On 9/14/2018 1:34 PM, Jason Gunthorpe wrote: > On Fri, Sep 14, 2018 at 01:11:23PM -0500, Steve Wise wrote: >> >> >> 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. > > I would rather we specify the ib_device name from userspace from the > start.. > Why? This is not current practice for rdma devices: the core names them.
