RDMA/mlx5: Remove the redundant MLX5_IB_STAGE_UAR stage
The MLX5_IB_STAGE_UAR stage in the RDMA driver is redundant and should
be removed.
Responsibility for initializing the device's UAR pointer
(mdev->priv.uar) lies with mlx5_core, which already sets it during the
mlx5_load() process.
At present, the RDMA UAR stage overwrites this pointer, which was
correctly initialized by mlx5_core, creating the risk of inconsistency.
Ownership and management of the UAR pointer should remain exclusively
within mlx5_core.
In the current upstream code, we luckily receive the same pointer, since
mlx5_get_uars_page() still finds available BF registers for that UAR,
allowing it to be shared.
However, future changes in mlx5_core may expose this flaw.
For instance, if mlx5_alloc_bfreg() is invoked twice before the RDMA UAR
stage runs, the RDMA driver may overwrite the UAR allocated by
mlx5_core.
This could lead to real bugs. For example, if mlx5_ib is unloaded
(rmmod), it might free the UAR, leaving mlx5_core with a dangling
reference to an invalid UAR.
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Reviewed-by: Fan Li <fanl@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
2 files changed
