can: dev: can_put_echo_skb(): propagate error in case of errors

The function can_put_echo_skb() can fail for several reasons. It may
fail due to OOM, but when it fails it's usually due to locking problems
in the driver.

In order to help developing and debugging of new drivers propagate error
value in case of errors.

Link: https://lore.kernel.org/r/20200915223527.1417033-12-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index dd443e5d8cb730eb9f0d64e26cedd57e5a7373ff..77a5663693af4639da0b4f6d934f90c732154ab0 100644 (file)
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -434,8 +434,8 @@ static void can_flush_echo_skb(struct net_device *dev)
  * of the device driver. The driver must protect access to
  * priv->echo_skb, if necessary.
  */
-void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
-                     unsigned int idx)
+int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
+                    unsigned int idx)
 {
        struct can_priv *priv = netdev_priv(dev);
 
@@ -446,13 +446,13 @@ void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
            (skb->protocol != htons(ETH_P_CAN) &&
             skb->protocol != htons(ETH_P_CANFD))) {
                kfree_skb(skb);
-               return;
+               return 0;
        }
 
        if (!priv->echo_skb[idx]) {
                skb = can_create_echo_skb(skb);
                if (!skb)
-                       return;
+                       return -ENOMEM;
 
                /* make settings for echo to reduce code in irq context */
                skb->pkt_type = PACKET_BROADCAST;
@@ -465,7 +465,10 @@ void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
                /* locking problem with netif_stop_queue() ?? */
                netdev_err(dev, "%s: BUG! echo_skb %d is occupied!\n", __func__, idx);
                kfree_skb(skb);
+               return -EBUSY;
        }
+
+       return 0;
 }
 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 

diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 516892566ac959992325ddb8eee916e20682554e..ed0482b2f4b2fbb420ee6572ead773903d228a03 100644 (file)
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -201,8 +201,8 @@ void can_bus_off(struct net_device *dev);
 void can_change_state(struct net_device *dev, struct can_frame *cf,
                      enum can_state tx_state, enum can_state rx_state);
 
-void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
-                     unsigned int idx);
+int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
+                    unsigned int idx);
 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
                                   u8 *len_ptr);
 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx);