netdev - Re: [PATCH] cxgb4: fix invalid checks in alloc_uld

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Date:   Tue, 23 Aug 2016 13:38:59 +0530
From:   Hariprasad Shenai <hariprasad@...lsio.com>
To:     Andrzej Hajda <a.hajda@...sung.com>
Cc:     "open list:CXGB4 ETHERNET DRIVER (CXGB4)" <netdev@...r.kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cxgb4: fix invalid checks in alloc_uld_rxqs

On Tuesday, August 08/23/16, 2016 at 10:01:59 +0200, Andrzej Hajda wrote:
> On 08/23/2016 09:46 AM, Hariprasad Shenai wrote:
> > On Tuesday, August 08/23/16, 2016 at 08:16:19 +0200, Andrzej Hajda wrote:
> >> Local variable msi_idx defined as unsigned int is always >= 0, thus both
> >> 'if' checks are always true. On the other side presence of USING_MSIX flag
> >> suggests the checks should not be trivially true.
> >> The simplest solution is to replace incorrect checks with direct testing
> >> of adap->flags and remove spare variables.
> >>
> >> The problem has been detected using semantic patch
> >> scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci
> >>
> > The correct fix is to have local variable 'msi_idx' as int instead of unsigned
> > int. Thanks for reporting the issue. Do you want me to send a V2?
> >
> > Thanks,
> > Hari
> >
> >
> If adap->flags is constant during the call I see no point in creating
> separate
> 
> variable with complicated initialization used only for the same thing as
> 
> 'adap->flags & USING_MSIX', and even if adap->flags changes during the call
> 
> much simpler would be to use local var:
> 
>     int using_msix = adap->flags & USING_MSIX;
> 
> and later use tests:
> 
>     if (using_msix)
> 
>         ...
> 
> Am I correct?
Yes, you are correct.