usb-storage: support for more than 8 LUNs

This is necessary to make some storage arrays work.

Some storage devices have more than 8 LUNs. In addition
you can hook up a WideSCSI bus to USB. In these cases even
level 2 devices can have more than 8 LUNs. For them
it is necessary to simply believe the class specific
command and report its result back to the SCSI layer.

Off by one Alan noticed is fixed.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index d468d02179f4..5600c33fcadb 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -889,6 +889,12 @@ static void usb_stor_scan_dwork(struct work_struct *work)
             !(us->fflags & US_FL_SCM_MULT_TARG)) {
                 mutex_lock(&us->dev_mutex);
                 us->max_lun = usb_stor_Bulk_max_lun(us);
+                /*
+                 * Allow proper scanning of devices that present more than 8 LUNs
+                 * While not affecting other devices that may need the previous behavior
+                 */
+                if (us->max_lun >= 8)
+                        us_to_host(us)->max_lun = us->max_lun+1;
                 mutex_unlock(&us->dev_mutex);
         }
         scsi_scan_host(us_to_host(us));