Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20200116222658.5285-1-natechancellor@gmail.com>
In-Reply-To: <20200116222658.5285-1-natechancellor@gmail.com>
From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Thu, 16 Jan 2020 14:43:39 -0800
Message-ID: <CAKwvOdmFbojiubviQYqwJLLpCLky_bpOH4jYjy4WCbOinPRYuA@mail.gmail.com>
Subject: Re: [PATCH] IB/hfi1: Fix logical condition in msix_request_irq
To:     Nathan Chancellor <natechancellor@gmail.com>
Cc:     Mike Marciniszyn <mike.marciniszyn@intel.com>,
        Dennis Dalessandro <dennis.dalessandro@intel.com>,
        Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>, linux-rdma@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Jan 16, 2020 at 2:27 PM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> Clang warns:
>
> drivers/infiniband/hw/hfi1/msix.c:136:22: warning: overlapping
> comparisons always evaluate to false [-Wtautological-overlap-compare]
>         if (type < IRQ_SDMA && type >= IRQ_OTHER)
>             ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
> 1 warning generated.
>
> It is impossible for something to be less than 0 (IRQ_SDMA) and greater
> than or equal to 3 (IRQ_OTHER) at the same time. A logical OR should
> have been used to keep the same logic as before.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/841
> Fixes: 13d2a8384bd9 ("IB/hfi1: Decouple IRQ name from type")
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Thanks for the patch. LGTM.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  drivers/infiniband/hw/hfi1/msix.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/hw/hfi1/msix.c b/drivers/infiniband/hw/hfi1/msix.c
> index 4a620cf80588..db82db497b2c 100644
> --- a/drivers/infiniband/hw/hfi1/msix.c
> +++ b/drivers/infiniband/hw/hfi1/msix.c
> @@ -133,7 +133,7 @@ static int msix_request_irq(struct hfi1_devdata *dd, void *arg,
>         if (nr == dd->msix_info.max_requested)
>                 return -ENOSPC;
>
> -       if (type < IRQ_SDMA && type >= IRQ_OTHER)
> +       if (type < IRQ_SDMA || type >= IRQ_OTHER)

-- 
Thanks,
~Nick Desaulniers