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Subject: Re: [PATCH V6 XRT Alveo 08/20] fpga: xrt: driver infrastructure
To:     Tom Rix <trix@redhat.com>, Lizhi Hou <lizhi.hou@xilinx.com>,
        <linux-kernel@vger.kernel.org>
CC:     <linux-fpga@vger.kernel.org>, <maxz@xilinx.com>,
        <sonal.santan@xilinx.com>, <yliu@xilinx.com>,
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        <devicetree@vger.kernel.org>, <mdf@kernel.org>, <robh@kernel.org>,
        Max Zhen <max.zhen@xilinx.com>
References: <20210512015339.5649-1-lizhi.hou@xilinx.com>
 <20210512015339.5649-9-lizhi.hou@xilinx.com>
 <c6ed9349-1a9a-62a9-521f-a12ec8c4a5a5@redhat.com>
From:   Lizhi Hou <lizhi.hou@xilinx.com>
Message-ID: <f0dfe5ee-d4ac-895f-1ba6-136cd897ba08@xilinx.com>
Date:   Wed, 19 May 2021 19:48:17 -0700
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On 05/13/2021 08:27 AM, Tom Rix wrote:
>
> On 5/11/21 6:53 PM, Lizhi Hou wrote:
>> Infrastructure code providing APIs for managing leaf driver instance
>> groups, facilitating inter-leaf driver calls and root calls.
>>
>> Signed-off-by: Sonal Santan <sonal.santan@xilinx.com>
>> Signed-off-by: Max Zhen <max.zhen@xilinx.com>
>> Signed-off-by: Lizhi Hou <lizhi.hou@xilinx.com>
>> Reviewed-by: Tom Rix <trix@redhat.com>
>
>> +
>> +int xrt_subdev_root_request(struct xrt_device *self, u32 cmd, void 
>> *arg)
>> +{
>> +     struct device *dev = DEV(self);
>> +     struct xrt_subdev_platdata *pdata = DEV_PDATA(self);
>> +
>> +     WARN_ON(!pdata->xsp_root_cb);
>> +     return (*pdata->xsp_root_cb)(dev->parent, 
>> pdata->xsp_root_cb_arg, cmd, arg);
>
> I am running v6 through clang's static analyzer.
>
> It reports this problem
>
> drivers/fpga/xrt/lib/subdev.c:72:9: warning: Called function pointer is
> null (null dereference)
>         return (*pdata->xsp_root_cb)(dev->parent,
> pdata->xsp_root_cb_arg, cmd, arg);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Though there is a warn_on, can you also add a
>
> return -EINVAL;
>
> To cover this case?
Sure. I will run through clang myself to check the fix.

Thanks,
Lizhi
>
> Tom
>
>> +}
>