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RDMA/mlx5: Remove the redundant MLX5_IB_STAGE_UAR stage

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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>
Link: https://patch.msgid.link/feaa84ec6f20468b4935c439923e9266122a93d0.1747134130.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>
This commit is contained in:
Yishai Hadas
2025-05-13 14:02:40 +03:00
committed by Leon Romanovsky
parent 21508c8c97
commit 972db388d4
2 changed files with 0 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/infiniband/hw/mlx5/main.c
View File

@@ -4422,17 +4422,6 @@ static void mlx5_ib_stage_cong_debugfs_cleanup(struct mlx5_ib_dev *dev)
mlx5_core_native_port_num(dev->mdev) - 1);
}
static int mlx5_ib_stage_uar_init(struct mlx5_ib_dev *dev)
{
dev->mdev->priv.uar = mlx5_get_uars_page(dev->mdev);
return PTR_ERR_OR_ZERO(dev->mdev->priv.uar);
}
static void mlx5_ib_stage_uar_cleanup(struct mlx5_ib_dev *dev)
{
mlx5_put_uars_page(dev->mdev, dev->mdev->priv.uar);
}
static int mlx5_ib_stage_bfrag_init(struct mlx5_ib_dev *dev)
{
int err;
@@ -4662,9 +4651,6 @@ static const struct mlx5_ib_profile pf_profile = {
STAGE_CREATE(MLX5_IB_STAGE_CONG_DEBUGFS,
mlx5_ib_stage_cong_debugfs_init,
mlx5_ib_stage_cong_debugfs_cleanup),
STAGE_CREATE(MLX5_IB_STAGE_UAR,
mlx5_ib_stage_uar_init,
mlx5_ib_stage_uar_cleanup),
STAGE_CREATE(MLX5_IB_STAGE_BFREG,
mlx5_ib_stage_bfrag_init,
mlx5_ib_stage_bfrag_cleanup),
@@ -4722,9 +4708,6 @@ const struct mlx5_ib_profile raw_eth_profile = {
STAGE_CREATE(MLX5_IB_STAGE_CONG_DEBUGFS,
mlx5_ib_stage_cong_debugfs_init,
mlx5_ib_stage_cong_debugfs_cleanup),
STAGE_CREATE(MLX5_IB_STAGE_UAR,
mlx5_ib_stage_uar_init,
mlx5_ib_stage_uar_cleanup),
STAGE_CREATE(MLX5_IB_STAGE_BFREG,
mlx5_ib_stage_bfrag_init,
mlx5_ib_stage_bfrag_cleanup),

1
drivers/infiniband/hw/mlx5/mlx5_ib.h
View File

@@ -1006,7 +1006,6 @@ enum mlx5_ib_stages {
MLX5_IB_STAGE_ODP,
MLX5_IB_STAGE_COUNTERS,
MLX5_IB_STAGE_CONG_DEBUGFS,
MLX5_IB_STAGE_UAR,
MLX5_IB_STAGE_BFREG,
MLX5_IB_STAGE_PRE_IB_REG_UMR,
MLX5_IB_STAGE_WHITELIST_UID,