can: fix NOHZ local_softirq_pending 08 warning

When using nanosleep() in an userspace application we get a ratelimit warning NOHZ: local_softirq_pending 08 for 10 times. The echo of CAN frames is done from process context and softirq context only. Therefore the usage of netif_rx() was wrong (for years). This patch replaces netif_rx() with netif_rx_ni() which has to be used from process/softirq context. It also adds a missing comment that can_send() must no be used from hardirq context. Signed-off-by: Oliver Hartkopp <[email protected]> Signed-off-by: Urs Thuermann <[email protected]> Signed-off-by: David S. Miller <[email protected]>
mrcsosa · Sep 15, 2009 · 481a819 · 481a819
1 parent 0b6a05c
commit 481a819
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
@@ -80,7 +80,7 @@ static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 	skb->dev       = dev;
 	skb->ip_summed = CHECKSUM_UNNECESSARY;
 
-	netif_rx(skb);
+	netif_rx_ni(skb);
 }
 
 static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)

diff --git a/net/can/af_can.c b/net/can/af_can.c
@@ -199,6 +199,8 @@ static int can_create(struct net *net, struct socket *sock, int protocol)
  * @skb: pointer to socket buffer with CAN frame in data section
  * @loop: loopback for listeners on local CAN sockets (recommended default!)
  *
+ * Due to the loopback this routine must not be called from hardirq context.
+ *
  * Return:
  *  0 on success
  *  -ENETDOWN when the selected interface is down
@@ -278,7 +280,7 @@ int can_send(struct sk_buff *skb, int loop)
 	}
 
 	if (newskb)
-		netif_rx(newskb);
+		netif_rx_ni(newskb);
 
 	/* update statistics */
 	can_stats.tx_frames++;