Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38;
Date:   Tue, 12 Dec 2023 11:23:44 +0000
From:   Simon Horman <horms@kernel.org>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        kernel test robot <lkp@intel.com>
Subject: Re: [PATCH net-next v1 1/1] net: dl2k: Use proper conversion of
 dev_addr before IO to device
Message-ID: <20231212112344.GZ5817@kernel.org>
References: <20231208153327.3306798-1-andriy.shevchenko@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231208153327.3306798-1-andriy.shevchenko@linux.intel.com>
Precedence: bulk

On Fri, Dec 08, 2023 at 05:33:27PM +0200, Andy Shevchenko wrote:
> The driver is using iowriteXX()/ioreadXX() APIs which are LE IO
> accessors simplified as
> 
>   1. Convert given value _from_ CPU _to_ LE
>   2. Write it to the device as is
> 
> The dev_addr is a byte stream, but because the driver uses 16-bit
> IO accessors, it wants to perform double conversion on BE CPUs,
> but it took it wrong, as it effectivelly does two times _from_ CPU
> _to_ LE. What it has to do is to consider dev_addr as an array of
> LE16 and hence do _from_ LE _to_ CPU conversion, followed by implied
> _from_ CPU _to_ LE in the iowrite16().
> 
> To achieve that, use get_unaligned_le16(). This will make it correct
> and allows to avoid sparse warning as reported by LKP.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202312030058.hfZPTXd7-lkp@intel.com/
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Thanks Andy,

I agree with your reasoning that the explicit conversion is reversed.

Reviewed-by: Simon Horman <horms@kernel.org>