[PATCH] libata-ncq: implement NCQ device configuration

Now that all NCQ related stuff are in place, implement NCQ device
configuration and bump ATA_MAX_QUEUE to 32 thus activating NCQ
support.

Original implementation is from Jens Axboe.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 9bef68c7c1de..996058af1bcd 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -41,6 +41,7 @@
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_request.h>
+#include <scsi/scsi_tcq.h>
 #include <scsi/scsi_transport.h>
 #include <linux/libata.h>
 #include <linux/hdreg.h>
@@ -684,6 +685,14 @@ static void ata_scsi_dev_config(struct scsi_device *sdev,
 		request_queue_t *q = sdev->request_queue;
 		blk_queue_max_hw_segments(q, q->max_hw_segments - 1);
 	}
+
+	if (dev->flags & ATA_DFLAG_NCQ) {
+		int depth;
+
+		depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
+		depth = min(ATA_MAX_QUEUE - 1, depth);
+		scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
+	}
 }
 
 /**
@@ -718,6 +727,43 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 }
 
 /**
+ *	ata_scsi_change_queue_depth - SCSI callback for queue depth config
+ *	@sdev: SCSI device to configure queue depth for
+ *	@queue_depth: new 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.
+ *
+ *	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)
+{
+	struct ata_port *ap = ata_shost_to_port(sdev->host);
+	struct ata_device *dev;
+	int max_depth;
+
+	if (queue_depth < 1)
+		return sdev->queue_depth;
+
+	dev = ata_scsi_find_dev(ap, sdev);
+	if (!dev || !ata_dev_enabled(dev))
+		return sdev->queue_depth;
+
+	max_depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
+	max_depth = min(ATA_MAX_QUEUE - 1, max_depth);
+	if (queue_depth > max_depth)
+		queue_depth = max_depth;
+
+	scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, queue_depth);
+	return queue_depth;
+}
+
+/**
  *	ata_scsi_start_stop_xlat - Translate SCSI START STOP UNIT command
  *	@qc: Storage for translated ATA taskfile
  *	@scsicmd: SCSI command to translate