[PATCH v2 06/12] can: m_can: fix {rx,tx}_errors statistics

[Dario Binacchi]

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. The patch fixes 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>

---

Changes in v2:
- Update statistics even if skb allocation fails

 drivers/net/can/m_can/m_can.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 16e9e7d7527d..533bcb77c9f9 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -695,47 +695,60 @@ 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);
 
-- 
2.43.0