Patch "can: m_can: m_can_handle_lec_err(): fix {rx,tx}_errors statistics" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    can: m_can: m_can_handle_lec_err(): fix {rx,tx}_errors statistics

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     can-m_can-m_can_handle_lec_err-fix-rx-tx-_errors-sta.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 42a71e2a802db186e0c3d5f4d86fa6873063b3b8
Author: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
Date:   Fri Nov 22 23:15:47 2024 +0100

    can: m_can: m_can_handle_lec_err(): fix {rx,tx}_errors statistics
    
    [ Upstream commit 988d4222bf9039a875a3d48f2fe35c317831ff68 ]
    
    The m_can_handle_lec_err() function was incorrectly incrementing only the
    receive error counter, even in cases of bit or acknowledgment errors that
    occur during transmission.
    
    Fix the issue by incrementing the appropriate counter based on the
    type of error.
    
    Fixes: e0d1f4816f2a ("can: m_can: add Bosch M_CAN controller support")
    Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
    Link: https://patch.msgid.link/20241122221650.633981-7-dario.binacchi@xxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index e77b4b60f4e61..f28bdb5badd05 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -607,47 +607,60 @@ static int m_can_handle_lec_err(struct net_device *dev,
 	u32 timestamp = 0;
 
 	cdev->can.can_stats.bus_error++;
-	stats->rx_errors++;
 
 	/* propagate the error condition to the CAN stack */
 	skb = alloc_can_err_skb(dev, &cf);
-	if (unlikely(!skb))
-		return 0;
 
 	/* check for 'last error code' which tells us the
 	 * type of the last error to occur on the CAN bus
 	 */
-	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+	if (likely(skb))
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
 	switch (lec_type) {
 	case LEC_STUFF_ERROR:
 		netdev_dbg(dev, "stuff error\n");
-		cf->data[2] |= CAN_ERR_PROT_STUFF;
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
 		break;
 	case LEC_FORM_ERROR:
 		netdev_dbg(dev, "form error\n");
-		cf->data[2] |= CAN_ERR_PROT_FORM;
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_FORM;
 		break;
 	case LEC_ACK_ERROR:
 		netdev_dbg(dev, "ack error\n");
-		cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_ACK;
 		break;
 	case LEC_BIT1_ERROR:
 		netdev_dbg(dev, "bit1 error\n");
-		cf->data[2] |= CAN_ERR_PROT_BIT1;
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
 		break;
 	case LEC_BIT0_ERROR:
 		netdev_dbg(dev, "bit0 error\n");
-		cf->data[2] |= CAN_ERR_PROT_BIT0;
+		stats->tx_errors++;
+		if (likely(skb))
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
 		break;
 	case LEC_CRC_ERROR:
 		netdev_dbg(dev, "CRC error\n");
-		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+		stats->rx_errors++;
+		if (likely(skb))
+			cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
 		break;
 	default:
 		break;
 	}
 
+	if (unlikely(!skb))
+		return 0;
+
 	if (cdev->is_peripheral)
 		timestamp = m_can_get_timestamp(cdev);