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1/*
2 * sd_dif.c - SCSI Data Integrity Field
3 *
4 * Copyright (C) 2007, 2008 Oracle Corporation
5 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; see the file COPYING. If not, write to
18 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
19 * USA.
20 *
21 */
22
23#include <linux/blkdev.h>
24#include <linux/crc-t10dif.h>
25
26#include <scsi/scsi.h>
27#include <scsi/scsi_cmnd.h>
28#include <scsi/scsi_dbg.h>
29#include <scsi/scsi_device.h>
30#include <scsi/scsi_driver.h>
31#include <scsi/scsi_eh.h>
32#include <scsi/scsi_host.h>
33#include <scsi/scsi_ioctl.h>
34#include <scsi/scsicam.h>
35
36#include <net/checksum.h>
37
38#include "sd.h"
39
40typedef __u16 (csum_fn) (void *, unsigned int);
41
42static __u16 sd_dif_crc_fn(void *data, unsigned int len)
43{
44 return cpu_to_be16(crc_t10dif(data, len));
45}
46
47static __u16 sd_dif_ip_fn(void *data, unsigned int len)
48{
49 return ip_compute_csum(data, len);
50}
51
52/*
53 * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
54 * 16 bit app tag, 32 bit reference tag.
55 */
56static void sd_dif_type1_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
57{
58 void *buf = bix->data_buf;
59 struct sd_dif_tuple *sdt = bix->prot_buf;
60 sector_t sector = bix->sector;
61 unsigned int i;
62
63 for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
64 sdt->guard_tag = fn(buf, bix->sector_size);
65 sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
66 sdt->app_tag = 0;
67
68 buf += bix->sector_size;
69 sector++;
70 }
71}
72
73static void sd_dif_type1_generate_crc(struct blk_integrity_exchg *bix)
74{
75 sd_dif_type1_generate(bix, sd_dif_crc_fn);
76}
77
78static void sd_dif_type1_generate_ip(struct blk_integrity_exchg *bix)
79{
80 sd_dif_type1_generate(bix, sd_dif_ip_fn);
81}
82
83static int sd_dif_type1_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
84{
85 void *buf = bix->data_buf;
86 struct sd_dif_tuple *sdt = bix->prot_buf;
87 sector_t sector = bix->sector;
88 unsigned int i;
89 __u16 csum;
90
91 for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
92 /* Unwritten sectors */
93 if (sdt->app_tag == 0xffff)
94 return 0;
95
96 /* Bad ref tag received from disk */
97 if (sdt->ref_tag == 0xffffffff) {
98 printk(KERN_ERR
99 "%s: bad phys ref tag on sector %lu\n",
100 bix->disk_name, (unsigned long)sector);
101 return -EIO;
102 }
103
104 if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
105 printk(KERN_ERR
106 "%s: ref tag error on sector %lu (rcvd %u)\n",
107 bix->disk_name, (unsigned long)sector,
108 be32_to_cpu(sdt->ref_tag));
109 return -EIO;
110 }
111
112 csum = fn(buf, bix->sector_size);
113
114 if (sdt->guard_tag != csum) {
115 printk(KERN_ERR "%s: guard tag error on sector %lu " \
116 "(rcvd %04x, data %04x)\n", bix->disk_name,
117 (unsigned long)sector,
118 be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
119 return -EIO;
120 }
121
122 buf += bix->sector_size;
123 sector++;
124 }
125
126 return 0;
127}
128
129static int sd_dif_type1_verify_crc(struct blk_integrity_exchg *bix)
130{
131 return sd_dif_type1_verify(bix, sd_dif_crc_fn);
132}
133
134static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
135{
136 return sd_dif_type1_verify(bix, sd_dif_ip_fn);
137}
138
139/*
140 * Functions for interleaving and deinterleaving application tags
141 */
142static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors)
143{
144 struct sd_dif_tuple *sdt = prot;
145 u8 *tag = tag_buf;
146 unsigned int i, j;
147
148 for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
149 sdt->app_tag = tag[j] << 8 | tag[j+1];
150 BUG_ON(sdt->app_tag == 0xffff);
151 }
152}
153
154static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors)
155{
156 struct sd_dif_tuple *sdt = prot;
157 u8 *tag = tag_buf;
158 unsigned int i, j;
159
160 for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
161 tag[j] = (sdt->app_tag & 0xff00) >> 8;
162 tag[j+1] = sdt->app_tag & 0xff;
163 }
164}
165
166static struct blk_integrity dif_type1_integrity_crc = {
167 .name = "T10-DIF-TYPE1-CRC",
168 .generate_fn = sd_dif_type1_generate_crc,
169 .verify_fn = sd_dif_type1_verify_crc,
170 .get_tag_fn = sd_dif_type1_get_tag,
171 .set_tag_fn = sd_dif_type1_set_tag,
172 .tuple_size = sizeof(struct sd_dif_tuple),
173 .tag_size = 0,
174};
175
176static struct blk_integrity dif_type1_integrity_ip = {
177 .name = "T10-DIF-TYPE1-IP",
178 .generate_fn = sd_dif_type1_generate_ip,
179 .verify_fn = sd_dif_type1_verify_ip,
180 .get_tag_fn = sd_dif_type1_get_tag,
181 .set_tag_fn = sd_dif_type1_set_tag,
182 .tuple_size = sizeof(struct sd_dif_tuple),
183 .tag_size = 0,
184};
185
186
187/*
188 * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque
189 * tag space.
190 */
191static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
192{
193 void *buf = bix->data_buf;
194 struct sd_dif_tuple *sdt = bix->prot_buf;
195 unsigned int i;
196
197 for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
198 sdt->guard_tag = fn(buf, bix->sector_size);
199 sdt->ref_tag = 0;
200 sdt->app_tag = 0;
201
202 buf += bix->sector_size;
203 }
204}
205
206static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix)
207{
208 sd_dif_type3_generate(bix, sd_dif_crc_fn);
209}
210
211static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix)
212{
213 sd_dif_type3_generate(bix, sd_dif_ip_fn);
214}
215
216static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
217{
218 void *buf = bix->data_buf;
219 struct sd_dif_tuple *sdt = bix->prot_buf;
220 sector_t sector = bix->sector;
221 unsigned int i;
222 __u16 csum;
223
224 for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
225 /* Unwritten sectors */
226 if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
227 return 0;
228
229 csum = fn(buf, bix->sector_size);
230
231 if (sdt->guard_tag != csum) {
232 printk(KERN_ERR "%s: guard tag error on sector %lu " \
233 "(rcvd %04x, data %04x)\n", bix->disk_name,
234 (unsigned long)sector,
235 be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
236 return -EIO;
237 }
238
239 buf += bix->sector_size;
240 sector++;
241 }
242
243 return 0;
244}
245
246static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix)
247{
248 return sd_dif_type3_verify(bix, sd_dif_crc_fn);
249}
250
251static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
252{
253 return sd_dif_type3_verify(bix, sd_dif_ip_fn);
254}
255
256static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors)
257{
258 struct sd_dif_tuple *sdt = prot;
259 u8 *tag = tag_buf;
260 unsigned int i, j;
261
262 for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) {
263 sdt->app_tag = tag[j] << 8 | tag[j+1];
264 sdt->ref_tag = tag[j+2] << 24 | tag[j+3] << 16 |
265 tag[j+4] << 8 | tag[j+5];
266 }
267}
268
269static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors)
270{
271 struct sd_dif_tuple *sdt = prot;
272 u8 *tag = tag_buf;
273 unsigned int i, j;
274
275 for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
276 tag[j] = (sdt->app_tag & 0xff00) >> 8;
277 tag[j+1] = sdt->app_tag & 0xff;
278 tag[j+2] = (sdt->ref_tag & 0xff000000) >> 24;
279 tag[j+3] = (sdt->ref_tag & 0xff0000) >> 16;
280 tag[j+4] = (sdt->ref_tag & 0xff00) >> 8;
281 tag[j+5] = sdt->ref_tag & 0xff;
282 BUG_ON(sdt->app_tag == 0xffff || sdt->ref_tag == 0xffffffff);
283 }
284}
285
286static struct blk_integrity dif_type3_integrity_crc = {
287 .name = "T10-DIF-TYPE3-CRC",
288 .generate_fn = sd_dif_type3_generate_crc,
289 .verify_fn = sd_dif_type3_verify_crc,
290 .get_tag_fn = sd_dif_type3_get_tag,
291 .set_tag_fn = sd_dif_type3_set_tag,
292 .tuple_size = sizeof(struct sd_dif_tuple),
293 .tag_size = 0,
294};
295
296static struct blk_integrity dif_type3_integrity_ip = {
297 .name = "T10-DIF-TYPE3-IP",
298 .generate_fn = sd_dif_type3_generate_ip,
299 .verify_fn = sd_dif_type3_verify_ip,
300 .get_tag_fn = sd_dif_type3_get_tag,
301 .set_tag_fn = sd_dif_type3_set_tag,
302 .tuple_size = sizeof(struct sd_dif_tuple),
303 .tag_size = 0,
304};
305
306/*
307 * Configure exchange of protection information between OS and HBA.
308 */
309void sd_dif_config_host(struct scsi_disk *sdkp)
310{
311 struct scsi_device *sdp = sdkp->device;
312 struct gendisk *disk = sdkp->disk;
313 u8 type = sdkp->protection_type;
314 int dif, dix;
315
316 dif = scsi_host_dif_capable(sdp->host, type);
317 dix = scsi_host_dix_capable(sdp->host, type);
318
319 if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
320 dif = 0; dix = 1;
321 }
322
323 if (!dix)
324 return;
325
326 /* Enable DMA of protection information */
327 if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
328 if (type == SD_DIF_TYPE3_PROTECTION)
329 blk_integrity_register(disk, &dif_type3_integrity_ip);
330 else
331 blk_integrity_register(disk, &dif_type1_integrity_ip);
332 else
333 if (type == SD_DIF_TYPE3_PROTECTION)
334 blk_integrity_register(disk, &dif_type3_integrity_crc);
335 else
336 blk_integrity_register(disk, &dif_type1_integrity_crc);
337
338 sd_printk(KERN_NOTICE, sdkp,
339 "Enabling DIX %s protection\n", disk->integrity->name);
340
341 /* Signal to block layer that we support sector tagging */
342 if (dif && type && sdkp->ATO) {
343 if (type == SD_DIF_TYPE3_PROTECTION)
344 disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
345 else
346 disk->integrity->tag_size = sizeof(u16);
347
348 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
349 disk->integrity->tag_size);
350 }
351}
352
353/*
354 * The virtual start sector is the one that was originally submitted
355 * by the block layer. Due to partitioning, MD/DM cloning, etc. the
356 * actual physical start sector is likely to be different. Remap
357 * protection information to match the physical LBA.
358 *
359 * From a protocol perspective there's a slight difference between
360 * Type 1 and 2. The latter uses 32-byte CDBs exclusively, and the
361 * reference tag is seeded in the CDB. This gives us the potential to
362 * avoid virt->phys remapping during write. However, at read time we
363 * don't know whether the virt sector is the same as when we wrote it
364 * (we could be reading from real disk as opposed to MD/DM device. So
365 * we always remap Type 2 making it identical to Type 1.
366 *
367 * Type 3 does not have a reference tag so no remapping is required.
368 */
369int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_sz)
370{
371 const int tuple_sz = sizeof(struct sd_dif_tuple);
372 struct bio *bio;
373 struct scsi_disk *sdkp;
374 struct sd_dif_tuple *sdt;
375 unsigned int i, j;
376 u32 phys, virt;
377
378 sdkp = rq->bio->bi_bdev->bd_disk->private_data;
379
380 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
381 return 0;
382
383 phys = hw_sector & 0xffffffff;
384
385 __rq_for_each_bio(bio, rq) {
386 struct bio_vec *iv;
387
388 /* Already remapped? */
389 if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
390 break;
391
392 virt = bio->bi_integrity->bip_sector & 0xffffffff;
393
394 bip_for_each_vec(iv, bio->bi_integrity, i) {
395 sdt = kmap_atomic(iv->bv_page, KM_USER0)
396 + iv->bv_offset;
397
398 for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
399
400 if (be32_to_cpu(sdt->ref_tag) != virt)
401 goto error;
402
403 sdt->ref_tag = cpu_to_be32(phys);
404 virt++;
405 phys++;
406 }
407
408 kunmap_atomic(sdt, KM_USER0);
409 }
410
411 bio->bi_flags |= BIO_MAPPED_INTEGRITY;
412 }
413
414 return 0;
415
416error:
417 kunmap_atomic(sdt, KM_USER0);
418 sd_printk(KERN_ERR, sdkp, "%s: virt %u, phys %u, ref %u, app %4x\n",
419 __func__, virt, phys, be32_to_cpu(sdt->ref_tag),
420 be16_to_cpu(sdt->app_tag));
421
422 return -EILSEQ;
423}
424
425/*
426 * Remap physical sector values in the reference tag to the virtual
427 * values expected by the block layer.
428 */
429void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
430{
431 const int tuple_sz = sizeof(struct sd_dif_tuple);
432 struct scsi_disk *sdkp;
433 struct bio *bio;
434 struct sd_dif_tuple *sdt;
435 unsigned int i, j, sectors, sector_sz;
436 u32 phys, virt;
437
438 sdkp = scsi_disk(scmd->request->rq_disk);
439
440 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
441 return;
442
443 sector_sz = scmd->device->sector_size;
444 sectors = good_bytes / sector_sz;
445
446 phys = blk_rq_pos(scmd->request) & 0xffffffff;
447 if (sector_sz == 4096)
448 phys >>= 3;
449
450 __rq_for_each_bio(bio, scmd->request) {
451 struct bio_vec *iv;
452
453 virt = bio->bi_integrity->bip_sector & 0xffffffff;
454
455 bip_for_each_vec(iv, bio->bi_integrity, i) {
456 sdt = kmap_atomic(iv->bv_page, KM_USER0)
457 + iv->bv_offset;
458
459 for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
460
461 if (sectors == 0) {
462 kunmap_atomic(sdt, KM_USER0);
463 return;
464 }
465
466 if (be32_to_cpu(sdt->ref_tag) != phys &&
467 sdt->app_tag != 0xffff)
468 sdt->ref_tag = 0xffffffff; /* Bad ref */
469 else
470 sdt->ref_tag = cpu_to_be32(virt);
471
472 virt++;
473 phys++;
474 sectors--;
475 }
476
477 kunmap_atomic(sdt, KM_USER0);
478 }
479 }
480}
481
1/*
2 * sd_dif.c - SCSI Data Integrity Field
3 *
4 * Copyright (C) 2007, 2008 Oracle Corporation
5 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; see the file COPYING. If not, write to
18 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
19 * USA.
20 *
21 */
22
23#include <linux/blkdev.h>
24#include <linux/t10-pi.h>
25
26#include <scsi/scsi.h>
27#include <scsi/scsi_cmnd.h>
28#include <scsi/scsi_dbg.h>
29#include <scsi/scsi_device.h>
30#include <scsi/scsi_driver.h>
31#include <scsi/scsi_eh.h>
32#include <scsi/scsi_host.h>
33#include <scsi/scsi_ioctl.h>
34#include <scsi/scsicam.h>
35
36#include "sd.h"
37
38/*
39 * Configure exchange of protection information between OS and HBA.
40 */
41void sd_dif_config_host(struct scsi_disk *sdkp)
42{
43 struct scsi_device *sdp = sdkp->device;
44 struct gendisk *disk = sdkp->disk;
45 u8 type = sdkp->protection_type;
46 struct blk_integrity bi;
47 int dif, dix;
48
49 dif = scsi_host_dif_capable(sdp->host, type);
50 dix = scsi_host_dix_capable(sdp->host, type);
51
52 if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
53 dif = 0; dix = 1;
54 }
55
56 if (!dix)
57 return;
58
59 memset(&bi, 0, sizeof(bi));
60
61 /* Enable DMA of protection information */
62 if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP) {
63 if (type == SD_DIF_TYPE3_PROTECTION)
64 bi.profile = &t10_pi_type3_ip;
65 else
66 bi.profile = &t10_pi_type1_ip;
67
68 bi.flags |= BLK_INTEGRITY_IP_CHECKSUM;
69 } else
70 if (type == SD_DIF_TYPE3_PROTECTION)
71 bi.profile = &t10_pi_type3_crc;
72 else
73 bi.profile = &t10_pi_type1_crc;
74
75 bi.tuple_size = sizeof(struct t10_pi_tuple);
76 sd_printk(KERN_NOTICE, sdkp,
77 "Enabling DIX %s protection\n", bi.profile->name);
78
79 if (dif && type) {
80 bi.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
81
82 if (!sdkp->ATO)
83 goto out;
84
85 if (type == SD_DIF_TYPE3_PROTECTION)
86 bi.tag_size = sizeof(u16) + sizeof(u32);
87 else
88 bi.tag_size = sizeof(u16);
89
90 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
91 bi.tag_size);
92 }
93
94out:
95 blk_integrity_register(disk, &bi);
96}
97
98/*
99 * The virtual start sector is the one that was originally submitted
100 * by the block layer. Due to partitioning, MD/DM cloning, etc. the
101 * actual physical start sector is likely to be different. Remap
102 * protection information to match the physical LBA.
103 *
104 * From a protocol perspective there's a slight difference between
105 * Type 1 and 2. The latter uses 32-byte CDBs exclusively, and the
106 * reference tag is seeded in the CDB. This gives us the potential to
107 * avoid virt->phys remapping during write. However, at read time we
108 * don't know whether the virt sector is the same as when we wrote it
109 * (we could be reading from real disk as opposed to MD/DM device. So
110 * we always remap Type 2 making it identical to Type 1.
111 *
112 * Type 3 does not have a reference tag so no remapping is required.
113 */
114void sd_dif_prepare(struct scsi_cmnd *scmd)
115{
116 const int tuple_sz = sizeof(struct t10_pi_tuple);
117 struct bio *bio;
118 struct scsi_disk *sdkp;
119 struct t10_pi_tuple *pi;
120 u32 phys, virt;
121
122 sdkp = scsi_disk(scmd->request->rq_disk);
123
124 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
125 return;
126
127 phys = scsi_prot_ref_tag(scmd);
128
129 __rq_for_each_bio(bio, scmd->request) {
130 struct bio_integrity_payload *bip = bio_integrity(bio);
131 struct bio_vec iv;
132 struct bvec_iter iter;
133 unsigned int j;
134
135 /* Already remapped? */
136 if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
137 break;
138
139 virt = bip_get_seed(bip) & 0xffffffff;
140
141 bip_for_each_vec(iv, bip, iter) {
142 pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
143
144 for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
145
146 if (be32_to_cpu(pi->ref_tag) == virt)
147 pi->ref_tag = cpu_to_be32(phys);
148
149 virt++;
150 phys++;
151 }
152
153 kunmap_atomic(pi);
154 }
155
156 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
157 }
158}
159
160/*
161 * Remap physical sector values in the reference tag to the virtual
162 * values expected by the block layer.
163 */
164void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
165{
166 const int tuple_sz = sizeof(struct t10_pi_tuple);
167 struct scsi_disk *sdkp;
168 struct bio *bio;
169 struct t10_pi_tuple *pi;
170 unsigned int j, intervals;
171 u32 phys, virt;
172
173 sdkp = scsi_disk(scmd->request->rq_disk);
174
175 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
176 return;
177
178 intervals = good_bytes / scsi_prot_interval(scmd);
179 phys = scsi_prot_ref_tag(scmd);
180
181 __rq_for_each_bio(bio, scmd->request) {
182 struct bio_integrity_payload *bip = bio_integrity(bio);
183 struct bio_vec iv;
184 struct bvec_iter iter;
185
186 virt = bip_get_seed(bip) & 0xffffffff;
187
188 bip_for_each_vec(iv, bip, iter) {
189 pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
190
191 for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
192
193 if (intervals == 0) {
194 kunmap_atomic(pi);
195 return;
196 }
197
198 if (be32_to_cpu(pi->ref_tag) == phys)
199 pi->ref_tag = cpu_to_be32(virt);
200
201 virt++;
202 phys++;
203 intervals--;
204 }
205
206 kunmap_atomic(pi);
207 }
208 }
209}
210