[dpdk-dev] [PATCH v2] common/mlx5: free MR resource while device DMA unmap

[Jiawei Wang]

mlx5 PMD created the MR (Memory Region) resource on the
mlx5_dma_map call to make the memory available for DMA
operations. On the mlx5_dma_unmap call the MR resource
was not freed but inserted to MR Free list for further
garbage collection.
Actual MR resource destroying happened on device stop
call. That caused the runtime out of memory in case of
application performed multiple DMA map/unmap calls.

The fix immediately frees the MR resource on mlx5_dma_unmap
call not engaging the list. The export for mlx5_mr_free
function from common PMD part is added as well.

Fixes: 989e999d9305 ("net/mlx5: support PCI device DMA map and unmap")
Cc: stable at dpdk.org

Signed-off-by: Jiawei Wang <jiaweiw at nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/common/mlx5/mlx5_common_mr.c | 12 ++++++------
 drivers/common/mlx5/mlx5_common_mr.h |  4 ++++
 drivers/common/mlx5/version.map      |  1 +
 drivers/net/mlx5/mlx5_mr.c           |  2 +-
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/common/mlx5/mlx5_common_mr.c b/drivers/common/mlx5/mlx5_common_mr.c
index 23324c0..7c25541 100644
--- a/drivers/common/mlx5/mlx5_common_mr.c
+++ b/drivers/common/mlx5/mlx5_common_mr.c
@@ -436,8 +436,8 @@ struct mlx5_mr *
  * @param mr
  *   Pointer to MR to free.
  */
-static void
-mr_free(struct mlx5_mr *mr, mlx5_dereg_mr_t dereg_mr_cb)
+void
+mlx5_mr_free(struct mlx5_mr *mr, mlx5_dereg_mr_t dereg_mr_cb)
 {
 	if (mr == NULL)
 		return;
@@ -492,7 +492,7 @@ struct mlx5_mr *
 		struct mlx5_mr *mr = mr_next;
 
 		mr_next = LIST_NEXT(mr, mr);
-		mr_free(mr, share_cache->dereg_mr_cb);
+		mlx5_mr_free(mr, share_cache->dereg_mr_cb);
 	}
 }
 
@@ -702,7 +702,7 @@ struct mlx5_mr *
 		data.start = RTE_ALIGN_FLOOR(addr, msl->page_sz);
 		data.end = data.start + msl->page_sz;
 		rte_mcfg_mem_read_unlock();
-		mr_free(mr, share_cache->dereg_mr_cb);
+		mlx5_mr_free(mr, share_cache->dereg_mr_cb);
 		goto alloc_resources;
 	}
 	MLX5_ASSERT(data.msl == data_re.msl);
@@ -725,7 +725,7 @@ struct mlx5_mr *
 		 * Must be unlocked before calling rte_free() because
 		 * mlx5_mr_mem_event_free_cb() can be called inside.
 		 */
-		mr_free(mr, share_cache->dereg_mr_cb);
+		mlx5_mr_free(mr, share_cache->dereg_mr_cb);
 		return entry->lkey;
 	}
 	/*
@@ -801,7 +801,7 @@ struct mlx5_mr *
 	 * calling rte_free() because mlx5_mr_mem_event_free_cb() can be called
 	 * inside.
 	 */
-	mr_free(mr, share_cache->dereg_mr_cb);
+	mlx5_mr_free(mr, share_cache->dereg_mr_cb);
 	return UINT32_MAX;
 }
 
diff --git a/drivers/common/mlx5/mlx5_common_mr.h b/drivers/common/mlx5/mlx5_common_mr.h
index a2c426d..da0a0f0 100644
--- a/drivers/common/mlx5/mlx5_common_mr.h
+++ b/drivers/common/mlx5/mlx5_common_mr.h
@@ -171,4 +171,8 @@ struct mlx5_mr *
 __rte_internal
 void
 mlx5_common_verbs_dereg_mr(struct mlx5_pmd_mr *pmd_mr);
+
+__rte_internal
+void
+mlx5_mr_free(struct mlx5_mr *mr, mlx5_dereg_mr_t dereg_mr_cb);
 #endif /* RTE_PMD_MLX5_COMMON_MR_H_ */
diff --git a/drivers/common/mlx5/version.map b/drivers/common/mlx5/version.map
index 884001c..f0f3ca9 100644
--- a/drivers/common/mlx5/version.map
+++ b/drivers/common/mlx5/version.map
@@ -63,6 +63,7 @@ INTERNAL {
 	mlx5_mr_lookup_list;
 	mlx5_mr_create_primary;
 	mlx5_mr_flush_local_cache;
+	mlx5_mr_free;
 
 	mlx5_nl_allmulti;
 	mlx5_nl_devlink_family_id_get;
diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
index c308ecc..8b20ee3 100644
--- a/drivers/net/mlx5/mlx5_mr.c
+++ b/drivers/net/mlx5/mlx5_mr.c
@@ -404,7 +404,7 @@ struct mr_update_mp_data {
 		return -1;
 	}
 	LIST_REMOVE(mr, mr);
-	LIST_INSERT_HEAD(&sh->share_cache.mr_free_list, mr, mr);
+	mlx5_mr_free(mr, sh->share_cache.dereg_mr_cb);
 	DEBUG("port %u remove MR(%p) from list", dev->data->port_id,
 	      (void *)mr);
 	mlx5_mr_rebuild_cache(&sh->share_cache);
-- 
1.8.3.1