linux-kernel - Re: [PATCH net-next v6 02/25] net: dsa: qca8k: use iopoll macro for qca8k_busy

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Message-ID: <20210514225225.GI12395@shell.armlinux.org.uk>
Date:   Fri, 14 May 2021 23:52:25 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Ansuel Smith <ansuelsmth@...il.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Heiner Kallweit <hkallweit1@...il.com>, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v6 02/25] net: dsa: qca8k: use iopoll macro for
 qca8k_busy_wait

On Fri, May 14, 2021 at 10:59:52PM +0200, Ansuel Smith wrote:
> Use iopoll macro instead of while loop.
> 
> Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>
> Reviewed-by: Andrew Lunn <andrew@...n.ch>

This doesn't look quite right to me.

>  static int
>  qca8k_busy_wait(struct qca8k_priv *priv, u32 reg, u32 mask)
>  {
> -	unsigned long timeout;
> -
> -	timeout = jiffies + msecs_to_jiffies(20);
> +	u32 val;

val is unsigned here.

> +	/* Check if qca8k_read has failed for a different reason
> +	 * before returning -ETIMEDOUT
> +	 */
> +	if (ret < 0 && val < 0)

but here you are checking it for a negative number - this will always be
false, making the conditional code unreachable. Either the test is wrong,
or the type of val is wrong. Please resolve.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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