linux-kernel - Re: [PATCH 8/8] staging: rtl8188eu: use is_broadcast_ether

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Message-ID: <12e1804800e490aa57b51a0e64c6da573d32a3a4.camel@perches.com>
Date:   Sun, 29 Jul 2018 10:59:51 -0700
From:   Joe Perches <joe@...ches.com>
To:     Michael Straube <straube.linux@...il.com>,
        gregkh@...uxfoundation.org
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 8/8] staging: rtl8188eu: use is_broadcast_ether_addr

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.