James Bottomley wrote:
> If you're doing this:
> 
> On Thu, 2003-05-15 at 18:50, Douglas Gilbert wrote:
> 
>>+#define scsi_status(result) ((result) & 0x7e)
> 
> 
> because bit0 is reserved in SCSI-2, then it should be 0x3e because bits
> 6 and 7 are also reserved.  Of course, this would clash with the SCSI-3
> definition of TASK ABORTED, sigh.
> 
> Perhaps it's better just not to bother with the mask?

James,
The macro still gets rid of the upper bytes in
scsi_cmnd::result so in needs to be at least
a mask of 0xff.

With a mask of 0x7e it is correct for SCSI-3,
bit 6 is reserved ** in SCSI-2  and "vendor unique"
in SCSI-1 and SCSI_1_CCS. I dug up a SCSI 1 draft and
the Status byte table is attached. So as far as I
can see our only exposure is to SCSI 1 and CCS
devices.

A possible source of confusion with this proposed
patch is that 'scsi_status' is probably one of the
most common variable names in the SCSI subsystem.
As a macro it shouldn't clash but it may confuse.
Alternate patch using get_scsi_status() attached.


** SCSI-2 defines reserved as "set aside for future
standardization" but SPC-3 (spc3r12) nails it down:
"A reserved bit, byte, word or field shall be set to
zero, ...".

Doug Gilbert