Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: drivers/block/ub.c | Date | Sat, 26 Jun 2004 23:56:49 +0200 |
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Am Samstag, 26. Juni 2004 23:41 schrieb David S. Miller: > 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.
Unless I am mistaken, this structure is transfered as such over the bus, so IMHO here it is needed.
Regards Oliver - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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