From: Hans de Goede <hdegoede@redhat.com>
Date: Tue, 12 Apr 2016 10:27:08 +0000 (+0200)
Subject: USB: uas: Limit qdepth at the scsi-host level
X-Git-Tag: v4.5.2~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=39f0cd2c3f4fced06b50f1451250c3b38c16b0ed;p=thirdparty%2Fkernel%2Fstable.git

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

commit 198de51dbc3454d95b015ca0a055b673f85f01bb upstream.

Commit 64d513ac31bd ("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
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
index c90a7e46cc7bf..8005f9af913c2 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -800,7 +800,6 @@ 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;
 }
 
@@ -932,6 +931,12 @@ 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)