[SCSI] sd: Detach DIF from block integrity infrastructure

So far we have only issued DIF commands if CONFIG_BLK_DEV_INTEGRITY is
enabled.  However, communication between initiator and target should be
independent of protection information DMA.  There are DIF-only host
adapters coming out that will be able to take advantage of this.

Move the relevant DIF bits to sd.c.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 42 insertions, 19 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8dd96dcd716c..1e0a0b07dab6 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -370,6 +370,31 @@ static void scsi_disk_put(struct scsi_disk *sdkp)
         mutex_unlock(&sd_ref_mutex);
 }
 
+static void sd_prot_op(struct scsi_cmnd *scmd, unsigned int dif)
+{
+        unsigned int prot_op = SCSI_PROT_NORMAL;
+        unsigned int dix = scsi_prot_sg_count(scmd);
+
+        if (scmd->sc_data_direction == DMA_FROM_DEVICE) {
+                if (dif && dix)
+                        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;
+        } else {
+                if (dif && dix)
+                        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;
+        }
+
+        scsi_set_prot_op(scmd, prot_op);
+        scsi_set_prot_type(scmd, dif);
+}
+
 /**
  *      sd_init_command - build a scsi (read or write) command from
  *      information in the request structure.
@@ -578,8 +603,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
 
         /* If DIF or DIX is enabled, tell HBA how to handle request */
         if (host_dif || scsi_prot_sg_count(SCpnt))
-                sd_dif_op(SCpnt, host_dif, scsi_prot_sg_count(SCpnt),
-                          sdkp->protection_type);
+                sd_prot_op(SCpnt, host_dif);
 
         /*
          * We shouldn't disconnect in the middle of a sector, so with a dumb
@@ -1238,34 +1262,33 @@ void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)
         u8 type;
 
         if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0)
-                type = 0;
-        else
-                type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
+                return;
+
+        type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
+
+        if (type == sdkp->protection_type || !sdkp->first_scan)
+                return;
 
         sdkp->protection_type = type;
 
         switch (type) {
-        case SD_DIF_TYPE0_PROTECTION:
         case SD_DIF_TYPE1_PROTECTION:
         case SD_DIF_TYPE3_PROTECTION:
                 break;
 
-        case SD_DIF_TYPE2_PROTECTION:
-                sd_printk(KERN_ERR, sdkp, "formatted with DIF Type 2 "  \
-                          "protection which is currently unsupported. " \
-                          "Disabling disk!\n");
-                goto disable;
-
         default:
-                sd_printk(KERN_ERR, sdkp, "formatted with unknown "     \
-                          "protection type %d. Disabling disk!\n", type);
-                goto disable;
+                sd_printk(KERN_ERR, sdkp, "formatted with unsupported " \
+                          "protection type %u. Disabling disk!\n", type);
+                sdkp->capacity = 0;
+                return;
         }
 
-        return;
-
-disable:
-        sdkp->capacity = 0;
+        if (scsi_host_dif_capable(sdp->host, type))
+                sd_printk(KERN_NOTICE, sdkp,
+                          "Enabling DIF Type %u protection\n", type);
+        else
+                sd_printk(KERN_NOTICE, sdkp,
+                          "Disabling DIF Type %u protection\n", type);
 }
 
 static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,