SCSI & usb-storage: add flags for VPD pages and REPORT LUNS

This patch (as1507) adds a skip_vpd_pages flag to struct scsi_device
and a no_report_luns flag to struct scsi_target.  The first is used to
control whether sd will look at VPD pages for information on block
provisioning, limits, and characteristics.  The second prevents
scsi_report_lun_scan() from issuing a REPORT LUNS command.

The patch also modifies usb-storage to set the new flag bits for all
USB devices and targets, and to stop adjusting the scsi_level value.

Historically we have seen that USB mass-storage devices often don't
support VPD pages or REPORT LUNS properly.  Until now we have avoided
these things by setting the scsi_level to SCSI_2 for all USB devices.
But this has the side effect of storing the LUN bits into the second
byte of each CDB, and now we have a report of a device which doesn't
like that.  The best solution is to stop abusing scsi_level and
instead have separate flags for VPD pages and REPORT LUNS.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Perry Wagle <wagle@mac.com>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 16 insertions, 10 deletions

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 13b8bcdf3dbafd..dc68cc9fef5d9c 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -197,6 +197,9 @@ static int slave_configure(struct scsi_device *sdev)
 		 * page x08, so we will skip it. */
 		sdev->skip_ms_page_8 = 1;
 
+		/* Some devices don't handle VPD pages correctly */
+		sdev->skip_vpd_pages = 1;
+
 		/* Some disks return the total number of blocks in response
 		 * to READ CAPACITY rather than the highest block number.
 		 * If this device makes that mistake, tell the sd driver. */
@@ -217,16 +220,6 @@ static int slave_configure(struct scsi_device *sdev)
 		if (sdev->scsi_level > SCSI_SPC_2)
 			us->fflags |= US_FL_SANE_SENSE;
 
-		/* Some devices report a SCSI revision level above 2 but are
-		 * unable to handle the REPORT LUNS command (for which
-		 * support is mandatory at level 3).  Since we already have
-		 * a Get-Max-LUN request, we won't lose much by setting the
-		 * revision level down to 2.  The only devices that would be
-		 * affected are those with sparse LUNs. */
-		if (sdev->scsi_level > SCSI_2)
-			sdev->sdev_target->scsi_level =
-					sdev->scsi_level = SCSI_2;
-
 		/* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
 		 * Hardware Error) when any low-level error occurs,
 		 * recoverable or not.  Setting this flag tells the SCSI
@@ -283,6 +276,18 @@ static int slave_configure(struct scsi_device *sdev)
 	return 0;
 }
 
+static int target_alloc(struct scsi_target *starget)
+{
+	/*
+	 * Some USB drives don't support REPORT LUNS, even though they
+	 * report a SCSI revision level above 2.  Tell the SCSI layer
+	 * not to issue that command; it will perform a normal sequential
+	 * scan instead.
+	 */
+	starget->no_report_luns = 1;
+	return 0;
+}
+
 /* queue a command */
 /* This is always called with scsi_lock(host) held */
 static int queuecommand_lck(struct scsi_cmnd *srb,
@@ -546,6 +551,7 @@ struct scsi_host_template usb_stor_host_template = {
 
 	.slave_alloc =			slave_alloc,
 	.slave_configure =		slave_configure,
+	.target_alloc =			target_alloc,
 
 	/* lots of sg segments can be handled */
 	.sg_tablesize =			SCSI_MAX_SG_CHAIN_SEGMENTS,