On 05.04.2021 11:29:31, Vincent MAILHOL wrote: > Hi Marc, > > On Wed. 17 Mar 2021 at 00:29, Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote: > > On 17.03.2021 00:16:01, Vincent MAILHOL wrote: > > > > I just had a look at the ethtool-netlink interface: > > > > > > > > | Documentation/networking/ethtool-netlink.rst > > > > > > > > this is much better designed than the CAN netlink interface. It was done > > > > by the pros and much later than CAN. :D So I'd like to have a similar > > > > structure for new CAN netlink stuff. > > > > > > > > So I think I'll remove this patch for now from can-next-testing. The > > > > kernel internal interface to tdc is still OK, we can leave it as is and > > > > change it if needed. But netlink is user space and I'd like to have it > > > > properly designed. > > > > > > Understood. However, I will need more time to read and understand > > > the ethtool-netlink interface. The new patch will come later, I > > > do not know when. > > > > No Problem > > I started to look at Ethtool netlink, but as far as my understanding > goes, this seems purely restricted to the ethtool application (i.e. > not to iproute2). I double checked the latest versions of iproute2 > but there isn’t a single #include <linux/ethtool_netlink.h> nor > anything else related to that new API. > > Please let me know if I missed the point. For example have a look at the RINGS_GET of ethtool-netlink.rst: | RINGS_GET | ========= | | Gets ring sizes like ``ETHTOOL_GRINGPARAM`` ioctl request. | | Request contents: | | ==================================== ====== ========================== | ``ETHTOOL_A_RINGS_HEADER`` nested request header | ==================================== ====== ========================== | | Kernel response contents: | | ==================================== ====== ========================== | ``ETHTOOL_A_RINGS_HEADER`` nested reply header | ``ETHTOOL_A_RINGS_RX_MAX`` u32 max size of RX ring | ``ETHTOOL_A_RINGS_RX_MINI_MAX`` u32 max size of RX mini ring | ``ETHTOOL_A_RINGS_RX_JUMBO_MAX`` u32 max size of RX jumbo ring | ``ETHTOOL_A_RINGS_TX_MAX`` u32 max size of TX ring | ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring | ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring | ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring | ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring | ==================================== ====== ========================== The response consists of a header and several nested values. This looks to me to be the netlink way to serialize a C-struct. If I understand your code correctly it was just the values without the nested header. | RINGS_SET | ========= | | Sets ring sizes like ``ETHTOOL_SRINGPARAM`` ioctl request. | | Request contents: | | ==================================== ====== ========================== | ``ETHTOOL_A_RINGS_HEADER`` nested reply header | ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring | ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring | ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring | ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring | ==================================== ====== ========================== | | Kernel checks that requested ring sizes do not exceed limits reported by | driver. Driver may impose additional constraints and may not suspport all | attributes. regards, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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