On Mon, 9 Feb 2015, Oliver Neukum wrote:
> 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 devices. For them
> it is necessary to simply believe the class specific
> command and report its result back to the SCSI layer.
>
> Signed-off-by: Oliver Neukum <oneukum@xxxxxxx>
> ---
> drivers/usb/storage/usb.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
> index d468d02..cf2fafb 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)
>= 8, not > 8. Or, if you prefer, > 7.
> + us_to_host(us)->max_lun = us->max_lun+1;
What about the fact that you may be overriding max_scsi_luns?
Also, since the protocol allows only 4 bits for the LUN value, would it
be safer to use min(us->max_lun+1, 16)?
Alan Stern
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