On 9/13/2018 2:01 PM, Steve Wise wrote: > > > 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! > Since the rdma core currently assigned device name strings, I'm thinking to just follow that scheme. This leads to slightly different command syntax: rdma link add TYPE dev DEV EG: rdma link add rxe dev eth0 Then the kernel would return the resulting ib_device name and index. Steve.
