Re: [PATCH] RDMA/rxe: prevent rxe creation on top of vlan interface

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Aug 11, 2020 at 06:04:15PM +0300, Mohammad Heib wrote:
> Creating rxe device on top of vlan interface will create a non-functional device
> that has an empty gids table and can't be used for rdma cm communication.
> 
> This is caused by the logic in enum_all_gids_of_dev_cb()/is_eth_port_of_netdev(),
> which only considers networks connected to "upper devices" of the configured
> network device, resulting in an empty set of gids for a vlan interface,
> and attempts to connect via this rdma device fail in cm_init_av_for_response
> because no gids can be resolved.
> 
> apparently, this behavior was implemented to fit the HW-RoCE devices that create
> RoCE device per port, therefore RXE must behave the same like HW-RoCE devices
> and create rxe device per real device only.
> 
> In order to communicate via a vlan interface, the user must use the gid index of
> the vlan address instead of creating rxe over vlan.
> 
> Signed-off-by: Mohammad Heib <goody698@gmail.com>
> ---
>  drivers/infiniband/sw/rxe/rxe.c       | 6 ++++++
>  drivers/infiniband/sw/rxe/rxe_sysfs.c | 6 ++++++
>  2 files changed, 12 insertions(+)

It would be better to somehow fix things so the gid table was properly
populated, but until that is done, blocking it is a reasonable thing
to do.

Applied to for-next, thanks

Jason