RDMA/mlx5: Create ODP EQ only when ODP MR is created

There is no need to create the ODP EQ if the user doesn't use ODP MRs.
Hence, create it only when the first ODP MR is created. This EQ will be
destroyed only when the device is unloaded.
This will decrease the number of EQs created per device. for example: If
we creates 1K devices (SF/VF/etc'), than we will decrease the num of EQs
by 1K.

Link: https://lore.kernel.org/r/20210314125418.179716-1-leon@kernel.orgSigned-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -1080,6 +1080,7 @@ struct mlx5_ib_dev {
 	struct mutex			slow_path_mutex;
 	struct ib_odp_caps	odp_caps;
 	u64			odp_max_size;
+	struct mutex		odp_eq_mutex;
 	struct mlx5_ib_pf_eq	odp_pf_eq;
 
 	struct xarray		odp_mkeys;
@@ -1358,6 +1359,7 @@ struct ib_mr *mlx5_ib_reg_dm_mr(struct ib_pd *pd, struct ib_dm *dm,
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
 void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev);
 int mlx5_ib_odp_init_one(struct mlx5_ib_dev *ibdev);
+int mlx5r_odp_create_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq);
 void mlx5_ib_odp_cleanup_one(struct mlx5_ib_dev *ibdev);
 int __init mlx5_ib_odp_init(void);
 void mlx5_ib_odp_cleanup(void);
@@ -1377,6 +1379,11 @@ static inline void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev)
 }
 
 static inline int mlx5_ib_odp_init_one(struct mlx5_ib_dev *ibdev) { return 0; }
+static inline int mlx5r_odp_create_eq(struct mlx5_ib_dev *dev,
+				      struct mlx5_ib_pf_eq *eq)
+{
+	return 0;
+}
 static inline void mlx5_ib_odp_cleanup_one(struct mlx5_ib_dev *ibdev) {}
 static inline int mlx5_ib_odp_init(void) { return 0; }
 static inline void mlx5_ib_odp_cleanup(void)				    {}

drivers/infiniband/hw/mlx5/mr.c

@@ -1500,6 +1500,9 @@ static struct ib_mr *create_user_odp_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (!IS_ENABLED(CONFIG_INFINIBAND_ON_DEMAND_PAGING))
 		return ERR_PTR(-EOPNOTSUPP);
 
+	err = mlx5r_odp_create_eq(dev, &dev->odp_pf_eq);
+	if (err)
+		return ERR_PTR(err);
 	if (!start && length == U64_MAX) {
 		if (iova != 0)
 			return ERR_PTR(-EINVAL);

drivers/infiniband/hw/mlx5/odp.c

@@ -1531,20 +1531,24 @@ enum {
 	MLX5_IB_NUM_PF_DRAIN	= 64,
 };
 
-static int
-mlx5_ib_create_pf_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
+int mlx5r_odp_create_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
 {
 	struct mlx5_eq_param param = {};
-	int err;
+	int err = 0;
 
+	mutex_lock(&dev->odp_eq_mutex);
+	if (eq->core)
+		goto unlock;
 	INIT_WORK(&eq->work, mlx5_ib_eq_pf_action);
 	spin_lock_init(&eq->lock);
 	eq->dev = dev;
 
 	eq->pool = mempool_create_kmalloc_pool(MLX5_IB_NUM_PF_DRAIN,
 					       sizeof(struct mlx5_pagefault));
-	if (!eq->pool)
-		return -ENOMEM;
+	if (!eq->pool) {
+		err = -ENOMEM;
+		goto unlock;
+	}
 
 	eq->wq = alloc_workqueue("mlx5_ib_page_fault",
 				 WQ_HIGHPRI | WQ_UNBOUND | WQ_MEM_RECLAIM,
@@ -1555,7 +1559,7 @@ mlx5_ib_create_pf_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
 	}
 
 	eq->irq_nb.notifier_call = mlx5_ib_eq_pf_int;
-	param = (struct mlx5_eq_param) {
+	param = (struct mlx5_eq_param){
 		.irq_index = 0,
 		.nent = MLX5_IB_NUM_PF_EQE,
 	};
@@ -1571,21 +1575,27 @@ mlx5_ib_create_pf_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
 		goto err_eq;
 	}
 
+	mutex_unlock(&dev->odp_eq_mutex);
 	return 0;
 err_eq:
 	mlx5_eq_destroy_generic(dev->mdev, eq->core);
 err_wq:
+	eq->core = NULL;
 	destroy_workqueue(eq->wq);
 err_mempool:
 	mempool_destroy(eq->pool);
+unlock:
+	mutex_unlock(&dev->odp_eq_mutex);
 	return err;
 }
 
 static int
-mlx5_ib_destroy_pf_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
+mlx5_ib_odp_destroy_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
 {
 	int err;
 
+	if (!eq->core)
+		return 0;
 	mlx5_eq_disable(dev->mdev, eq->core, &eq->irq_nb);
 	err = mlx5_eq_destroy_generic(dev->mdev, eq->core);
 	cancel_work_sync(&eq->work);
@@ -1642,8 +1652,7 @@ int mlx5_ib_odp_init_one(struct mlx5_ib_dev *dev)
 		}
 	}
 
-	ret = mlx5_ib_create_pf_eq(dev, &dev->odp_pf_eq);
-
+	mutex_init(&dev->odp_eq_mutex);
 	return ret;
 }
 
@@ -1652,7 +1661,7 @@ void mlx5_ib_odp_cleanup_one(struct mlx5_ib_dev *dev)
 	if (!(dev->odp_caps.general_caps & IB_ODP_SUPPORT))
 		return;
 
-	mlx5_ib_destroy_pf_eq(dev, &dev->odp_pf_eq);
+	mlx5_ib_odp_destroy_eq(dev, &dev->odp_pf_eq);
 }
 
 int mlx5_ib_odp_init(void)