[SCSI] SPI transport class: misc DV fixes

Key more of the domain validation settings off the inquiry data from
the disk (in particular, don't try IU or DT unless the disk claims to
support them.

Also add a new dv_in_progress flag to prevent recursive DV.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

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);

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 */
 };