On Mon, Dec 12, 2022 at 08:51:19AM -0400, Jason Gunthorpe wrote:
> On Mon, Dec 12, 2022 at 11:22:40AM +0200, Kamal Heib wrote:
> > Make sure that the requested net_device is not already associated with
> > an ib_device before trying to create a new ib_device that will be
> > associated with the same net_device, this is needed to avoid creating
> > siw and rxe devices that will be associated with the same net_device.
> >
> > Fixes: 3856ec4b93c9 ("RDMA/core: Add RDMA_NLDEV_CMD_NEWLINK/DELLINK support")
> > Signed-off-by: Kamal Heib <kheib@xxxxxxxxxx>
> > ---
> > drivers/infiniband/core/nldev.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> > index a981ac2f0975..376c9e158556 100644
> > --- a/drivers/infiniband/core/nldev.c
> > +++ b/drivers/infiniband/core/nldev.c
> > @@ -1696,6 +1696,7 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
> > const struct rdma_link_ops *ops;
> > char ndev_name[IFNAMSIZ];
> > struct net_device *ndev;
> > + struct ib_device *ibdev;
> > char type[IFNAMSIZ];
> > int err;
> >
> > @@ -1718,6 +1719,12 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
> > if (!ndev)
> > return -ENODEV;
> >
> > + ibdev = ib_device_get_by_netdev(ndev, RDMA_DRIVER_UNKNOWN);
> > + if (ibdev) {
> > + ib_device_put(ibdev);
> > + return -EINVAL;
> > + }
>
> This is racy
It can be seen as best effort.
>
> What is wrong with creating two IB devices on top of the same net device?
Any place where we need to convert from ndev to ib will return random answer.
>
> Jason
