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From:   Alexander Kappner <agk@godking.net>
To:     stern@rowland.harvard.edu, oneukum@suse.com
Cc:     linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        usb-storage@lists.one-eyed-alien.net, gregkh@linuxfoundation.org,
        Alexander Kappner <agk@godking.net>
Subject: [PATCH v2 1/2] [usb-storage] Add support for FL_ALWAYS_SYNC flag in the UAS driver
Date:   Fri, 18 May 2018 21:50:15 -0700
Message-Id: <1526705416-12573-2-git-send-email-agk@godking.net>
In-Reply-To: <1526705416-12573-1-git-send-email-agk@godking.net>
References: <Pine.LNX.4.44L0.1805181634000.1645-100000@iolanthe.rowland.org>
 <1526705416-12573-1-git-send-email-agk@godking.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 6034c39..9e9de54 100644
--- 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;
 }
-- 
2.1.4