linux-kernel - RE: [PATCH] mei: Drop unnecessary NULL check after container

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Message-ID: <42c7b18dae6648d69346cc6b77e92178@intel.com>
Date:   Tue, 11 May 2021 05:16:41 +0000
From:   "Winkler, Tomas" <tomas.winkler@...el.com>
To:     Guenter Roeck <linux@...ck-us.net>
CC:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] mei: Drop unnecessary NULL check after container_of



> 
> The result of container_of() operations is never NULL unless the embedded
> element is the first element of the data structure, which is not the case here.
> The NULL check is therefore unnecessary and misleading. Remove it.
> 
> This change was made automatically with the following Coccinelle script.
> 
> @@
> type t;
> identifier v;
> statement s;
> @@
> 
> <+...
> (
>   t v = container_of(...);
> |
>   v = container_of(...);
> )
>   ...
>   when != v
> - if (\( !v \| v == NULL \) ) s
> ...+>
> 
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Acked-by: Tomas Winkler <tomas.winkler@...el.com>
> ---
>  drivers/misc/mei/main.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c index
> 28937b6e7e0c..9001c45f6fc4 100644
> --- a/drivers/misc/mei/main.c
> +++ b/drivers/misc/mei/main.c
> @@ -50,8 +50,6 @@ static int mei_open(struct inode *inode, struct file *file)
>  	int err;
> 
>  	dev = container_of(inode->i_cdev, struct mei_device, cdev);
> -	if (!dev)
> -		return -ENODEV;
> 
>  	mutex_lock(&dev->device_lock);
> 
> --
> 2.25.1