Subject: Re: [PATCH][MIPS][7/7] AR7: ethernet

From: Thiemo Seufer <[email-masked]>
Date: Thu, 13 Sep 2007 02:42:46 +0100

Ralf Baechle wrote:
> On Sat, Sep 08, 2007 at 02:23:00AM +0200, Matteo Croce wrote:
[snip]
> > +/* Register definitions */
> > +struct cpmac_control_regs {
> > +	u32 revision;
> > +	u32 control;
> > +	u32 teardown;
> > +	u32 unused;
> > +} __attribute__ ((packed));
> > +
> > +struct cpmac_int_regs {
> > +	u32 stat_raw;
> > +	u32 stat_masked;
> > +	u32 enable;
> > +	u32 clear;
> > +} __attribute__ ((packed));
> > +
> > +struct cpmac_stats {
> > +	u32 good;
> > +	u32 bcast;
> > +	u32 mcast;
> > +	u32 pause;
> > +	u32 crc_error;
> > +	u32 align_error;
> > +	u32 oversized;
> > +	u32 jabber;
> > +	u32 undersized;
> > +	u32 fragment;
> > +	u32 filtered;
> > +	u32 qos_filtered;
> > +	u32 octets;
> > +} __attribute__ ((packed));
> 
> All struct members here are sized such that there is no padding needed, so
> the packed attribute doesn't buy you anything - unless of course the
> entire structure is missaligned but I don't see how that would be possible
> in this driver so the __attribute__ ((packed)) should go - it result in
> somwhat larger and slower code.

FWIW, a modern gcc will warn about such superfluous packed attributes,
that's another reason to remove those.

Thiemo