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

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
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
index 13e4cc31bc79e61a11539c42b8ea182b3dd6b3af..b1ec7499166d97202b257640ae68b1a0f941df91 100644 (file)
--- 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)