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Date:   Thu, 25 Aug 2022 09:36:02 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     cgel.zte@gmail.com
Cc:     Larry.Finger@lwfinger.net, phil@philpotter.co.uk,
        paskripkin@gmail.com, gregkh@linuxfoundation.org,
        straube.linux@gmail.com, martin@kaiser.cx, jhpark1013@gmail.com,
        makvihas@gmail.com, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org, Minghao Chi <chi.minghao@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>
Subject: Re: [PATCH] staging: r8188eu: remove unnecessary null check
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References: <20220824080350.221614-1-chi.minghao@zte.com.cn>
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On Wed, Aug 24, 2022 at 08:03:50AM +0000, cgel.zte@gmail.com wrote:
> From: Minghao Chi <chi.minghao@zte.com.cn>
> 
> container_of is never null, so this null check is
> unnecessary.
> 

I can't Ack a patch with this commit message because container_of()
*CAN* be NULL.  Here, it requires two things:
1) That ->list is the first struct member of struct wlan_network which
   is true.
2) That "pmlmepriv->pscanned" is NULL.  Which I have not looked at.

It's really ugly to check container_of() for NULL but some people do it
deliberately.  Some people also will add a build time assert to ensure
that ->list is always the first element so that the check always works.

regards,
dan carpenter