[SCSI] libsas,libata: fix ->change_queue_{depth|type} for sata devices

Pass queue_depth change requests to libata, and prevent queue_type
changes for ATA devices.

Otherwise:
1/ we do not honor the libata specific restrictions on the queue depth
2/ libsas drivers that do not set sdev->tagged_supported are unable to
   change the queue_depth of ata devices via sysfs

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 46d087f..19ba770 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1215,25 +1215,15 @@
 }
 
 /**
- *	ata_scsi_change_queue_depth - SCSI callback for queue depth config
- *	@sdev: SCSI device to configure queue depth for
- *	@queue_depth: new queue depth
- *	@reason: calling context
+ *	__ata_change_queue_depth - helper for ata_scsi_change_queue_depth
  *
- *	This is libata standard hostt->change_queue_depth callback.
- *	SCSI will call into this callback when user tries to set queue
- *	depth via sysfs.
+ *	libsas and libata have different approaches for associating a sdev to
+ *	its ata_port.
  *
- *	LOCKING:
- *	SCSI layer (we don't care)
- *
- *	RETURNS:
- *	Newly configured queue depth.
  */
-int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth,
-				int reason)
+int __ata_change_queue_depth(struct ata_port *ap, struct scsi_device *sdev,
+			     int queue_depth, int reason)
 {
-	struct ata_port *ap = ata_shost_to_port(sdev->host);
 	struct ata_device *dev;
 	unsigned long flags;
 
@@ -1269,6 +1259,30 @@
 }
 
 /**
+ *	ata_scsi_change_queue_depth - SCSI callback for queue depth config
+ *	@sdev: SCSI device to configure queue depth for
+ *	@queue_depth: new queue depth
+ *	@reason: calling context
+ *
+ *	This is libata standard hostt->change_queue_depth callback.
+ *	SCSI will call into this callback when user tries to set queue
+ *	depth via sysfs.
+ *
+ *	LOCKING:
+ *	SCSI layer (we don't care)
+ *
+ *	RETURNS:
+ *	Newly configured queue depth.
+ */
+int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth,
+				int reason)
+{
+	struct ata_port *ap = ata_shost_to_port(sdev->host);
+
+	return __ata_change_queue_depth(ap, sdev, queue_depth, reason);
+}
+
+/**
  *	ata_scsi_start_stop_xlat - Translate SCSI START STOP UNIT command
  *	@qc: Storage for translated ATA taskfile
  *