linux-kernel - Re: [PATCH][mtd-next] mtd: nand: remove redundant check of len

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Date:   Wed, 13 Dec 2017 21:47:38 +0100
From:   Boris Brezillon <boris.brezillon@...e-electrons.com>
To:     Colin Ian King <colin.king@...onical.com>
Cc:     Richard Weinberger <richard@....at>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Cyrille Pitchen <cyrille.pitchen@...ev4u.fr>,
        linux-mtd@...ts.infradead.org, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH][mtd-next] mtd: nand: remove redundant check of len

On Wed, 13 Dec 2017 20:44:45 +0000
Colin Ian King <colin.king@...onical.com> wrote:

> On 13/12/17 20:38, Boris Brezillon wrote:
> > On Wed, 13 Dec 2017 20:30:04 +0000
> > Colin Ian King <colin.king@...onical.com> wrote:
> >   
> >> On 13/12/17 20:24, Boris Brezillon wrote:  
> >>> On Wed, 13 Dec 2017 20:17:43 +0000
> >>> Colin King <colin.king@...onical.com> wrote:
> >>>     
> >>>> From: Colin Ian King <colin.king@...onical.com>
> >>>>
> >>>> The check of len being zero is redundant as it has already been
> >>>> sanity checked for this value at the start of the function. Hence
> >>>> it is impossible for this test to be true and so the redundant
> >>>> code can be removed.    
> >>>
> >>> Nope, it's not the same test, the initial test is
> >>>
> >>> 	if (len && !buf)    
> >>
> >> Ah, the current tip from linux-next has:
> >>
> >> 1912        if (!len || !buf)
> >> 1913                return -EINVAL;
> >>
> >> ..so I guess that's why it got picked up by static analysis.  
> > 
> > Hm, that's weird, that's not what I see [1] in linux-next.  
> 
> I see my mistake, I fixed the *wrong* function, I'll send a v2. Doh.

Yep, just noticed that too. No need to send a patch though.