netdev - Re: [PATCH net-next] phylink: add ASSERT_RTNL() on phylink connect functions

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Message-ID: <20191023131032.GZ25745@shell.armlinux.org.uk>
Date:   Wed, 23 Oct 2019 14:10:32 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Ioana Ciornei <ioana.ciornei@....com>
Cc:     davem@...emloft.net, netdev@...r.kernel.org, andrew@...n.ch
Subject: Re: [PATCH net-next] phylink: add ASSERT_RTNL() on phylink connect
 functions

On Wed, Oct 23, 2019 at 03:32:20PM +0300, Ioana Ciornei wrote:
> The appropriate assert on the rtnl lock is not present in phylink's
> connect functions which makes unusual calls to them not to be catched.
> Add the appropriate ASSERT_RTNL().

As I previously replied, this is not necessary.  It is safe to attach
PHYs _prior_ to the netdev being registered without taking the rtnl
lock, just like phylib's phy_connect()/phy_attach() are safe.

> 
> Signed-off-by: Ioana Ciornei <ioana.ciornei@....com>
> ---
>  drivers/net/phy/phylink.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index be7a2c0fa59b..d0aa0c861b2d 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -786,6 +786,8 @@ static int __phylink_connect_phy(struct phylink *pl, struct phy_device *phy,
>   */
>  int phylink_connect_phy(struct phylink *pl, struct phy_device *phy)
>  {
> +	ASSERT_RTNL();
> +
>  	/* Use PHY device/driver interface */
>  	if (pl->link_interface == PHY_INTERFACE_MODE_NA) {
>  		pl->link_interface = phy->interface;
> @@ -815,6 +817,8 @@ int phylink_of_phy_connect(struct phylink *pl, struct device_node *dn,
>  	struct phy_device *phy_dev;
>  	int ret;
>  
> +	ASSERT_RTNL();
> +
>  	/* Fixed links and 802.3z are handled without needing a PHY */
>  	if (pl->link_an_mode == MLO_AN_FIXED ||
>  	    (pl->link_an_mode == MLO_AN_INBAND &&
> -- 
> 1.9.1
> 
> 

-- 
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