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Date:   Sat, 22 Aug 2020 01:57:53 +0300
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Nathan Chancellor <natechancellor@gmail.com>
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>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: Re: [PATCH] net: dsa: sja1105: Do not use address of compatible
 member in sja1105_check_device_id
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References: <20200821222515.414167-1-natechancellor@gmail.com>
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On Fri, Aug 21, 2020 at 03:25:16PM -0700, Nathan Chancellor wrote:
> Clang warns:
> 
> drivers/net/dsa/sja1105/sja1105_main.c:3418:38: warning: address of
> array 'match->compatible' will always evaluate to 'true'
> [-Wpointer-bool-conversion]
>         for (match = sja1105_dt_ids; match->compatible; match++) {
>         ~~~                          ~~~~~~~^~~~~~~~~~
> 1 warning generated.
> 
> We should check the value of the first character in compatible to see if
> it is empty or not. This matches how the rest of the tree iterates over
> IDs.
> 
> Fixes: 0b0e299720bb ("net: dsa: sja1105: use detected device id instead of DT one on mismatch")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1139
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  drivers/net/dsa/sja1105/sja1105_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
> index c3f6f124e5f0..5a28dfb36ec3 100644
> --- a/drivers/net/dsa/sja1105/sja1105_main.c
> +++ b/drivers/net/dsa/sja1105/sja1105_main.c
> @@ -3415,7 +3415,7 @@ static int sja1105_check_device_id(struct sja1105_private *priv)
>  
>  	sja1105_unpack(prod_id, &part_no, 19, 4, SJA1105_SIZE_DEVICE_ID);
>  
> -	for (match = sja1105_dt_ids; match->compatible; match++) {
> +	for (match = sja1105_dt_ids; match->compatible[0]; match++) {
>  		const struct sja1105_info *info = match->data;
>  
>  		/* Is what's been probed in our match table at all? */
> 
> base-commit: 4af7b32f84aa4cd60e39b355bc8a1eab6cd8d8a4
> -- 
> 2.28.0
> 

Thanks, Nathan.

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

-Vladimir