[PATCH 4.19 072/131] mlxsw: Fix some IS_ERR() vs NULL bugs

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

[ Upstream commit c391eb8366ae052d571bb2841f1ccb4d39f3ceb8 ]

The mlxsw_sp_acl_rulei_create() function is supposed to return an error
pointer from mlxsw_afa_block_create().  The problem is that these
functions both return NULL instead of error pointers.  Half the callers
expect NULL and half expect error pointers so it could lead to a NULL
dereference on failure.

This patch changes both of them to return error pointers and changes all
the callers which checked for NULL to check for IS_ERR() instead.

Fixes: 4cda7d8d7098 ("mlxsw: core: Introduce flexible actions support")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c |    4 ++--
 drivers/net/ethernet/mellanox/mlxsw/spectrum2_acl_tcam.c    |    4 ++--
 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl.c          |    3 ++-
 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr_tcam.c      |    4 ++--
 4 files changed, 8 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c
@@ -316,7 +316,7 @@ struct mlxsw_afa_block *mlxsw_afa_block_
 
 	block = kzalloc(sizeof(*block), GFP_KERNEL);
 	if (!block)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	INIT_LIST_HEAD(&block->resource_list);
 	block->afa = mlxsw_afa;
 
@@ -344,7 +344,7 @@ err_second_set_create:
 	mlxsw_afa_set_destroy(block->first_set);
 err_first_set_create:
 	kfree(block);
-	return NULL;
+	return ERR_PTR(-ENOMEM);
 }
 EXPORT_SYMBOL(mlxsw_afa_block_create);
 
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum2_acl_tcam.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum2_acl_tcam.c
@@ -88,8 +88,8 @@ static int mlxsw_sp2_acl_tcam_init(struc
 	 * to be written using PEFA register to all indexes for all regions.
 	 */
 	afa_block = mlxsw_afa_block_create(mlxsw_sp->afa);
-	if (!afa_block) {
-		err = -ENOMEM;
+	if (IS_ERR(afa_block)) {
+		err = PTR_ERR(afa_block);
 		goto err_afa_block;
 	}
 	err = mlxsw_afa_block_continue(afa_block);
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl.c
@@ -442,7 +442,8 @@ mlxsw_sp_acl_rulei_create(struct mlxsw_s
 
 	rulei = kzalloc(sizeof(*rulei), GFP_KERNEL);
 	if (!rulei)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
+
 	rulei->act_block = mlxsw_afa_block_create(acl->mlxsw_sp->afa);
 	if (IS_ERR(rulei->act_block)) {
 		err = PTR_ERR(rulei->act_block);
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_mr_tcam.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_mr_tcam.c
@@ -199,8 +199,8 @@ mlxsw_sp_mr_tcam_afa_block_create(struct
 	int err;
 
 	afa_block = mlxsw_afa_block_create(mlxsw_sp->afa);
-	if (!afa_block)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(afa_block))
+		return afa_block;
 
 	err = mlxsw_afa_block_append_allocated_counter(afa_block,
 						       counter_index);