Re: [PATCH 8/8] staging: rtl8188eu: use is_broadcast_ether_addr

[Michael Straube]

On 07/29/18 19:59, Joe Perches wrote:
> On Sun, 2018-07-29 at 19:42 +0200, Michael Straube wrote:
> > On 07/29/18 19:21, Joe Perches wrote:
> > > On Sun, 2018-07-29 at 19:08 +0200, Michael Straube wrote:
> > > > Use is_broadcast_ether_addr instead of checking each byte of the
> > > > address array for 0xff. Shortens the code and improves readability.
> > >
> > > You should show in the commit log that sta_addr is __aligned(2)
> > > as required by is_broadcast_ether_addr, otherwise you could be
> > > introducing runtime alignment defects.
> >
> > Ok, sta_addr is used from following structs.
> >
> > struct ieee_param {
> >           u32 cmd;
> >           u8 sta_addr[ETH_ALEN];
> >           union {
> >           ...
> >           ...
> >           }; u
> > };
> >
> > struct ieee_param_ex {
> > 	u32 cmd;
> > 	u8 sta_addr[ETH_ALEN];
> > 	u8 data[0];
> > };
> >
> > Well, looking at it now, I'm not sure about the alignment anymore
> > in the struct that contains the union. Is sta_addr in the first
> > struct __aligned(2)?
> >
> > Should I include the snippets in the commit message, or is just
> > writing that sta_addr is __aligned(2) enough? (if it is in the
> > first case...)
>
> It's enough to just state that the uses are properly aligned
> as long as you looked and understand that it's required.

Ok, thank you.

I looked at it and understand that it's required.
But, as mentioned, at second look I'm not sure about the union.

I guess I need to read a little more about the alignment of unions.
Any hints are welcomed. :)

Michael