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Subject: Re: [PATCH] b43: shut up clang -Wuninitialized variable warning
From:   Kalle Valo <kvalo@codeaurora.org>
In-Reply-To: <20190322143725.1332353-1-arnd@arndb.de>
References: <20190322143725.1332353-1-arnd@arndb.de>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Larry Finger <Larry.Finger@lwfinger.net>,
        Arnd Bergmann <arnd@arndb.de>, Priit Laes <plaes@plaes.org>,
        clang-built-linux@googlegroups.com,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <natechancellor@gmail.com>,
        linux-wireless@vger.kernel.org, b43-dev@lists.infradead.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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Message-Id: <20190404101423.7C6CF61C62@smtp.codeaurora.org>
Date:   Thu,  4 Apr 2019 10:14:22 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
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Arnd Bergmann <arnd@arndb.de> wrote:

> Clang warns about what is clearly a case of passing an uninitalized
> variable into a static function:
> 
> drivers/net/wireless/broadcom/b43/phy_lp.c:1852:23: error: variable 'gains' is uninitialized when used here
>       [-Werror,-Wuninitialized]
>                 lpphy_papd_cal(dev, gains, 0, 1, 30);
>                                     ^~~~~
> drivers/net/wireless/broadcom/b43/phy_lp.c:1838:2: note: variable 'gains' is declared here
>         struct lpphy_tx_gains gains, oldgains;
>         ^
> 1 error generated.
> 
> However, this function is empty, and its arguments are never evaluated,
> so gcc in contrast does not warn here. Both compilers behave in a
> reasonable way as far as I can tell, so we should change the code
> to avoid the warning everywhere.
> 
> We could just eliminate the lpphy_papd_cal() function entirely,
> given that it has had the TODO comment in it for 10 years now
> and is rather unlikely to ever get done. I'm doing a simpler
> change here, and just pass the 'oldgains' variable in that has
> been initialized, based on the guess that this is what was
> originally meant.
> 
> Fixes: 2c0d6100da3e ("b43: LP-PHY: Begin implementing calibration & software RFKILL support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

Patch applied to wireless-drivers-next.git, thanks.

d825db346270 b43: shut up clang -Wuninitialized variable warning

-- 
https://patchwork.kernel.org/patch/10865933/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches