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Date:   Mon, 25 Jul 2022 01:33:48 +0300
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Christian Marangi <ansuelsmth@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>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [net-next PATCH v3 02/14] net: dsa: qca8k: make mib autocast
 feature optional
Message-ID: <20220724223348.tqh45ygbuyw7jp5s@skbuf>
References: <20220723141845.10570-1-ansuelsmth@gmail.com>
 <20220723141845.10570-1-ansuelsmth@gmail.com>
 <20220723141845.10570-3-ansuelsmth@gmail.com>
 <20220723141845.10570-3-ansuelsmth@gmail.com>
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On Sat, Jul 23, 2022 at 04:18:33PM +0200, Christian Marangi wrote:
> Some switch may not support mib autocast feature and require the legacy
> way of reading the regs directly.
> Make the mib autocast feature optional and permit to declare support for
> it using match_data struct in a dedicated qca8k_info_ops struct.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/net/dsa/qca/qca8k.c | 11 +++++++++--
>  drivers/net/dsa/qca/qca8k.h |  5 +++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/dsa/qca/qca8k.c b/drivers/net/dsa/qca/qca8k.c
> index 212b284f9f73..9820c5942d2a 100644
> --- a/drivers/net/dsa/qca/qca8k.c
> +++ b/drivers/net/dsa/qca/qca8k.c
> @@ -2104,8 +2104,8 @@ qca8k_get_ethtool_stats(struct dsa_switch *ds, int port,
>  	u32 hi = 0;
>  	int ret;
>  
> -	if (priv->mgmt_master &&
> -	    qca8k_get_ethtool_stats_eth(ds, port, data) > 0)
> +	if (priv->mgmt_master && priv->info->ops.autocast_mib &&
> +	    priv->info->ops.autocast_mib(ds, port, data) > 0)
>  		return;
>  
>  	for (i = 0; i < priv->info->mib_count; i++) {
> @@ -3248,20 +3248,27 @@ static int qca8k_resume(struct device *dev)
>  static SIMPLE_DEV_PM_OPS(qca8k_pm_ops,
>  			 qca8k_suspend, qca8k_resume);
>  
> +static const struct qca8k_info_ops qca8xxx_ops = {
> +	.autocast_mib = qca8k_get_ethtool_stats_eth,
> +};
> +
>  static const struct qca8k_match_data qca8327 = {
>  	.id = QCA8K_ID_QCA8327,
>  	.reduced_package = true,
>  	.mib_count = QCA8K_QCA832X_MIB_COUNT,
> +	.ops = qca8xxx_ops,
>  };
>  
>  static const struct qca8k_match_data qca8328 = {
>  	.id = QCA8K_ID_QCA8327,
>  	.mib_count = QCA8K_QCA832X_MIB_COUNT,
> +	.ops = qca8xxx_ops,
>  };
>  
>  static const struct qca8k_match_data qca833x = {
>  	.id = QCA8K_ID_QCA8337,
>  	.mib_count = QCA8K_QCA833X_MIB_COUNT,
> +	.ops = qca8xxx_ops,
>  };
>  
>  static const struct of_device_id qca8k_of_match[] = {
> diff --git a/drivers/net/dsa/qca/qca8k.h b/drivers/net/dsa/qca/qca8k.h
> index 0b990b46890a..7b4a698f092a 100644
> --- a/drivers/net/dsa/qca/qca8k.h
> +++ b/drivers/net/dsa/qca/qca8k.h
> @@ -324,10 +324,15 @@ enum qca8k_mid_cmd {
>  	QCA8K_MIB_CAST = 3,
>  };
>  
> +struct qca8k_info_ops {
> +	int (*autocast_mib)(struct dsa_switch *ds, int port, u64 *data);
> +};
> +
>  struct qca8k_match_data {
>  	u8 id;
>  	bool reduced_package;
>  	u8 mib_count;
> +	struct qca8k_info_ops ops;

This creates a copy of the structure for each of qca8327, qca8328, etc etc,
which in turn will consume 3 times more space than necessary when new
ops are added. Could you make this "const struct qca8k_ops *ops"?

>  };
>  
>  enum {
> -- 
> 2.36.1
>