Re: [PATCH 3/4] net: ti: am65-cpsw-nuss: Add switchdev support

From: Andrew Lunn <andrew@lunn.ch>
To: Vignesh Raghavendra <vigneshr@ti.com>
Cc: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Jonathan Corbet <corbet@lwn.net>, Jiri Pirko <jiri@nvidia.com>,
	netdev@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Linux ARM Mailing List <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/4] net: ti: am65-cpsw-nuss: Add switchdev support
Date: Mon, 30 Nov 2020 18:20:34 +0100	[thread overview]
Message-ID: <20201130172034.GF2073444@lunn.ch> (raw)
In-Reply-To: <20201130082046.16292-4-vigneshr@ti.com>

> +static int am65_cpsw_port_stp_state_set(struct am65_cpsw_port *port,
> +					struct switchdev_trans *trans, u8 state)
> +{
> +	struct am65_cpsw_common *cpsw = port->common;
> +	u8 cpsw_state;
> +	int ret = 0;
> +
> +	if (switchdev_trans_ph_prepare(trans))
> +		return 0;
> +
> +	switch (state) {
> +	case BR_STATE_FORWARDING:
> +		cpsw_state = ALE_PORT_STATE_FORWARD;
> +		break;
> +	case BR_STATE_LEARNING:
> +		cpsw_state = ALE_PORT_STATE_LEARN;
> +		break;
> +	case BR_STATE_DISABLED:
> +		cpsw_state = ALE_PORT_STATE_DISABLE;
> +		break;
> +	case BR_STATE_LISTENING:
> +	case BR_STATE_BLOCKING:
> +		cpsw_state = ALE_PORT_STATE_BLOCK;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}

Strictly speaking, the:

> +	if (switchdev_trans_ph_prepare(trans))
> +		return 0;

should be here. In the prepare phase, you are suppose to validate you
can do the requested action, and return an error is not. In second
phase, actually carrying out the action, you then never return an
error.

But in this case, you are handling all the bridge states, so it should
not matter.

    Andrew