[PATCH v3] staging: octeon: Fix return type of cvm_oct_xmit and cvm_oct_xmit_pow

Nathan Huckleberry
2022-09-14T21:11:43Z

The ndo_start_xmit field in net_device_ops is expected to be of type
netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb, struct net_device *dev).

The mismatched return type breaks forward edge kCFI since the underlying
function definition does not match the function hook definition.

The return type of cvm_oct_xmit and cvm_oct_xmit_pow should be changed
from int to netdev_tx_t.

Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1703
Cc: llvm@lists.linux.dev
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

---

Changes v1 -> v2:
- Update function signatures in ethernet-tx.h.

Changes v2 -> v3:
- Move changes below the scissors --- so they don't show in commit msg
- Add reviewed-by tag

drivers/staging/octeon/ethernet-tx.c | 4 ++--
drivers/staging/octeon/ethernet-tx.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/octeon/ethernet-tx.c b/drivers/staging/octeon/ethernet-tx.c
index 1ad94c5060b5..a36e36701c74 100644
--- a/drivers/staging/octeon/ethernet-tx.c
+++ b/drivers/staging/octeon/ethernet-tx.c
@@ -125,7 +125,7 @@ static void cvm_oct_free_tx_skbs(struct net_device *dev)
*
* Returns Always returns NETDEV_TX_OK
*/
-int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
+netdev_tx_t cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
{
union cvmx_pko_command_word0 pko_command;
union cvmx_buf_ptr hw_buffer;
@@ -506,7 +506,7 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
* @dev: Device info structure
* Returns Always returns zero
*/
-int cvm_oct_xmit_pow(struct sk_buff *skb, struct net_device *dev)
+netdev_tx_t cvm_oct_xmit_pow(struct sk_buff *skb, struct net_device *dev)
{
struct octeon_ethernet *priv = netdev_priv(dev);
void *packet_buffer;
diff --git a/drivers/staging/octeon/ethernet-tx.h b/drivers/staging/octeon/ethernet-tx.h
index 78936e9b33b0..6c524668f65a 100644
--- a/drivers/staging/octeon/ethernet-tx.h
+++ b/drivers/staging/octeon/ethernet-tx.h
@@ -5,8 +5,8 @@
* Copyright (c) 2003-2007 Cavium Networks
*/

-int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev);
-int cvm_oct_xmit_pow(struct sk_buff *skb, struct net_device *dev);
+netdev_tx_t cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev);
+netdev_tx_t cvm_oct_xmit_pow(struct sk_buff *skb, struct net_device *dev);
int cvm_oct_transmit_qos(struct net_device *dev, void *work_queue_entry,
int do_free, int qos);
void cvm_oct_tx_initialize(void);
--
2.37.2.789.g6183377224-goog