[SCSI] sd: Support for SCSI disk (SBC) Data Integrity Field
authorMartin K. Petersen <martin.petersen@oracle.com>
Thu, 17 Jul 2008 08:28:35 +0000 (04:28 -0400)
committerJames Bottomley <James.Bottomley@HansenPartnership.com>
Sat, 26 Jul 2008 19:14:56 +0000 (15:14 -0400)
Support for controllers and disks that implement DIF protection
information:

 - During command preparation the RDPROTECT/WRPROTECT must be set
   correctly if the target has DIF enabled.

 - READ(6) and WRITE(6) are not supported when DIF is on.

 - The controller must be told how to handle the I/O via the
   protection operation field in scsi_cmnd.

 - Refactor the I/O completion code that extracts failed LBA from the
   returned sense data and handle DIF failures correctly.

 - sd_dif.c implements the functions required to prepare and complete
   requests with protection information attached.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
drivers/scsi/Kconfig
drivers/scsi/Makefile
drivers/scsi/sd.c
drivers/scsi/sd.h
drivers/scsi/sd_dif.c [new file with mode: 0644]

index 26be540d1dd373ec79872fed9d97d71b3d8f16a1..c7f06298bd3c09242abd800cebb1b2b7dfb3f104 100644 (file)
@@ -63,6 +63,7 @@ comment "SCSI support type (disk, tape, CD-ROM)"
 config BLK_DEV_SD
        tristate "SCSI disk support"
        depends on SCSI
+       select CRC_T10DIF
        ---help---
          If you want to use SCSI hard disks, Fibre Channel disks,
          Serial ATA (SATA) or Parallel ATA (PATA) hard disks,
index a8149677de23613076b65e7f8a318a027de4c39c..72fd5043cfa1c14cef585db3077317ce8c6699a0 100644 (file)
@@ -151,6 +151,8 @@ scsi_mod-$(CONFIG_SCSI_PROC_FS)     += scsi_proc.o
 scsi_tgt-y                     += scsi_tgt_lib.o scsi_tgt_if.o
 
 sd_mod-objs    := sd.o
+sd_mod-$(CONFIG_BLK_DEV_INTEGRITY) += sd_dif.o
+
 sr_mod-objs    := sr.o sr_ioctl.o sr_vendor.o
 ncr53c8xx-flags-$(CONFIG_SCSI_ZALON) \
                := -DCONFIG_NCR53C8XX_PREFETCH -DSCSI_NCR_BIG_ENDIAN \
index 56b9501d12f3043c2af7c24b090fa2ea4a9d75bc..8e08d51a0f0531d8bf661dc0d3bf8f822d35c357 100644 (file)
@@ -373,6 +373,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
        struct scsi_cmnd *SCpnt;
        struct scsi_device *sdp = q->queuedata;
        struct gendisk *disk = rq->rq_disk;
+       struct scsi_disk *sdkp;
        sector_t block = rq->sector;
        unsigned int this_count = rq->nr_sectors;
        unsigned int timeout = sdp->timeout;
@@ -389,6 +390,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
        if (ret != BLKPREP_OK)
                goto out;
        SCpnt = rq->special;
+       sdkp = scsi_disk(disk);
 
        /* from here on until we're complete, any goto out
         * is used for a killable error condition */
@@ -478,6 +480,11 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
                }
                SCpnt->cmnd[0] = WRITE_6;
                SCpnt->sc_data_direction = DMA_TO_DEVICE;
+
+               if (blk_integrity_rq(rq) &&
+                   sd_dif_prepare(rq, block, sdp->sector_size) == -EIO)
+                       goto out;
+
        } else if (rq_data_dir(rq) == READ) {
                SCpnt->cmnd[0] = READ_6;
                SCpnt->sc_data_direction = DMA_FROM_DEVICE;
@@ -492,8 +499,12 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
                                        "writing" : "reading", this_count,
                                        rq->nr_sectors));
 
-       SCpnt->cmnd[1] = 0;
-       
+       /* Set RDPROTECT/WRPROTECT if disk is formatted with DIF */
+       if (scsi_host_dif_capable(sdp->host, sdkp->protection_type))
+               SCpnt->cmnd[1] = 1 << 5;
+       else
+               SCpnt->cmnd[1] = 0;
+
        if (block > 0xffffffff) {
                SCpnt->cmnd[0] += READ_16 - READ_6;
                SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
@@ -511,6 +522,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
                SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
                SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
        } else if ((this_count > 0xff) || (block > 0x1fffff) ||
+                  scsi_device_protection(SCpnt->device) ||
                   SCpnt->device->use_10_for_rw) {
                if (this_count > 0xffff)
                        this_count = 0xffff;
@@ -545,6 +557,10 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
        }
        SCpnt->sdb.length = this_count * sdp->sector_size;
 
+       /* If DIF or DIX is enabled, tell HBA how to handle request */
+       if (sdkp->protection_type || scsi_prot_sg_count(SCpnt))
+               sd_dif_op(SCpnt, sdkp->protection_type, scsi_prot_sg_count(SCpnt));
+
        /*
         * We shouldn't disconnect in the middle of a sector, so with a dumb
         * host adapter, it's safe to assume that we can at least transfer
@@ -939,6 +955,48 @@ static struct block_device_operations sd_fops = {
        .revalidate_disk        = sd_revalidate_disk,
 };
 
+static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
+{
+       u64 start_lba = scmd->request->sector;
+       u64 end_lba = scmd->request->sector + (scsi_bufflen(scmd) / 512);
+       u64 bad_lba;
+       int info_valid;
+
+       if (!blk_fs_request(scmd->request))
+               return 0;
+
+       info_valid = scsi_get_sense_info_fld(scmd->sense_buffer,
+                                            SCSI_SENSE_BUFFERSIZE,
+                                            &bad_lba);
+       if (!info_valid)
+               return 0;
+
+       if (scsi_bufflen(scmd) <= scmd->device->sector_size)
+               return 0;
+
+       if (scmd->device->sector_size < 512) {
+               /* only legitimate sector_size here is 256 */
+               start_lba <<= 1;
+               end_lba <<= 1;
+       } else {
+               /* be careful ... don't want any overflows */
+               u64 factor = scmd->device->sector_size / 512;
+               do_div(start_lba, factor);
+               do_div(end_lba, factor);
+       }
+
+       /* The bad lba was reported incorrectly, we have no idea where
+        * the error is.
+        */
+       if (bad_lba < start_lba  || bad_lba >= end_lba)
+               return 0;
+
+       /* This computation should always be done in terms of
+        * the resolution of the device's medium.
+        */
+       return (bad_lba - start_lba) * scmd->device->sector_size;
+}
+
 /**
  *     sd_done - bottom half handler: called when the lower level
  *     driver has completed (successfully or otherwise) a scsi command.
@@ -949,15 +1007,10 @@ static struct block_device_operations sd_fops = {
 static int sd_done(struct scsi_cmnd *SCpnt)
 {
        int result = SCpnt->result;
-       unsigned int xfer_size = scsi_bufflen(SCpnt);
-       unsigned int good_bytes = result ? 0 : xfer_size;
-       u64 start_lba = SCpnt->request->sector;
-       u64 end_lba = SCpnt->request->sector + (xfer_size / 512);
-       u64 bad_lba;
+       unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);
        struct scsi_sense_hdr sshdr;
        int sense_valid = 0;
        int sense_deferred = 0;
-       int info_valid;
 
        if (result) {
                sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
@@ -982,36 +1035,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
        switch (sshdr.sense_key) {
        case HARDWARE_ERROR:
        case MEDIUM_ERROR:
-               if (!blk_fs_request(SCpnt->request))
-                       goto out;
-               info_valid = scsi_get_sense_info_fld(SCpnt->sense_buffer,
-                                                    SCSI_SENSE_BUFFERSIZE,
-                                                    &bad_lba);
-               if (!info_valid)
-                       goto out;
-               if (xfer_size <= SCpnt->device->sector_size)
-                       goto out;
-               if (SCpnt->device->sector_size < 512) {
-                       /* only legitimate sector_size here is 256 */
-                       start_lba <<= 1;
-                       end_lba <<= 1;
-               } else {
-                       /* be careful ... don't want any overflows */
-                       u64 factor = SCpnt->device->sector_size / 512;
-                       do_div(start_lba, factor);
-                       do_div(end_lba, factor);
-               }
-
-               if (bad_lba < start_lba  || bad_lba >= end_lba)
-                       /* the bad lba was reported incorrectly, we have
-                        * no idea where the error is
-                        */
-                       goto out;
-
-               /* This computation should always be done in terms of
-                * the resolution of the device's medium.
-                */
-               good_bytes = (bad_lba - start_lba)*SCpnt->device->sector_size;
+               good_bytes = sd_completed_bytes(SCpnt);
                break;
        case RECOVERED_ERROR:
        case NO_SENSE:
@@ -1021,10 +1045,23 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                scsi_print_sense("sd", SCpnt);
                SCpnt->result = 0;
                memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
-               good_bytes = xfer_size;
+               good_bytes = scsi_bufflen(SCpnt);
+               break;
+       case ABORTED_COMMAND:
+               if (sshdr.asc == 0x10) { /* DIF: Disk detected corruption */
+                       scsi_print_result(SCpnt);
+                       scsi_print_sense("sd", SCpnt);
+                       good_bytes = sd_completed_bytes(SCpnt);
+               }
                break;
        case ILLEGAL_REQUEST:
-               if (SCpnt->device->use_10_for_rw &&
+               if (sshdr.asc == 0x10) { /* DIX: HBA detected corruption */
+                       scsi_print_result(SCpnt);
+                       scsi_print_sense("sd", SCpnt);
+                       good_bytes = sd_completed_bytes(SCpnt);
+               }
+               if (!scsi_device_protection(SCpnt->device) &&
+                   SCpnt->device->use_10_for_rw &&
                    (SCpnt->cmnd[0] == READ_10 ||
                     SCpnt->cmnd[0] == WRITE_10))
                        SCpnt->device->use_10_for_rw = 0;
@@ -1037,6 +1074,9 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                break;
        }
  out:
+       if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
+               sd_dif_complete(SCpnt, good_bytes);
+
        return good_bytes;
 }
 
@@ -1826,6 +1866,7 @@ static int sd_probe(struct device *dev)
 
        dev_set_drvdata(dev, sdkp);
        add_disk(gd);
+       sd_dif_config_host(sdkp);
 
        sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
                  sdp->removable ? "removable " : "");
index 86b18d4170fe240ad14ce796270db9c45cd2f373..550b2f70a1f8330f93fea284c19f13554297ef86 100644 (file)
@@ -82,4 +82,29 @@ enum sd_dif_target_protection_types {
        SD_DIF_TYPE3_PROTECTION = 0x3,
 };
 
+/*
+ * Data Integrity Field tuple.
+ */
+struct sd_dif_tuple {
+       __be16 guard_tag;       /* Checksum */
+       __be16 app_tag;         /* Opaque storage */
+       __be32 ref_tag;         /* Target LBA or indirect LBA */
+};
+
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+
+extern void sd_dif_op(struct scsi_cmnd *, unsigned int, unsigned int);
+extern void sd_dif_config_host(struct scsi_disk *);
+extern int sd_dif_prepare(struct request *rq, sector_t, unsigned int);
+extern void sd_dif_complete(struct scsi_cmnd *, unsigned int);
+
+#else /* CONFIG_BLK_DEV_INTEGRITY */
+
+#define sd_dif_op(a, b, c)                     do { } while (0)
+#define sd_dif_config_host(a)                  do { } while (0)
+#define sd_dif_prepare(a, b, c)                        (0)
+#define sd_dif_complete(a, b)                  (0)
+
+#endif /* CONFIG_BLK_DEV_INTEGRITY */
+
 #endif /* _SCSI_DISK_H */
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
new file mode 100644 (file)
index 0000000..4d17f3d
--- /dev/null
@@ -0,0 +1,538 @@
+/*
+ * sd_dif.c - SCSI Data Integrity Field
+ *
+ * Copyright (C) 2007, 2008 Oracle Corporation
+ * Written by: Martin K. Petersen <martin.petersen@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
+ * USA.
+ *
+ */
+
+#include <linux/blkdev.h>
+#include <linux/crc-t10dif.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsicam.h>
+
+#include <net/checksum.h>
+
+#include "sd.h"
+
+typedef __u16 (csum_fn) (void *, unsigned int);
+
+static __u16 sd_dif_crc_fn(void *data, unsigned int len)
+{
+       return cpu_to_be16(crc_t10dif(data, len));
+}
+
+static __u16 sd_dif_ip_fn(void *data, unsigned int len)
+{
+       return ip_compute_csum(data, len);
+}
+
+/*
+ * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
+ * 16 bit app tag, 32 bit reference tag.
+ */
+static void sd_dif_type1_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+       void *buf = bix->data_buf;
+       struct sd_dif_tuple *sdt = bix->prot_buf;
+       sector_t sector = bix->sector;
+       unsigned int i;
+
+       for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+               sdt->guard_tag = fn(buf, bix->sector_size);
+               sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
+               sdt->app_tag = 0;
+
+               buf += bix->sector_size;
+               sector++;
+       }
+}
+
+static void sd_dif_type1_generate_crc(struct blk_integrity_exchg *bix)
+{
+       sd_dif_type1_generate(bix, sd_dif_crc_fn);
+}
+
+static void sd_dif_type1_generate_ip(struct blk_integrity_exchg *bix)
+{
+       sd_dif_type1_generate(bix, sd_dif_ip_fn);
+}
+
+static int sd_dif_type1_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+       void *buf = bix->data_buf;
+       struct sd_dif_tuple *sdt = bix->prot_buf;
+       sector_t sector = bix->sector;
+       unsigned int i;
+       __u16 csum;
+
+       for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+               /* Unwritten sectors */
+               if (sdt->app_tag == 0xffff)
+                       return 0;
+
+               /* Bad ref tag received from disk */
+               if (sdt->ref_tag == 0xffffffff) {
+                       printk(KERN_ERR
+                              "%s: bad phys ref tag on sector %lu\n",
+                              bix->disk_name, (unsigned long)sector);
+                       return -EIO;
+               }
+
+               if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
+                       printk(KERN_ERR
+                              "%s: ref tag error on sector %lu (rcvd %u)\n",
+                              bix->disk_name, (unsigned long)sector,
+                              be32_to_cpu(sdt->ref_tag));
+                       return -EIO;
+               }
+
+               csum = fn(buf, bix->sector_size);
+
+               if (sdt->guard_tag != csum) {
+                       printk(KERN_ERR "%s: guard tag error on sector %lu " \
+                              "(rcvd %04x, data %04x)\n", bix->disk_name,
+                              (unsigned long)sector,
+                              be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
+                       return -EIO;
+               }
+
+               buf += bix->sector_size;
+               sector++;
+       }
+
+       return 0;
+}
+
+static int sd_dif_type1_verify_crc(struct blk_integrity_exchg *bix)
+{
+       return sd_dif_type1_verify(bix, sd_dif_crc_fn);
+}
+
+static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
+{
+       return sd_dif_type1_verify(bix, sd_dif_ip_fn);
+}
+
+/*
+ * Functions for interleaving and deinterleaving application tags
+ */
+static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+       struct sd_dif_tuple *sdt = prot;
+       char *tag = tag_buf;
+       unsigned int i, j;
+
+       for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
+               sdt->app_tag = tag[j] << 8 | tag[j+1];
+               BUG_ON(sdt->app_tag == 0xffff);
+       }
+}
+
+static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+       struct sd_dif_tuple *sdt = prot;
+       char *tag = tag_buf;
+       unsigned int i, j;
+
+       for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
+               tag[j] = (sdt->app_tag & 0xff00) >> 8;
+               tag[j+1] = sdt->app_tag & 0xff;
+       }
+}
+
+static struct blk_integrity dif_type1_integrity_crc = {
+       .name                   = "T10-DIF-TYPE1-CRC",
+       .generate_fn            = sd_dif_type1_generate_crc,
+       .verify_fn              = sd_dif_type1_verify_crc,
+       .get_tag_fn             = sd_dif_type1_get_tag,
+       .set_tag_fn             = sd_dif_type1_set_tag,
+       .tuple_size             = sizeof(struct sd_dif_tuple),
+       .tag_size               = 0,
+};
+
+static struct blk_integrity dif_type1_integrity_ip = {
+       .name                   = "T10-DIF-TYPE1-IP",
+       .generate_fn            = sd_dif_type1_generate_ip,
+       .verify_fn              = sd_dif_type1_verify_ip,
+       .get_tag_fn             = sd_dif_type1_get_tag,
+       .set_tag_fn             = sd_dif_type1_set_tag,
+       .tuple_size             = sizeof(struct sd_dif_tuple),
+       .tag_size               = 0,
+};
+
+
+/*
+ * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque
+ * tag space.
+ */
+static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+       void *buf = bix->data_buf;
+       struct sd_dif_tuple *sdt = bix->prot_buf;
+       unsigned int i;
+
+       for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+               sdt->guard_tag = fn(buf, bix->sector_size);
+               sdt->ref_tag = 0;
+               sdt->app_tag = 0;
+
+               buf += bix->sector_size;
+       }
+}
+
+static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix)
+{
+       sd_dif_type3_generate(bix, sd_dif_crc_fn);
+}
+
+static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix)
+{
+       sd_dif_type3_generate(bix, sd_dif_ip_fn);
+}
+
+static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+       void *buf = bix->data_buf;
+       struct sd_dif_tuple *sdt = bix->prot_buf;
+       sector_t sector = bix->sector;
+       unsigned int i;
+       __u16 csum;
+
+       for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+               /* Unwritten sectors */
+               if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
+                       return 0;
+
+               csum = fn(buf, bix->sector_size);
+
+               if (sdt->guard_tag != csum) {
+                       printk(KERN_ERR "%s: guard tag error on sector %lu " \
+                              "(rcvd %04x, data %04x)\n", bix->disk_name,
+                              (unsigned long)sector,
+                              be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
+                       return -EIO;
+               }
+
+               buf += bix->sector_size;
+               sector++;
+       }
+
+       return 0;
+}
+
+static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix)
+{
+       return sd_dif_type3_verify(bix, sd_dif_crc_fn);
+}
+
+static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
+{
+       return sd_dif_type3_verify(bix, sd_dif_ip_fn);
+}
+
+static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+       struct sd_dif_tuple *sdt = prot;
+       char *tag = tag_buf;
+       unsigned int i, j;
+
+       for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) {
+               sdt->app_tag = tag[j] << 8 | tag[j+1];
+               sdt->ref_tag = tag[j+2] << 24 | tag[j+3] << 16 |
+                       tag[j+4] << 8 | tag[j+5];
+       }
+}
+
+static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+       struct sd_dif_tuple *sdt = prot;
+       char *tag = tag_buf;
+       unsigned int i, j;
+
+       for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
+               tag[j] = (sdt->app_tag & 0xff00) >> 8;
+               tag[j+1] = sdt->app_tag & 0xff;
+               tag[j+2] = (sdt->ref_tag & 0xff000000) >> 24;
+               tag[j+3] = (sdt->ref_tag & 0xff0000) >> 16;
+               tag[j+4] = (sdt->ref_tag & 0xff00) >> 8;
+               tag[j+5] = sdt->ref_tag & 0xff;
+               BUG_ON(sdt->app_tag == 0xffff || sdt->ref_tag == 0xffffffff);
+       }
+}
+
+static struct blk_integrity dif_type3_integrity_crc = {
+       .name                   = "T10-DIF-TYPE3-CRC",
+       .generate_fn            = sd_dif_type3_generate_crc,
+       .verify_fn              = sd_dif_type3_verify_crc,
+       .get_tag_fn             = sd_dif_type3_get_tag,
+       .set_tag_fn             = sd_dif_type3_set_tag,
+       .tuple_size             = sizeof(struct sd_dif_tuple),
+       .tag_size               = 0,
+};
+
+static struct blk_integrity dif_type3_integrity_ip = {
+       .name                   = "T10-DIF-TYPE3-IP",
+       .generate_fn            = sd_dif_type3_generate_ip,
+       .verify_fn              = sd_dif_type3_verify_ip,
+       .get_tag_fn             = sd_dif_type3_get_tag,
+       .set_tag_fn             = sd_dif_type3_set_tag,
+       .tuple_size             = sizeof(struct sd_dif_tuple),
+       .tag_size               = 0,
+};
+
+/*
+ * Configure exchange of protection information between OS and HBA.
+ */
+void sd_dif_config_host(struct scsi_disk *sdkp)
+{
+       struct scsi_device *sdp = sdkp->device;
+       struct gendisk *disk = sdkp->disk;
+       u8 type = sdkp->protection_type;
+
+       /* If this HBA doesn't support DIX, resort to normal I/O or DIF */
+       if (scsi_host_dix_capable(sdp->host, type) == 0) {
+
+               if (type == SD_DIF_TYPE0_PROTECTION)
+                       return;
+
+               if (scsi_host_dif_capable(sdp->host, type) == 0) {
+                       sd_printk(KERN_INFO, sdkp, "Type %d protection " \
+                                 "unsupported by HBA. Disabling DIF.\n", type);
+                       sdkp->protection_type = 0;
+                       return;
+               }
+
+               sd_printk(KERN_INFO, sdkp, "Enabling DIF Type %d protection\n",
+                         type);
+
+               return;
+       }
+
+       /* Enable DMA of protection information */
+       if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
+               if (type == SD_DIF_TYPE3_PROTECTION)
+                       blk_integrity_register(disk, &dif_type3_integrity_ip);
+               else
+                       blk_integrity_register(disk, &dif_type1_integrity_ip);
+       else
+               if (type == SD_DIF_TYPE3_PROTECTION)
+                       blk_integrity_register(disk, &dif_type3_integrity_crc);
+               else
+                       blk_integrity_register(disk, &dif_type1_integrity_crc);
+
+       sd_printk(KERN_INFO, sdkp,
+                 "Enabling %s integrity protection\n", disk->integrity->name);
+
+       /* Signal to block layer that we support sector tagging */
+       if (type && sdkp->ATO) {
+               if (type == SD_DIF_TYPE3_PROTECTION)
+                       disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
+               else
+                       disk->integrity->tag_size = sizeof(u16);
+
+               sd_printk(KERN_INFO, sdkp, "DIF application tag size %u\n",
+                         disk->integrity->tag_size);
+       }
+}
+
+/*
+ * DIF DMA operation magic decoder ring.
+ */
+void sd_dif_op(struct scsi_cmnd *scmd, unsigned int dif, unsigned int dix)
+{
+       int csum_convert, prot_op;
+
+       prot_op = 0;
+
+       /* Convert checksum? */
+       if (scsi_host_get_guard(scmd->device->host) != SHOST_DIX_GUARD_CRC)
+               csum_convert = 1;
+       else
+               csum_convert = 0;
+
+       switch (scmd->cmnd[0]) {
+       case READ_10:
+       case READ_12:
+       case READ_16:
+               if (dif && dix)
+                       if (csum_convert)
+                               prot_op = SCSI_PROT_READ_CONVERT;
+                       else
+                               prot_op = SCSI_PROT_READ_PASS;
+               else if (dif && !dix)
+                       prot_op = SCSI_PROT_READ_STRIP;
+               else if (!dif && dix)
+                       prot_op = SCSI_PROT_READ_INSERT;
+
+               break;
+
+       case WRITE_10:
+       case WRITE_12:
+       case WRITE_16:
+               if (dif && dix)
+                       if (csum_convert)
+                               prot_op = SCSI_PROT_WRITE_CONVERT;
+                       else
+                               prot_op = SCSI_PROT_WRITE_PASS;
+               else if (dif && !dix)
+                       prot_op = SCSI_PROT_WRITE_INSERT;
+               else if (!dif && dix)
+                       prot_op = SCSI_PROT_WRITE_STRIP;
+
+               break;
+       }
+
+       scsi_set_prot_op(scmd, prot_op);
+       scsi_set_prot_type(scmd, dif);
+}
+
+/*
+ * The virtual start sector is the one that was originally submitted
+ * by the block layer. Due to partitioning, MD/DM cloning, etc. the
+ * actual physical start sector is likely to be different.  Remap
+ * protection information to match the physical LBA.
+ *
+ * From a protocol perspective there's a slight difference between
+ * Type 1 and 2.  The latter uses 32-byte CDBs exclusively, and the
+ * reference tag is seeded in the CDB.  This gives us the potential to
+ * avoid virt->phys remapping during write.  However, at read time we
+ * don't know whether the virt sector is the same as when we wrote it
+ * (we could be reading from real disk as opposed to MD/DM device.  So
+ * we always remap Type 2 making it identical to Type 1.
+ *
+ * Type 3 does not have a reference tag so no remapping is required.
+ */
+int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_sz)
+{
+       const int tuple_sz = sizeof(struct sd_dif_tuple);
+       struct bio *bio;
+       struct scsi_disk *sdkp;
+       struct sd_dif_tuple *sdt;
+       unsigned int i, j;
+       u32 phys, virt;
+
+       /* Already remapped? */
+       if (rq->cmd_flags & REQ_INTEGRITY)
+               return 0;
+
+       sdkp = rq->bio->bi_bdev->bd_disk->private_data;
+
+       if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
+               return 0;
+
+       rq->cmd_flags |= REQ_INTEGRITY;
+       phys = hw_sector & 0xffffffff;
+
+       __rq_for_each_bio(bio, rq) {
+               struct bio_vec *iv;
+
+               virt = bio->bi_integrity->bip_sector & 0xffffffff;
+
+               bip_for_each_vec(iv, bio->bi_integrity, i) {
+                       sdt = kmap_atomic(iv->bv_page, KM_USER0)
+                               + iv->bv_offset;
+
+                       for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
+
+                               if (be32_to_cpu(sdt->ref_tag) != virt)
+                                       goto error;
+
+                               sdt->ref_tag = cpu_to_be32(phys);
+                               virt++;
+                               phys++;
+                       }
+
+                       kunmap_atomic(sdt, KM_USER0);
+               }
+       }
+
+       return 0;
+
+error:
+       kunmap_atomic(sdt, KM_USER0);
+       sd_printk(KERN_ERR, sdkp, "%s: virt %u, phys %u, ref %u\n",
+                 __func__, virt, phys, be32_to_cpu(sdt->ref_tag));
+
+       return -EIO;
+}
+
+/*
+ * Remap physical sector values in the reference tag to the virtual
+ * values expected by the block layer.
+ */
+void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
+{
+       const int tuple_sz = sizeof(struct sd_dif_tuple);
+       struct scsi_disk *sdkp;
+       struct bio *bio;
+       struct sd_dif_tuple *sdt;
+       unsigned int i, j, sectors, sector_sz;
+       u32 phys, virt;
+
+       sdkp = scsi_disk(scmd->request->rq_disk);
+
+       if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
+               return;
+
+       sector_sz = scmd->device->sector_size;
+       sectors = good_bytes / sector_sz;
+
+       phys = scmd->request->sector & 0xffffffff;
+       if (sector_sz == 4096)
+               phys >>= 3;
+
+       __rq_for_each_bio(bio, scmd->request) {
+               struct bio_vec *iv;
+
+               virt = bio->bi_integrity->bip_sector & 0xffffffff;
+
+               bip_for_each_vec(iv, bio->bi_integrity, i) {
+                       sdt = kmap_atomic(iv->bv_page, KM_USER0)
+                               + iv->bv_offset;
+
+                       for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
+
+                               if (sectors == 0) {
+                                       kunmap_atomic(sdt, KM_USER0);
+                                       return;
+                               }
+
+                               if (be32_to_cpu(sdt->ref_tag) != phys &&
+                                   sdt->app_tag != 0xffff)
+                                       sdt->ref_tag = 0xffffffff; /* Bad ref */
+                               else
+                                       sdt->ref_tag = cpu_to_be32(virt);
+
+                               virt++;
+                               phys++;
+                               sectors--;
+                       }
+
+                       kunmap_atomic(sdt, KM_USER0);
+               }
+       }
+}
+