[PATCH v3] staging: rtl8712: Fix return type for implementation of ndo_start_xmit

[GUO Zihua <guozihua@huawei.com>]

CFI (Control Flow Integrity) is a safety feature allowing the system to
detect and react should a potential control flow hijacking occurs. In
particular, the Forward-Edge CFI protects indirect function calls by
ensuring the prototype of function that is actually called matches the
definition of the function hook.

Since Linux now supports CFI, it will be a good idea to fix mismatched
return type for implementation of hooks. Otherwise this would get
cought out by CFI and cause a panic.

Use enums from netdev_tx_t as return value instead, then change return
type to netdev_tx_t.

Signed-off-by: GUO Zihua <guozihua@huawei.com>
---

v3:
  Provide detail on CFI.

v2:
  Fix truncated subject.

---
 drivers/staging/rtl8712/xmit_linux.c | 6 +++---
 drivers/staging/rtl8712/xmit_osdep.h | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/rtl8712/xmit_linux.c b/drivers/staging/rtl8712/xmit_linux.c
index 4a93839bf947..e84b9fa231cd 100644
--- a/drivers/staging/rtl8712/xmit_linux.c
+++ b/drivers/staging/rtl8712/xmit_linux.c
@@ -140,7 +140,7 @@ void r8712_xmit_complete(struct _adapter *padapter, struct xmit_frame *pxframe)
 	pxframe->pkt = NULL;
 }
 
-int r8712_xmit_entry(_pkt *pkt, struct  net_device *netdev)
+netdev_tx_t r8712_xmit_entry(_pkt *pkt, struct  net_device *netdev)
 {
 	struct xmit_frame *xmitframe = NULL;
 	struct _adapter *adapter = netdev_priv(netdev);
@@ -165,11 +165,11 @@ int r8712_xmit_entry(_pkt *pkt, struct  net_device *netdev)
 	}
 	xmitpriv->tx_pkts++;
 	xmitpriv->tx_bytes += xmitframe->attrib.last_txcmdsz;
-	return 0;
+	return NETDEV_TX_OK;
 _xmit_entry_drop:
 	if (xmitframe)
 		r8712_free_xmitframe(xmitpriv, xmitframe);
 	xmitpriv->tx_drop++;
 	dev_kfree_skb_any(pkt);
-	return 0;
+	return NETDEV_TX_OK;
 }
diff --git a/drivers/staging/rtl8712/xmit_osdep.h b/drivers/staging/rtl8712/xmit_osdep.h
index b76021b568f8..1ad42658c883 100644
--- a/drivers/staging/rtl8712/xmit_osdep.h
+++ b/drivers/staging/rtl8712/xmit_osdep.h
@@ -34,7 +34,7 @@ struct sta_xmit_priv;
 struct xmit_frame;
 struct xmit_buf;
 
-int r8712_xmit_entry(_pkt *pkt, struct  net_device *pnetdev);
+netdev_tx_t r8712_xmit_entry(_pkt *pkt, struct  net_device *pnetdev);
 void r8712_SetFilter(struct work_struct *work);
 int r8712_xmit_resource_alloc(struct _adapter *padapter,
 			      struct xmit_buf *pxmitbuf);
-- 
2.17.1