From: Jens Axboe <jens.axboe@oracle.com>
Date: Mon, 27 Oct 2008 18:23:06 +0000 (+0100)
Subject: libata: fix NCQ devices behind port multipliers
X-Git-Tag: v2.6.28-rc3~94^2
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=43a49cbdf31e812c0d8f553d433b09b421f5d52c;p=linux-2.6-omap-h63xx.git

libata: fix NCQ devices behind port multipliers

For devices behind sata port multipliers, we have to make sure that
they share a tag map since all tags for that PMP must be unique.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 4b95c4387e9..bbb30d882f0 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1107,6 +1107,15 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
 
 		depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
 		depth = min(ATA_MAX_QUEUE - 1, depth);
+
+		/*
+		 * If this device is behind a port multiplier, we have
+		 * to share the tag map between all devices on that PMP.
+		 * Set up the shared tag map here and we get automatic.
+		 */
+		if (dev->link->ap->pmp_link)
+			scsi_init_shared_tag_map(sdev->host, ATA_MAX_QUEUE - 1);
+
 		scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);
 		scsi_activate_tcq(sdev, depth);
 	}