2 files changed, 25 insertions, 8 deletions

diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
index 29a9a53cdd1..9f070f0d0f2 100644
--- a/drivers/scsi/scsi_transport_spi.c
+++ b/drivers/scsi/scsi_transport_spi.c
@@ -47,6 +47,7 @@
 
 /* Private data accessors (keep these out of the header file) */
 #define spi_dv_pending(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_pending)
+#define spi_dv_in_progress(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_in_progress)
 #define spi_dv_mutex(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_mutex)
 
 struct spi_internal {
@@ -240,6 +241,7 @@ static int spi_setup_transport_attrs(struct transport_container *tc,
         spi_pcomp_en(starget) = 0;
         spi_hold_mcs(starget) = 0;
         spi_dv_pending(starget) = 0;
+        spi_dv_in_progress(starget) = 0;
         spi_initial_dv(starget) = 0;
         mutex_init(&spi_dv_mutex(starget));
 
@@ -830,28 +832,37 @@ spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)
         DV_SET(period, spi_min_period(starget));
         /* try QAS requests; this should be harmless to set if the
          * target supports it */
-        if (scsi_device_qas(sdev))
+        if (scsi_device_qas(sdev)) {
                 DV_SET(qas, 1);
-        /* Also try IU transfers */
-        if (scsi_device_ius(sdev))
+        } else {
+                DV_SET(qas, 0);
+        }
+
+        if (scsi_device_ius(sdev) && spi_min_period(starget) < 9) {
+                /* This u320 (or u640). Set IU transfers */
                 DV_SET(iu, 1);
-        if (spi_min_period(starget) < 9) {
-                /* This u320 (or u640). Ignore the coupled parameters
-                 * like DT and IU, but set the optional ones */
+                /* Then set the optional parameters */
                 DV_SET(rd_strm, 1);
                 DV_SET(wr_flow, 1);
                 DV_SET(rti, 1);
                 if (spi_min_period(starget) == 8)
                         DV_SET(pcomp_en, 1);
+        } else {
+                DV_SET(iu, 0);
         }
+
         /* now that we've done all this, actually check the bus
          * signal type (if known).  Some devices are stupid on
          * a SE bus and still claim they can try LVD only settings */
         if (i->f->get_signalling)
                 i->f->get_signalling(shost);
         if (spi_signalling(shost) == SPI_SIGNAL_SE ||
-            spi_signalling(shost) == SPI_SIGNAL_HVD)
+            spi_signalling(shost) == SPI_SIGNAL_HVD ||
+            !scsi_device_dt(sdev)) {
                 DV_SET(dt, 0);
+        } else {
+                DV_SET(dt, 1);
+        }
         /* Do the read only INQUIRY tests */
         spi_dv_retrain(sdev, buffer, buffer + sdev->inquiry_len,
                        spi_dv_device_compare_inquiry);
@@ -907,6 +918,10 @@ spi_dv_device(struct scsi_device *sdev)
         if (unlikely(scsi_device_get(sdev)))
                 return;
 
+        if (unlikely(spi_dv_in_progress(starget)))
+                return;
+        spi_dv_in_progress(starget) = 1;
+
         buffer = kzalloc(len, GFP_KERNEL);
 
         if (unlikely(!buffer))
@@ -938,6 +953,7 @@ spi_dv_device(struct scsi_device *sdev)
  out_free:
         kfree(buffer);
  out_put:
+        spi_dv_in_progress(starget) = 0;
         scsi_device_put(sdev);
 }
 EXPORT_SYMBOL(spi_dv_device);
diff --git a/include/scsi/scsi_transport_spi.h b/include/scsi/scsi_transport_spi.h
index 302680c0c0d..da180f73847 100644
--- a/include/scsi/scsi_transport_spi.h
+++ b/include/scsi/scsi_transport_spi.h
@@ -53,7 +53,8 @@ struct spi_transport_attrs {
         unsigned int support_ius; /* support Information Units */
         unsigned int support_qas; /* supports quick arbitration and selection */
         /* Private Fields */
-        unsigned int dv_pending:1; /* Internal flag */
+        unsigned int dv_pending:1; /* Internal flag: DV Requested */
+        unsigned int dv_in_progress:1;  /* Internal: DV started */
         struct mutex dv_mutex; /* semaphore to serialise dv */
 };