usb-storage: Add support for FL_ALWAYS_SYNC flag in the UAS driver

BugLink: http://bugs.launchpad.net/bugs/1790188
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@godking.net>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 6034c39b67d14ab43376b87eabbbc8e5bf87e0b1..9e9de5452860d39c2a6da87546459a38086b21b9 100644 (file)
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -836,6 +836,12 @@ static int uas_slave_configure(struct scsi_device *sdev)
        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;
 }