staging: rtl8192u: propagate errors in write_nic_byte

Propagate errors from  kzalloc and usb_control_msg and change the
return type of write_nic_byte from void to int.
Signed-off-by: Salah Triki <salah.triki@acm.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8192U.h

@@ -1129,7 +1129,7 @@ int read_nic_byte(struct net_device *dev, int x, u8 *data);
 int read_nic_byte_E(struct net_device *dev, int x, u8 *data);
 int read_nic_dword(struct net_device *dev, int x, u32 *data);
 int read_nic_word(struct net_device *dev, int x, u16 *data);
-void write_nic_byte(struct net_device *dev, int x, u8 y);
+int write_nic_byte(struct net_device *dev, int x, u8 y);
 void write_nic_byte_E(struct net_device *dev, int x, u8 y);
 void write_nic_word(struct net_device *dev, int x, u16 y);
 void write_nic_dword(struct net_device *dev, int x, u32 y);

drivers/staging/rtl8192u/r8192U_core.c

@@ -299,7 +299,7 @@ int read_nic_byte_E(struct net_device *dev, int indx, u8 *data)
 }
 
 /* as 92U has extend page from 4 to 16, so modify functions below. */
-void write_nic_byte(struct net_device *dev, int indx, u8 data)
+int write_nic_byte(struct net_device *dev, int indx, u8 data)
 {
 	int status;
 
@@ -308,7 +308,7 @@ void write_nic_byte(struct net_device *dev, int indx, u8 data)
 	u8 *usbdata = kzalloc(sizeof(data), GFP_KERNEL);
 
 	if (!usbdata)
-		return;
+		return -ENOMEM;
 	*usbdata = data;
 
 	status = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
@@ -317,8 +317,12 @@ void write_nic_byte(struct net_device *dev, int indx, u8 data)
 				 usbdata, 1, HZ / 2);
 	kfree(usbdata);
 
-	if (status < 0)
+	if (status < 0) {
 		netdev_err(dev, "write_nic_byte TimeOut! status: %d\n", status);
+		return status;
+	}
+
+	return 0;
 }