Revert "RDMA/mlx5: Fix releasing unallocated memory in dereg MR flow"

commit 4163cb3 upstream.

This patch is not the full fix and still causes to call traces
during mlx5_ib_dereg_mr().

This reverts commit f0ae4af.

Fixes: f0ae4af ("RDMA/mlx5: Fix releasing unallocated memory in dereg MR flow")
Link: https://lore.kernel.org/r/20211222101312.1358616-1-maorg@nvidia.com
Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Acked-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -641,6 +641,7 @@ struct mlx5_ib_mr {
 
 	/* User MR data */
 	struct mlx5_cache_ent *cache_ent;
+	struct ib_umem *umem;
 
 	/* This is zero'd when the MR is allocated */
 	union {
@@ -652,7 +653,7 @@ struct mlx5_ib_mr {
 			struct list_head list;
 		};
 
-		/* Used only by kernel MRs */
+		/* Used only by kernel MRs (umem == NULL) */
 		struct {
 			void *descs;
 			void *descs_alloc;
@@ -674,9 +675,8 @@ struct mlx5_ib_mr {
 			int data_length;
 		};
 
-		/* Used only by User MRs */
+		/* Used only by User MRs (umem != NULL) */
 		struct {
-			struct ib_umem *umem;
 			unsigned int page_shift;
 			/* Current access_flags */
 			int access_flags;

drivers/infiniband/hw/mlx5/mr.c

@@ -1911,18 +1911,19 @@ mlx5_alloc_priv_descs(struct ib_device *device,
 	return ret;
 }
 
-static void mlx5_free_priv_descs(struct mlx5_ib_mr *mr)
+static void
+mlx5_free_priv_descs(struct mlx5_ib_mr *mr)
 {
-	struct mlx5_ib_dev *dev = to_mdev(mr->ibmr.device);
-	int size = mr->max_descs * mr->desc_size;
-
-	if (!mr->descs)
-		return;
+	if (!mr->umem && mr->descs) {
+		struct ib_device *device = mr->ibmr.device;
+		int size = mr->max_descs * mr->desc_size;
+		struct mlx5_ib_dev *dev = to_mdev(device);
 
-	dma_unmap_single(&dev->mdev->pdev->dev, mr->desc_map, size,
-			 DMA_TO_DEVICE);
-	kfree(mr->descs_alloc);
-	mr->descs = NULL;
+		dma_unmap_single(&dev->mdev->pdev->dev, mr->desc_map, size,
+				 DMA_TO_DEVICE);
+		kfree(mr->descs_alloc);
+		mr->descs = NULL;
+	}
 }
 
 int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
@@ -1998,8 +1999,7 @@ int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 	if (mr->cache_ent) {
 		mlx5_mr_cache_free(dev, mr);
 	} else {
-		if (!udata)
-			mlx5_free_priv_descs(mr);
+		mlx5_free_priv_descs(mr);
 		kfree(mr);
 	}
 	return 0;
@@ -2086,6 +2086,7 @@ static struct mlx5_ib_mr *mlx5_ib_alloc_pi_mr(struct ib_pd *pd,
 	if (err)
 		goto err_free_in;
 
+	mr->umem = NULL;
 	kfree(in);
 
 	return mr;
@@ -2212,6 +2213,7 @@ static struct ib_mr *__mlx5_ib_alloc_mr(struct ib_pd *pd,
 	}
 
 	mr->ibmr.device = pd->device;
+	mr->umem = NULL;
 
 	switch (mr_type) {
 	case IB_MR_TYPE_MEM_REG: