[PATCH v4 04/10] common/mlx5: add null MR functions

[Thomas Monjalon]

From: Gregory Etelson <getelson at nvidia.com>

Add functions to allocate and free a null Memory Region (MR)
using ibverbs on Linux.

There is no implementation for DevX on Windows.

Signed-off-by: Gregory Etelson <getelson at nvidia.com>
Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
---
 drivers/common/mlx5/linux/mlx5_common_verbs.c | 35 +++++++++++++++++++
 drivers/common/mlx5/mlx5_common_mr.h          |  9 +++++
 drivers/common/mlx5/windows/mlx5_common_os.c  | 16 +++++++++
 3 files changed, 60 insertions(+)

diff --git a/drivers/common/mlx5/linux/mlx5_common_verbs.c b/drivers/common/mlx5/linux/mlx5_common_verbs.c
index 2322d9d033..6d44e1f566 100644
--- a/drivers/common/mlx5/linux/mlx5_common_verbs.c
+++ b/drivers/common/mlx5/linux/mlx5_common_verbs.c
@@ -161,3 +161,38 @@ mlx5_os_set_reg_mr_cb(mlx5_reg_mr_t *reg_mr_cb, mlx5_dereg_mr_t *dereg_mr_cb)
 	*reg_mr_cb = mlx5_common_verbs_reg_mr;
 	*dereg_mr_cb = mlx5_common_verbs_dereg_mr;
 }
+
+RTE_EXPORT_INTERNAL_SYMBOL(mlx5_os_alloc_null_mr)
+struct mlx5_pmd_mr *
+mlx5_os_alloc_null_mr(struct rte_device *dev, void *pd)
+{
+	struct ibv_mr *ibv_mr;
+	struct mlx5_pmd_mr *null_mr;
+
+	null_mr = mlx5_malloc(MLX5_MEM_ZERO, sizeof(*null_mr), 0, dev->numa_node);
+	if (!null_mr)
+		return NULL;
+	ibv_mr = mlx5_glue->alloc_null_mr(pd);
+	if (!ibv_mr) {
+		mlx5_free(null_mr);
+		return NULL;
+	}
+	*null_mr = (struct mlx5_pmd_mr) {
+		.lkey = rte_cpu_to_be_32(ibv_mr->lkey),
+		.addr = ibv_mr->addr,
+		.len = ibv_mr->length,
+		.obj = (void *)ibv_mr,
+	};
+	return null_mr;
+}
+
+RTE_EXPORT_INTERNAL_SYMBOL(mlx5_os_free_null_mr)
+void
+mlx5_os_free_null_mr(struct mlx5_pmd_mr *null_mr)
+{
+	if (!null_mr)
+		return;
+	if (null_mr->obj)
+		claim_zero(mlx5_glue->dereg_mr(null_mr->obj));
+	mlx5_free(null_mr);
+}
diff --git a/drivers/common/mlx5/mlx5_common_mr.h b/drivers/common/mlx5/mlx5_common_mr.h
index cf7c685e9b..00f3d832c3 100644
--- a/drivers/common/mlx5/mlx5_common_mr.h
+++ b/drivers/common/mlx5/mlx5_common_mr.h
@@ -21,6 +21,8 @@
 #include "mlx5_common_mp.h"
 #include "mlx5_common_defs.h"
 
+struct rte_device;
+
 /* mlx5 PMD MR struct. */
 struct mlx5_pmd_mr {
 	uint32_t	     lkey;
@@ -258,6 +260,13 @@ __rte_internal
 void
 mlx5_os_set_reg_mr_cb(mlx5_reg_mr_t *reg_mr_cb, mlx5_dereg_mr_t *dereg_mr_cb);
 
+__rte_internal
+struct mlx5_pmd_mr *
+mlx5_os_alloc_null_mr(struct rte_device *dev, void *pd);
+__rte_internal
+void
+mlx5_os_free_null_mr(struct mlx5_pmd_mr *null_mr);
+
 __rte_internal
 int
 mlx5_mr_mempool_register(struct mlx5_common_device *cdev,
diff --git a/drivers/common/mlx5/windows/mlx5_common_os.c b/drivers/common/mlx5/windows/mlx5_common_os.c
index 16fcc5f9fc..692517a9bf 100644
--- a/drivers/common/mlx5/windows/mlx5_common_os.c
+++ b/drivers/common/mlx5/windows/mlx5_common_os.c
@@ -454,6 +454,22 @@ mlx5_os_set_reg_mr_cb(mlx5_reg_mr_t *reg_mr_cb, mlx5_dereg_mr_t *dereg_mr_cb)
 	*dereg_mr_cb = mlx5_os_dereg_mr;
 }
 
+RTE_EXPORT_INTERNAL_SYMBOL(mlx5_os_alloc_null_mr)
+struct mlx5_pmd_mr *
+mlx5_os_alloc_null_mr(struct rte_device *dev, void *pd)
+{
+	RTE_SET_USED(dev);
+	RTE_SET_USED(pd);
+	return NULL;
+}
+
+RTE_EXPORT_INTERNAL_SYMBOL(mlx5_os_free_null_mr)
+void
+mlx5_os_free_null_mr(struct mlx5_pmd_mr *null_mr)
+{
+	RTE_SET_USED(null_mr);
+}
+
 /*
  * In Windows, no need to wrap the MR, no known issue for it in kernel.
  * Use the regular function to create direct MR.
-- 
2.54.0