Re: drivers/block/ub.c

["David S. Miller" <davem@redhat.com>]

On Sat, 26 Jun 2004 22:35:15 +0200
Oliver Neukum <oliver@neukum.org> wrote:

> 
> > +/* command block wrapper */
> > +struct bulk_cb_wrap {
> > +	u32	Signature;		/* contains 'USBC' */
> > +	u32	Tag;			/* unique per command id */
> > +	u32	DataTransferLength;	/* size of data */
> > +	u8	Flags;			/* direction in bit 0 */
> > +	u8	Lun;			/* LUN normally 0 */
> > +	u8	Length;			/* of of the CDB */
> > +	u8	CDB[MAX_CDB_SIZE];	/* max command */
> > +};
> 
> should be packed attributed

Only when necessary, and I do not belive any platform Linux supports
needs it in this case.

Packed attributing is _BAD_ when it isn't needed because it forces GCC
to output multiple byte-sized loads in order to access larger than
byte-sized elements because it cannot assume the proper alignment on RISC
systems.