linux-kernel - Re: [RFC PATCH] usb: gadget: Drop unnecessary NULL checks after container

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Message-ID: <87v98ckt2w.fsf@kernel.org>
Date:   Sat, 24 Apr 2021 11:03:19 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Guenter Roeck <linux@...ck-us.net>, linux-usb@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [RFC PATCH] usb: gadget: Drop unnecessary NULL checks after
 container_of


Hi Guenter,

Guenter Roeck <linux@...ck-us.net> writes:
> The parameters passed to allow_link and drop_link functions are never NULL.
> That means the result of container_of() on those parameters is also
> never NULL, even if the reference into the structure points to the first
> element of the structure. Remove the subsequent NULL checks.
>
> The changes in this patch were made automatically using the following
> Coccinelle script.
>
> @@
> type t;
> identifier v;
> statement s;
> @@
>
> <+...
> (
>   t v = container_of(...);
> |
>   v = container_of(...);
> )
>   ...
>   when != v
> - if (\( !v \| v == NULL \) ) s
> ...+>
>
> Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Cc: Felipe Balbi <balbi@...nel.org>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
> ---
> After the recent discussion about a patch which tried to add a check
> against NULL after container_of(), I realized that there are a number
> of such checks in the kernel.
>
> Now the big question: Are patches like this acceptable, or do they count
> as noise ?

Not noise in my book :-)

Acked-by: Felipe Balbi <balbi@...nel.org>

-- 
balbi

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