linux-kernel - Re: [PATCH net-next v3] net: ipa: Remove redundant comparison with zero

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Message-ID: <CA+uqrQCChwyE--PDxvrGMnfk9W1Nf0C4kS9fW0Ozmx-mQpyH8w@mail.gmail.com>
Date:   Sat, 17 Dec 2022 06:39:42 +0900
From:   Kang Minchul <tegongkang@...il.com>
To:     Alex Elder <elder@...e.org>
Cc:     Alex Elder <elder@...nel.org>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v3] net: ipa: Remove redundant comparison with zero

2022년 12월 17일 (토) 오전 6:34, Alex Elder <elder@...e.org>님이 작성:
>
> On 12/16/22 3:11 PM, Kang Minchul wrote:
> > platform_get_irq_byname() returns non-zero IRQ number on success,
> > and negative error number on failure.
> >
> > So comparing return value with zero is unnecessary.
> >
> > Signed-off-by: Kang Minchul <tegongkang@...il.com>
> > ---
> >   drivers/net/ipa/gsi.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
> > index bea2da1c4c51..e05e94bd9ba0 100644
> > --- a/drivers/net/ipa/gsi.c
> > +++ b/drivers/net/ipa/gsi.c
> > @@ -1302,7 +1302,7 @@ static int gsi_irq_init(struct gsi *gsi, struct platform_device *pdev)
> >       int ret;
> >
> >       ret = platform_get_irq_byname(pdev, "gsi");
> > -     if (ret <= 0)
> > +     if (ret < 0)
> >               return ret ? : -EINVAL;
>
> In doing this, you assume platform_get_irq_byname() never
> returns 0.  I accept that assumption now.  But in that case,
> ret will *always* be non-zero if the branch is taken, so the
> next line should simply be:
>
>                 return ret;
>
> There are two other places in the IPA driver that follow exactly
> the same pattern of getting the IRQ number and handling the
> possibility that the value returned is (erroneously) 0.  If
> you're making this change in one place, please do so in all
> of them.
>
> Frankly though, I think this change adds little value, and I
> would be content to just leave everything as-is...
>
>                                         -Alex
>
> >
> >       gsi->irq = ret;
>

Hmm, yes.
I think you're right.
I don't think this code is worth much either.
Please ignore this patch and leave everything as-is.

Thanks for your feedback though :)

Kang Minchul