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
