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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 12 Jun 2019 16:14:26 -0700
Message-ID: <CAKwvOdkAJcOCGvveBYaDD2kf4vx7m=b+Nxyn3_n=9aCBapzDcw@mail.gmail.com>
Subject: Re: [PATCH] dmaengine: mv_xor_v2: Fix -Wshift-negative-value
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     Dan Williams <dan.j.williams@intel.com>, vkoul@kernel.org,
        dmaengine@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Wed, Jun 12, 2019 at 3:54 PM 'Nathan Huckleberry' via Clang Built
Linux <clang-built-linux@googlegroups.com> wrote:
> Upon further investigation MV_XOR_V2_DMA_IMSG_THRD_SHIFT and
> MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT are both 0. Since shifting by 0 does
> nothing, these variables can be removed.
>
> Cc: clang-built-linux@googlegroups.com
> Link: https://github.com/ClangBuiltLinux/linux/issues/521
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>
> ---
>  drivers/dma/mv_xor_v2.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c
> index fa5dab481203..5d2e0d1f3ec9 100644
> --- a/drivers/dma/mv_xor_v2.c
> +++ b/drivers/dma/mv_xor_v2.c
> @@ -261,16 +259,15 @@ void mv_xor_v2_enable_imsg_thrd(struct mv_xor_v2_device *xor_dev)
>
>         /* Configure threshold of number of descriptors, and enable timer */
>         reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
> -       reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << MV_XOR_V2_DMA_IMSG_THRD_SHIFT);
> -       reg |= (MV_XOR_V2_DONE_IMSG_THRD << MV_XOR_V2_DMA_IMSG_THRD_SHIFT);
> +       reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK);
> +       reg |= (MV_XOR_V2_DONE_IMSG_THRD);
>         reg |= MV_XOR_V2_DMA_IMSG_TIMER_EN;
>         writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
>
>         /* Configure Timer Threshold */
>         reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT);
> -       reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK <<
> -               MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT);
> -       reg |= (MV_XOR_V2_TIMER_THRD << MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT);
> +       reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK);
> +       reg |= (MV_XOR_V2_TIMER_THRD);

Don't need the parentheses anymore. Please send a v2.

-- 
Thanks,
~Nick Desaulniers