Re: [PATCH rdma-next] RDMA/mlx5: Don't compare mkey tags in DEVX indirect mkey

[Leon Romanovsky <leon@kernel.org>]

On Sun, Jul 31, 2022 at 11:26:36AM +0300, Leon Romanovsky wrote:
> From: Aharon Landau <aharonl@nvidia.com>
> 
> According to the ib spec:
> If the CI supports the Base Memory Management Extensions defined in this
> specification, the L_Key format must consist of:
> 24 bit index in the most significant bits of the R_Key, and
> 8 bit key in the least significant bits of the R_Key
> Through a successful Allocate L_Key verb invocation, the CI must let the
> consumer own the key portion of the returned R_Key
> 
> Therefore, when creating a mkey using DEVX, the consumer is allowed to
> change the key part. The kernel should compare only the index part of a
> R_Key to determine equality with another R_Key.
> 
> Adding capability in order not to break backward compatibility.
> 
> Fixes: 534fd7aac56a ("IB/mlx5: Manage indirection mkey upon DEVX flow for ODP")
> Signed-off-by: Aharon Landau <aharonl@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/hw/mlx5/main.c | 3 +++
>  drivers/infiniband/hw/mlx5/odp.c  | 3 ++-
>  include/uapi/rdma/mlx5-abi.h      | 1 +
>  3 files changed, 6 insertions(+), 1 deletion(-)
> 

Thanks, applied