Re: [PATCH RFC leds + net-next 5/7] net: phy: add simple incrementing phyindex member to phy_device struct

From: Pavel Machek <pavel@ucw.cz>
To: "Marek Behún" <kabel@kernel.org>
Cc: netdev@vger.kernel.org, linux-leds@vger.kernel.org,
	Dan Murphy <dmurphy@ti.com>, Russell King <linux@armlinux.org.uk>,
	Andrew Lunn <andrew@lunn.ch>,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Ben Whitten <ben.whitten@gmail.com>
Subject: Re: [PATCH RFC leds + net-next 5/7] net: phy: add simple incrementing phyindex member to phy_device struct
Date: Mon, 1 Mar 2021 11:46:10 +0100	[thread overview]
Message-ID: <20210301104610.GD31897@duo.ucw.cz> (raw)
In-Reply-To: <20201030114435.20169-6-kabel@kernel.org>

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On Fri 2020-10-30 12:44:33, Marek Behún wrote:
> Add a new integer member phyindex to struct phy_device. This member is
> unique for every phy_device. Atomic incrementation occurs in
> phy_device_register.
> 
> This can be used for example in LED sysfs API. The LED subsystem names
> each LED in format `device:color:function`, but currently the PHY device
> names are not suited for this, since in some situations a PHY device
> name can look like this
>   d0032004.mdio-mii:01
> or even like this
>   !soc!internal-regs@d0000000!mdio@32004!switch0@10!mdio:08
> Clearly this cannot be used as the `device` part of a LED name.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>

Atomic should _not_ be neccessary for this. Just make sure access is
serialised by some existing lock.
								Pavel
								
> @@ -892,6 +893,7 @@ EXPORT_SYMBOL(get_phy_device);
>   */
>  int phy_device_register(struct phy_device *phydev)
>  {
> +	static atomic_t phyindex;
>  	int err;
>  
>  	err = mdiobus_register_device(&phydev->mdio);
> @@ -908,6 +910,7 @@ int phy_device_register(struct phy_device *phydev)
>  		goto out;
>  	}
>  
> +	phydev->phyindex = atomic_inc_return(&phyindex) - 1;
>  	err = device_add(&phydev->mdio.dev);
>  	if (err) {
>  		phydev_err(phydev, "failed to add\n");

-- 
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