USB: mass storage: emulation of sat scsi_pass_thru with ATACB

I have got a cypress usb-ide bridge and I would like to tune or monitor
my disk with tools like hdparm, hddtemp or smartctl.

My controller support a way to send raw ATA command to the disk with
something call atacb (see
http://download.cypress.com.edgesuite.net/design_resources/datasheets/contents/cy7c68300c_8.pdf).

Atacb support can be added for each application, but there is some disadvantages :
- all application need to be patched
- A race is possible if there other accesses, because the emulation can
be split in 2 atacb scsi transactions. One for sending the command, one
for reading the register (if ck_cond is set). 

I have implemented the emulation in usb-storage with a special proto_handler,
and an unsual entry.

Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/storage/scsiglue.c

@@ -132,7 +132,7 @@ static int slave_configure(struct scsi_device *sdev)
 		/* Disk-type devices use MODE SENSE(6) if the protocol
 		 * (SubClass) is Transparent SCSI, otherwise they use
 		 * MODE SENSE(10). */
-		if (us->subclass != US_SC_SCSI)
+		if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB)
 			sdev->use_10_for_ms = 1;
 
 		/* Many disks only accept MODE SENSE transfer lengths of