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Date:   Thu, 25 Feb 2021 00:43:58 +0200
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Geert Uytterhoeven <geert+renesas@glider.be>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: dsa: sja1105: Remove unneeded cast in
 sja1105_crc32()
Message-ID: <20210224224358.pysql5pu23zt7mtb@skbuf>
References: <20210223112003.2223332-1-geert+renesas@glider.be>
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On Tue, Feb 23, 2021 at 12:20:03PM +0100, Geert Uytterhoeven wrote:
> sja1105_unpack() takes a "const void *buf" as its first parameter, so
> there is no need to cast away the "const" of the "buf" variable before
> calling it.
> 
> Drop the cast, as it prevents the compiler performing some checks.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

By the way, your email went straight to my spam box, I just found the
patch by mistake on patchwork.

    Why is this message in spam?
    It is in violation of Google's recommended email sender guidelines.

> Compile-tested only.
> 
> BTW, sja1105_packing() and packing() are really bad APIs, as the input
> pointer parameters cannot be const due to the direction depending on
> "op".  This means the compiler cannot do const checks.  Worse, callers
> are required to cast away constness to prevent the compiler from
> issueing warnings.  Please don't do this!
> ---

What const checks can the compiler not do?
Also, if you know of an existing kernel API which can replace packing(),
I'm all ears.