On 25.02.2016 21:12, David Miller wrote:
From: Jiri Pirko <j...@resnulli.us> Date: Tue, 23 Feb 2016 16:51:25 +0100There a is need for some userspace API that would allow to expose things that are not directly related to any device class like net_device of ib_device, but rather chip-wide/switch-ASIC-wide stuff. Use cases: 1) get/set of port type (Ethernet/InfiniBand) 2) setting up port splitters - split port into multiple ones and squash again, enables usage of splitter cable 3) setting up shared buffers - shared among multiple ports within one chip (work in progress) 4) configuration of switch wide properties - resources division etc - This will allow to pass configuration that is unacceptable to be passed as a module option. First patch of this set introduces a new generic Netlink based interface, called "devlink". It is similar to nl80211 model and it is heavily influenced by it, including the API definition. The devlink introduction patch implements use cases 1) and 2). Other 2 are in development atm and will be addressed by follow-ups. It is very convenient for drivers to use devlink, as you can see in other patches in this set. Counterpart for devlink is userspace tool for now called "dl". Command line interface and outputs are derived from "ip" tool so it should be easy for users to get used to it.I am very close to applying this series as-is. The clincher for me is that there is precendence in the nl80211 stuff, so obviously whatever userland infrastructure sits on top of that has found a way to deal whatever perceived shortcomings devlink has.
Actually nl80211 phy interfaces aren't really managed by wpa_supplicant nor NetworkManager, but they use net_device names to discover those later on. In devlink we don't necessarily have netdev names, thus my only objection to this series is to switch to stable topology identifiers.
If all that people can come up with is "device names! omg UDEV!" and "multiple tools are hard to use!" That's awesome, because it means nobody has any real substantial objection to this facility. :-)
I do think this is important if a lot of devlinks are visible and they don't yet provide a net_device. One has to use e.g. pci identifiers or depend on module loading order. Especially I have no idea how this should work with devices where the module is not yet loaded (and most device drivers don't split between pci layer and net_device). This is even more complicated then the udev stuff we have nowadays.
Bye, Hannes
