On 9/13/2018 1:54 PM, Jason Gunthorpe wrote: > On Thu, Sep 13, 2018 at 01:03:42PM -0500, Steve Wise wrote: >> >> >> On 9/13/2018 12:19 PM, Jason Gunthorpe wrote: >>> On Thu, Sep 13, 2018 at 12:05:27PM -0500, Steve Wise wrote: >>>> >>>> >>>> On 7/25/2018 2:05 PM, Jason Gunthorpe wrote: >>>>> On Mon, Jul 16, 2018 at 02:07:57PM -0500, Steve Wise wrote: >>>>>> >>>>>> >>>>>> On 3/1/2018 11:18 AM, Jason Gunthorpe wrote: >>>>>>> On Thu, Mar 01, 2018 at 10:28:00AM -0600, Steve Wise wrote: >>>>>>>>> On Thu, Mar 01, 2018 at 09:29:04AM -0600, Steve Wise wrote: >>>>>>>>> >>>>>>>>>> Maybe to add a network interface to a soft-rdma device like rxe, we >>>>>>>> could >>>>>>>>> create a syntax like this: >>>>>>>>>> rdma link set rxe_eth0 dev eth0 >>>>>>>>> More like: >>>>>>>>> >>>>>>>>> rdma link add rxe_eth0 type rxe dev eth0 >>>>>>>>> >>>>>>>>> 'type rxe' triggers the kernel to dispatch to the rxe or siw driver to >>>>>>>>> create the interface. >>>>>>>> Type doesn't sound right though. in the current rdma synax, it would be >>>>>>>> 'dev'. Maybe: >>>>>>>> >>>>>>>> rdma link add rxe_eth0 dev rxe netdev eth0 >>>>>>> Type is the consistent tag with 'ip link add'. >>>>>> >>>>>> Hey guys, >>>>>> >>>>>> I'm starting to think about how to implement 'rdma link add/delete' for >>>>>> rxe. Does it make sense to add new members to the rdma_nldev_command >>>>>> enum in include/uapi/rdma/rdma_netlink.h for adding and deleting >>>>>> soft-rdma links to netdev interfaces? Something like >>>>>> RDMA_NLDEV_CMD_LINK_ADD and RDMA_NLDEV_CMD_LINK_DEL? Then add handlers >>>>>> to the nldev_cb_table array in drivers/infiniband/core/nldev.c. Can >>>>>> we assume there is only one soft-rdma driver for each rdma transport? >>>>>> That would enable a simple core->driver dispatch via an array of >>>>>> driver-specific handler functions that are indexed by the soft-rdma >>>>>> transport type. Or do we need something more general? >>>>>> >>>>>> Just thinking out loud here. What do you all think? >>>>> >>>>> You may as well follow the pattern ip link add uses.. >>>>> >>>>> See struct rtnl_link_ops ipoib_link_ops >>>>> >>>>> This way we can keep rxe as a module without creating a link time >>>>> dependency on the core module. >>>>> >>>>> Core code should match the 'type' tag with the '.kind' string member >>>>> just as ip does, and should pas a netlink attrs bundle in to the callback >>>>> like ip, see ipoib_new_child_link() >>>>> >>>>> The result should return the rdma id and name of the newly created >>>>> interface. >>>>> >>>> >>>> Should the rxe driver just register with an actual rtnl_link_ops? And >>>> use that rtnl core facility to dispatch callbacks? >>>> >>>> Or should we create a similar rdma_link_ops struct that includes the >>>> '.kind' and other appropriate fields, and have our own dispatcher in >>>> drivers/infiniband/core? Seems like we could simplify it some some... >>> >>> I think we have to do this to get the proper command line >>> interface.. Otherwise in userspace you have to parse the kind and >>> send a unique per driver message.. >>> >> >> I'm not advocating using RTM_NEWLINK, but just so we're on the same >> page: that infrastructure does already have a IFLA_INFO_KIND attribute. >> So our'rdma link add' could build and send an RTM_NEWLINK message and >> the net/rtnetlink.c core code would dispatch to whoever registered with >> .kind == 'rxe'. (and in the future .kind = 'siw' :) ). > > RTM_NEWLINK is only for creating netdevices.. > >> So I don't understand your comment about user space having to send a >> unique per-driver message? It would be a common RTM_NEWLINK message, but >> INFO_KIND attribute would identify the rdma driver. Am I missing >> something (probably)? > > We need a RDMA_NEWLINK with a RDMALA_INFO_KIND string that dispatches > to the right driver > >> Regardless, I would rather create an rdma-specific message and >> supporting structs/attributes to keep it simple. I mean these links are >> not 'ip link' netdev links. They are rdma links... > > Yes, rdma specific, but RDMA driver generic. > > Jason > Got it. Thanks Jason!
