iavf: prevent accidental free of filter structure

stable inclusion
form stable-v5.10.82
commit ddcc185baa2b8bbb7af2d39a4ba1ce8bc54a38e5
bugzilla: 185877 https://gitee.com/openeuler/kernel/issues/I4QU6V

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ddcc185baa2b8bbb7af2d39a4ba1ce8bc54a38e5

--------------------------------

[ Upstream commit 4f040080 ]

In iavf_config_clsflower, the filter structure could be accidentally
released at the end, if iavf_parse_cls_flower or iavf_handle_tclass ever
return a non-zero but positive value.

In this case, the function continues through to the end, and will call
kfree() on the filter structure even though it has been added to the
linked list.

This can actually happen because iavf_parse_cls_flower will return
a positive IAVF_ERR_CONFIG value instead of the traditional negative
error codes.

Fix this by ensuring that the kfree() check and error checks are
similar. Use the more idiomatic "if (err)" to catch all non-zero error
codes.

Fixes: 0075fa0f ("i40evf: Add support to apply cloud filters")
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Tested-by: NTony Brelinski <tony.brelinski@intel.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -3027,11 +3027,11 @@ static int iavf_configure_clsflower(struct iavf_adapter *adapter,
 	/* start out with flow type and eth type IPv4 to begin with */
 	filter->f.flow_type = VIRTCHNL_TCP_V4_FLOW;
 	err = iavf_parse_cls_flower(adapter, cls_flower, filter);
-	if (err < 0)
+	if (err)
 		goto err;
 
 	err = iavf_handle_tclass(adapter, tc, filter);
-	if (err < 0)
+	if (err)
 		goto err;
 
 	/* add filter to the list */