[PATCH 2/2] Drivers: scsi: storvsc: Don't pass ATA_16 command to the host

["K. Y. Srinivasan" <kys@microsoft.com>]

The current Windows hosts don't handle the ATA_16 command and furthermore
return a generic error code after filtering the command on the host side.
For now filter the command on the guest side until the host is modified to
properly handle unsupported commands.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/scsi/storvsc_drv.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 8b967c9..783bab8 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1229,8 +1229,17 @@ static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
 	/*
 	 * smartd sends this command and the host does not handle
 	 * this. So, don't send it.
+	 * The current Windows hosts implement a subset of scsi commands
+	 * and for the commands that are not implemented, the host filters
+	 * them and returns a generic failure SRB status. I have been in
+	 * discussions with the Windows team to return the appropriate SRB
+	 * status code for unsupported scsi commands and while they have
+	 * agreed to implement this, it is not clear when this change will be
+	 * available. Consequently, filtering the command before submitting it
+	 * to the host is a resonable interim solution.
 	 */
 	case SET_WINDOW:
+	case ATA_16:
 		scmnd->result = ILLEGAL_REQUEST << 16;
 		allowed = false;
 		break;
-- 
1.7.4.1