[SCSI] sd: Support for SCSI disk (SBC) Data Integrity Field

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>

1 files changed, 81 insertions, 40 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 56b9501d12f3..8e08d51a0f05 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -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 " : "");