[PATCH v2 2/3] s390/netiucv: Fix return type of netiucv_tx()

Nathan Chancellor
2022-11-03T17:01:53Z

drivers/s390/net/netiucv.c:1854:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
.ndo_start_xmit = netiucv_tx,
^~~~~~~~~~

->ndo_start_xmit() in 'struct net_device_ops' expects a return type of
'netdev_tx_t', not 'int'. Adjust the return type of netiucv_tx() to
match the prototype's to resolve the warning and potential CFI failure,
should s390 select ARCH_SUPPORTS_CFI_CLANG in the future.

Additionally, while in the area, remove a comment block that is no
longer relevant.

Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
v2:
- Pick up tags from Alexandra and Kees.
- Remove comment block above netiucv_tx() (Alexandra).
v1: https://lore.kernel.org/20221102163252.49175-2-nathan@kernel.org/
---
drivers/s390/net/netiucv.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
index 65aa0a96c21d..66076cada8ae 100644
--- a/drivers/s390/net/netiucv.c
+++ b/drivers/s390/net/netiucv.c
@@ -1248,15 +1248,8 @@ static int netiucv_close(struct net_device *dev)
/*
* Start transmission of a packet.
* Called from generic network device layer.
- *
- * @param skb Pointer to buffer containing the packet.
- * @param dev Pointer to interface struct.
- *
- * @return 0 if packet consumed, !0 if packet rejected.
- * Note: If we return !0, then the packet is free'd by
- * the generic network layer.
*/
-static int netiucv_tx(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t netiucv_tx(struct sk_buff *skb, struct net_device *dev)
{
struct netiucv_priv *privptr = netdev_priv(dev);
int rc;
--
2.38.1