_cache_create("bio_integrity_payload",
473				     sizeof(struct bio_integrity_payload) +
474				     sizeof(struct bio_vec) * BIP_INLINE_VECS,
475				     0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
476}
477