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 */
sd_dif_config_host(struct scsi_disk * sdkp)41 void 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 int dif, dix;
47
48 dif = scsi_host_dif_capable(sdp->host, type);
49 dix = scsi_host_dix_capable(sdp->host, type);
50
51 if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
52 dif = 0; dix = 1;
53 }
54
55 if (!dix)
56 return;
57
58 /* Enable DMA of protection information */
59 if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP) {
60 if (type == SD_DIF_TYPE3_PROTECTION)
61 blk_integrity_register(disk, &t10_pi_type3_ip);
62 else
63 blk_integrity_register(disk, &t10_pi_type1_ip);
64
65 disk->integrity->flags |= BLK_INTEGRITY_IP_CHECKSUM;
66 } else
67 if (type == SD_DIF_TYPE3_PROTECTION)
68 blk_integrity_register(disk, &t10_pi_type3_crc);
69 else
70 blk_integrity_register(disk, &t10_pi_type1_crc);
71
72 sd_printk(KERN_NOTICE, sdkp,
73 "Enabling DIX %s protection\n", disk->integrity->name);
74
75 /* Signal to block layer that we support sector tagging */
76 if (dif && type) {
77
78 disk->integrity->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
79
80 if (!sdkp->ATO)
81 return;
82
83 if (type == SD_DIF_TYPE3_PROTECTION)
84 disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
85 else
86 disk->integrity->tag_size = sizeof(u16);
87
88 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
89 disk->integrity->tag_size);
90 }
91 }
92
93 /*
94 * The virtual start sector is the one that was originally submitted
95 * by the block layer. Due to partitioning, MD/DM cloning, etc. the
96 * actual physical start sector is likely to be different. Remap
97 * protection information to match the physical LBA.
98 *
99 * From a protocol perspective there's a slight difference between
100 * Type 1 and 2. The latter uses 32-byte CDBs exclusively, and the
101 * reference tag is seeded in the CDB. This gives us the potential to
102 * avoid virt->phys remapping during write. However, at read time we
103 * don't know whether the virt sector is the same as when we wrote it
104 * (we could be reading from real disk as opposed to MD/DM device. So
105 * we always remap Type 2 making it identical to Type 1.
106 *
107 * Type 3 does not have a reference tag so no remapping is required.
108 */
sd_dif_prepare(struct scsi_cmnd * scmd)109 void sd_dif_prepare(struct scsi_cmnd *scmd)
110 {
111 const int tuple_sz = sizeof(struct t10_pi_tuple);
112 struct bio *bio;
113 struct scsi_disk *sdkp;
114 struct t10_pi_tuple *pi;
115 u32 phys, virt;
116
117 sdkp = scsi_disk(scmd->request->rq_disk);
118
119 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
120 return;
121
122 phys = scsi_prot_ref_tag(scmd);
123
124 __rq_for_each_bio(bio, scmd->request) {
125 struct bio_integrity_payload *bip = bio_integrity(bio);
126 struct bio_vec iv;
127 struct bvec_iter iter;
128 unsigned int j;
129
130 /* Already remapped? */
131 if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
132 break;
133
134 virt = bip_get_seed(bip) & 0xffffffff;
135
136 bip_for_each_vec(iv, bip, iter) {
137 pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
138
139 for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
140
141 if (be32_to_cpu(pi->ref_tag) == virt)
142 pi->ref_tag = cpu_to_be32(phys);
143
144 virt++;
145 phys++;
146 }
147
148 kunmap_atomic(pi);
149 }
150
151 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
152 }
153 }
154
155 /*
156 * Remap physical sector values in the reference tag to the virtual
157 * values expected by the block layer.
158 */
sd_dif_complete(struct scsi_cmnd * scmd,unsigned int good_bytes)159 void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
160 {
161 const int tuple_sz = sizeof(struct t10_pi_tuple);
162 struct scsi_disk *sdkp;
163 struct bio *bio;
164 struct t10_pi_tuple *pi;
165 unsigned int j, intervals;
166 u32 phys, virt;
167
168 sdkp = scsi_disk(scmd->request->rq_disk);
169
170 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
171 return;
172
173 intervals = good_bytes / scsi_prot_interval(scmd);
174 phys = scsi_prot_ref_tag(scmd);
175
176 __rq_for_each_bio(bio, scmd->request) {
177 struct bio_integrity_payload *bip = bio_integrity(bio);
178 struct bio_vec iv;
179 struct bvec_iter iter;
180
181 virt = bip_get_seed(bip) & 0xffffffff;
182
183 bip_for_each_vec(iv, bip, iter) {
184 pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
185
186 for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
187
188 if (intervals == 0) {
189 kunmap_atomic(pi);
190 return;
191 }
192
193 if (be32_to_cpu(pi->ref_tag) == phys)
194 pi->ref_tag = cpu_to_be32(virt);
195
196 virt++;
197 phys++;
198 intervals--;
199 }
200
201 kunmap_atomic(pi);
202 }
203 }
204 }
205
206