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Linux/block/bio-integrity.c

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  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 
 19 static struct kmem_cache *bip_slab;
 20 static struct workqueue_struct *kintegrityd_wq;
 21 
 22 void blk_flush_integrity(void)
 23 {
 24         flush_workqueue(kintegrityd_wq);
 25 }
 26 
 27 static 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  */
 50 struct 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;
 93 err:
 94         __bio_integrity_free(bs, bip);
 95         return ERR_PTR(-ENOMEM);
 96 }
 97 EXPORT_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  */
106 void 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  */
129 int 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 }
154 EXPORT_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  */
162 static 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  */
208 bool 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 
311 err_end_io:
312         bio->bi_status = status;
313         bio_endio(bio);
314         return false;
315 
316 }
317 EXPORT_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  */
327 static 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  */
356 bool __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  */
381 void 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 += 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  */
397 void 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 }
404 EXPORT_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  */
414 int 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 
432         return 0;
433 }
434 EXPORT_SYMBOL(bio_integrity_clone);
435 
436 int bioset_integrity_create(struct bio_set *bs, int pool_size)
437 {
438         if (mempool_initialized(&bs->bio_integrity_pool))
439                 return 0;
440 
441         if (mempool_init_slab_pool(&bs->bio_integrity_pool,
442                                    pool_size, bip_slab))
443                 return -1;
444 
445         if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
446                 mempool_exit(&bs->bio_integrity_pool);
447                 return -1;
448         }
449 
450         return 0;
451 }
452 EXPORT_SYMBOL(bioset_integrity_create);
453 
454 void bioset_integrity_free(struct bio_set *bs)
455 {
456         mempool_exit(&bs->bio_integrity_pool);
457         mempool_exit(&bs->bvec_integrity_pool);
458 }
459 
460 void __init bio_integrity_init(void)
461 {
462         /*
463          * kintegrityd won't block much but may burn a lot of CPU cycles.
464          * Make it highpri CPU intensive wq with max concurrency of 1.
465          */
466         kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
467                                          WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
468         if (!kintegrityd_wq)
469                 panic("Failed to create kintegrityd\n");
470 
471         bip_slab = kmem_cache_create("bio_integrity_payload",
472                                      sizeof(struct bio_integrity_payload) +
473                                      sizeof(struct bio_vec) * BIP_INLINE_VECS,
474                                      0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
475 }
476 

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