[PATCH 4.9 16/30] usb-storage: Add support for FL_ALWAYS_SYNC flag in the UAS driver

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Kappner <agk@xxxxxxxxxxx>

commit 8c4e97ddfe73a0958bb0abf7e6a3bc4cc3e04936 upstream.

The ALWAYS_SYNC flag is currently honored by the usb-storage driver but not UAS
and is required to work around devices that become unstable upon being
queried for cache. This code is taken straight from:
drivers/usb/storage/scsiglue.c:284

Signed-off-by: Alexander Kappner <agk@xxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Acked-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/storage/uas.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -836,6 +836,12 @@ static int uas_slave_configure(struct sc
 	if (devinfo->flags & US_FL_BROKEN_FUA)
 		sdev->broken_fua = 1;
 
+	/* UAS also needs to support FL_ALWAYS_SYNC */
+	if (devinfo->flags & US_FL_ALWAYS_SYNC) {
+		sdev->skip_ms_page_3f = 1;
+		sdev->skip_ms_page_8 = 1;
+		sdev->wce_default_on = 1;
+	}
 	scsi_change_queue_depth(sdev, devinfo->qdepth - 2);
 	return 0;
 }