linux-kernel - Re: [PATCH 1/1 net-next] wireless: remove unnecessary sizeof(u8)

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Message-ID: <20141117133618.GC3511@tuxdriver.com>
Date:	Mon, 17 Nov 2014 08:36:19 -0500
From:	"John W. Linville" <linville@...driver.com>
To:	Fabian Frederick <fabf@...net.be>
Cc:	Julian Calaby <julian.calaby@...il.com>,
	Johannes Berg <johannes.berg@...el.com>,
	linux-wireless <linux-wireless@...r.kernel.org>,
	Larry Finger <Larry.Finger@...inger.net>,
	Chaoming Li <chaoming_li@...lsil.com.cn>,
	netdev <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
	b43-dev <b43-dev@...ts.infradead.org>,
	Stefano Brivio <stefano.brivio@...imi.it>,
	Intel Linux Wireless <ilw@...ux.intel.com>
Subject: Re: [PATCH 1/1 net-next] wireless: remove unnecessary sizeof(u8)

On Mon, Nov 17, 2014 at 06:56:27AM +0100, Fabian Frederick wrote:
> 
> 
> > On 16 November 2014 at 23:33 Julian Calaby <julian.calaby@...il.com> wrote:
> >
> >
> > Hi Fabian,
> >
> > On Sat, Nov 15, 2014 at 7:55 AM, Fabian Frederick <fabf@...net.be> wrote:
> > > sizeof(u8) is always 1.
> >
> > I thought that sizeof(*variable) was preferred over sizeof(type), so
> > shouldn't these be switched to that format instead?
> >
> > (I know that this is all no-op, but it should reduce the potential for
> > highly unlikely bugs in the future. Also, the extra processing is
> > compile-time not run-time.)
> >
> > Thanks,
> 
> Hi Julian,
> 
> Of course but char/u8/s8... allocations never use it and result would be the
> same:
> factor 1 multiplication.
> 
> Those rare occurrences (+- 30 in the whole kernel) where we have
> sizeof(u8/s8) is ambiguous.
> 
> Having a patch removing it gives a pointer...
> If the developer meant something else, he will be able to fix it.
> 
> Regards,
> Fabian

sizeof(*variable) still seems safer.  Are the compilers unable to
optimize-away a "multiply by one"?

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@...driver.com			might be all we have.  Be ready.
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