USB: uas: Limit qdepth at the scsi-host level

jwrdegoede · gregkh · commit 198de51dbc34 · 2016-04-13T12:02:28.000-07:00
Commit 64d513a ("scsi: use host wide tags by default") causes the SCSI core to queue more commands then we can handle on devices with multiple LUNs, limit the queue depth at the scsi-host level instead of per slave to fix this. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1315013 Cc: stable@vger.kernel.org # 4.4.x and 4.5.x Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
@@ -824,7 +824,6 @@ static int uas_slave_configure(struct scsi_device *sdev)
 	if (devinfo->flags & US_FL_BROKEN_FUA)
 		sdev->broken_fua = 1;
 
-	scsi_change_queue_depth(sdev, devinfo->qdepth - 2);
 	return 0;
 }
 
@@ -956,6 +955,12 @@ static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
 	if (result)
 		goto set_alt0;
 
+	/*
+	 * 1 tag is reserved for untagged commands +
+	 * 1 tag to avoid off by one errors in some bridge firmwares
+	 */
+	shost->can_queue = devinfo->qdepth - 2;
+
 	usb_set_intfdata(intf, shost);
 	result = scsi_add_host(shost, &intf->dev);
 	if (result)
