[PATCH v8 1/2] IB/mlx5: Fix success return path and mutex initialization

[Prathamesh Deshpande <prathameshdeshpande7@gmail.com>]

Fix an incorrect return path in mlx5_ib_alloc_transport_domain() where
a success case could return an uninitialized error value instead of 0.

Additionally, move dev->lb.mutex initialization to
mlx5_ib_stage_init_init(). This ensures the mutex is initialized
before potential access by create_raw_packet_qp_tir(), preventing
a null pointer dereference.

Signed-off-by: Prathamesh Deshpande <prathameshdeshpande7@gmail.com>
---
v8:
- Resubmitted as a fresh, independent thread per maintainer request.
- No functional changes since v7.
v7:
- Split from the main loopback refactor into a standalone patch to
  improve bisection and isolate the return-value fix.
v1-v6:
- Part of the combined "IB/mlx5: Fix loopback enablement state and 
  resource leaks" patch.

 drivers/infiniband/hw/mlx5/main.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index b74bf2697655..f49f746bc5bd 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -2068,7 +2068,7 @@ static int mlx5_ib_alloc_transport_domain(struct mlx5_ib_dev *dev, u32 *tdn,
 	if ((MLX5_CAP_GEN(dev->mdev, port_type) != MLX5_CAP_PORT_TYPE_ETH) ||
 	    (!MLX5_CAP_GEN(dev->mdev, disable_local_lb_uc) &&
 	     !MLX5_CAP_GEN(dev->mdev, disable_local_lb_mc)))
-		return err;
+		return 0;
 
 	return mlx5_ib_enable_lb(dev, true, false);
 }
@@ -4515,6 +4515,7 @@ static int mlx5_ib_stage_init_init(struct mlx5_ib_dev *dev)
 	mutex_init(&dev->data_direct_lock);
 	INIT_LIST_HEAD(&dev->qp_list);
 	spin_lock_init(&dev->reset_flow_resource_lock);
+	mutex_init(&dev->lb.mutex);
 	xa_init(&dev->odp_mkeys);
 	xa_init(&dev->sig_mrs);
 	atomic_set(&dev->mkey_var, 0);
@@ -4786,11 +4787,6 @@ static int mlx5_ib_stage_caps_init(struct mlx5_ib_dev *dev)
 	if (err)
 		return err;
 
-	if ((MLX5_CAP_GEN(dev->mdev, port_type) == MLX5_CAP_PORT_TYPE_ETH) &&
-	    (MLX5_CAP_GEN(dev->mdev, disable_local_lb_uc) ||
-	     MLX5_CAP_GEN(dev->mdev, disable_local_lb_mc)))
-		mutex_init(&dev->lb.mutex);
-
 	if (MLX5_CAP_GEN_64(dev->mdev, general_obj_types) &
 			MLX5_GENERAL_OBJ_TYPES_CAP_VIRTIO_NET_Q) {
 		err = mlx5_ib_init_var_region(dev);
-- 
2.43.0