Re: [PATCH RFC net-next v8 06/13] net: Add struct kernel_ethtool_ts_info

From: "Köry Maincent" <kory.maincent@bootlin.com>
To: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Richard Cochran <richardcochran@gmail.com>,
	Radu Pirea <radu-nicolae.pirea@oss.nxp.com>,
	Jay Vosburgh <j.vosburgh@gmail.com>,
	Andy Gospodarek <andy@greyhouse.net>,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Claudiu Beznea <claudiu.beznea@tuxon.dev>,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Horatiu Vultur <horatiu.vultur@microchip.com>,
	UNGLinuxDriver@microchip.com, Simon Horman <horms@kernel.org>,
	Vladimir Oltean <vladimir.oltean@nxp.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org,
	Maxime Chevallier <maxime.chevallier@bootlin.com>
Subject: Re: [PATCH RFC net-next v8 06/13] net: Add struct kernel_ethtool_ts_info
Date: Mon, 19 Feb 2024 11:57:36 +0100	[thread overview]
Message-ID: <20240219115736.7138a2a0@kmaincent-XPS-13-7390> (raw)
In-Reply-To: <87frxsgt4i.fsf@nvidia.com>

On Fri, 16 Feb 2024 10:27:32 -0800
Rahul Rameshbabu <rrameshbabu@nvidia.com> wrote:

> > +/**
> > + * struct kernel_ethtool_ts_info - kernel copy of struct ethtool_ts_info
> > + * @cmd: command number = %ETHTOOL_GET_TS_INFO
> > + * @so_timestamping: bit mask of the sum of the supported SO_TIMESTAMPING
> > flags
> > + * @phc_index: device index of the associated PHC, or -1 if there is none
> > + * @tx_types: bit mask of the supported hwtstamp_tx_types enumeration
> > values
> > + * @rx_filters: bit mask of the supported hwtstamp_rx_filters enumeration
> > values
> > + */
> > +struct kernel_ethtool_ts_info {
> > +	u32 cmd;
> > +	u32 so_timestamping;
> > +	int phc_index;
> > +	enum hwtstamp_tx_types tx_types;  
> 
> I might just be terrible at reading code, but isn't this what
> tx_reserved in ethtool_ts_info is for? I feel like using one of the
> reserved memspaces for this enum removes the need to make
> kernel_ethtool_ts_info? I might be missing something obvious however.

I did it to prepare the introduction phc_qualifier in patch 12. I am not sure it
would be wise to put it under tx/rx_reserved field. IMHO create a new kernel
structure is cleaner for that than the hack of using one of the tx/rx_reserved
field.

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com