Re: [PATCH rdma-next 2/5] RDMA/core: Don't depend device ODP capabilities on kconfig option

[Jason Gunthorpe <jgg@mellanox.com>]

On Thu, Dec 20, 2018 at 11:23:15AM +0200, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@mellanox.com>
> 
> Device capability bits are exposing what specific device supports from
> HW perspective. Those bits are not dependent on kernel configurations
> and RDMA/core should ensure that proper interfaces to users will be
> disabled if CONFIG_INFINIBAND_ON_DEMAND_PAGING is not set.
> 
> Fixes: f4056bfd8ccf ("IB/core: Add on demand paging caps to ib_uverbs_ex_query_device")
> Fixes: 8cdd312cfed7 ("IB/mlx5: Implement the ODP capability query verb")
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
>  drivers/infiniband/core/uverbs_cmd.c | 2 --
>  drivers/infiniband/hw/mlx5/main.c    | 2 --
>  2 files changed, 4 deletions(-)
> 
> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
> index 6b12cc5f97b2..549d9eedf62e 100644
> +++ b/drivers/infiniband/core/uverbs_cmd.c
> @@ -3609,7 +3609,6 @@ static int ib_uverbs_ex_query_device(struct uverbs_attr_bundle *attrs)
>  
>  	copy_query_dev_fields(ucontext, &resp.base, &attr);
>  
> -#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
>  	resp.odp_caps.general_caps = attr.odp_caps.general_caps;
>  	resp.odp_caps.per_transport_caps.rc_odp_caps =
>  		attr.odp_caps.per_transport_caps.rc_odp_caps;
> @@ -3617,7 +3616,6 @@ static int ib_uverbs_ex_query_device(struct uverbs_attr_bundle *attrs)
>  		attr.odp_caps.per_transport_caps.uc_odp_caps;
>  	resp.odp_caps.per_transport_caps.ud_odp_caps =
>  		attr.odp_caps.per_transport_caps.ud_odp_caps;
> -#endif

This one is maybe OK, assuming the driver fills in 0..

>  	resp.timestamp_mask = attr.timestamp_mask;
>  	resp.hca_core_clock = attr.hca_core_clock;
> diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> index 6584e638387a..d7e5ba5034aa 100644
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -923,11 +923,9 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
>  	props->hca_core_clock = MLX5_CAP_GEN(mdev, device_frequency_khz);
>  	props->timestamp_mask = 0x7FFFFFFFFFFFFFFFULL;
>  
> -#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
>  	if (MLX5_CAP_GEN(mdev, pg))
>  		props->device_cap_flags |= IB_DEVICE_ON_DEMAND_PAGING;
>  	props->odp_caps = dev->odp_caps;
> -#endif

But shouldn't this be protected? If the driver has compiled out ODP it
shouldn't set the cap flag...

Jason