[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