can: peak/pcie_fd: fix potential bug in restarting tx queue

Don't rely on can_get_echo_skb() return value to wake the network tx
queue up: can_get_echo_skb() returns 0 if the echo array slot was not
occupied, but also when the DLC of the released echo frame was 0.

Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/net/can/peak_canfd/peak_canfd.c b/drivers/net/can/peak_canfd/peak_canfd.c
index 85268be0c913..55513411a82e 100644
--- a/drivers/net/can/peak_canfd/peak_canfd.c
+++ b/drivers/net/can/peak_canfd/peak_canfd.c
@@ -258,21 +258,18 @@ static int pucan_handle_can_rx(struct peak_canfd_priv *priv,
         /* if this frame is an echo, */
         if ((rx_msg_flags & PUCAN_MSG_LOOPED_BACK) &&
             !(rx_msg_flags & PUCAN_MSG_SELF_RECEIVE)) {
-                int n;
                 unsigned long flags;
 
                 spin_lock_irqsave(&priv->echo_lock, flags);
-                n = can_get_echo_skb(priv->ndev, msg->client);
+                can_get_echo_skb(priv->ndev, msg->client);
                 spin_unlock_irqrestore(&priv->echo_lock, flags);
 
                 /* count bytes of the echo instead of skb */
                 stats->tx_bytes += cf_len;
                 stats->tx_packets++;
 
-                if (n) {
-                        /* restart tx queue only if a slot is free */
-                        netif_wake_queue(priv->ndev);
-                }
+                /* restart tx queue (a slot is free) */
+                netif_wake_queue(priv->ndev);
 
                 return 0;
         }