[PATCH v2 11/12] can: ems_usb: fix {rx,tx}_errors statistics

[Dario Binacchi <dario.binacchi@amarulasolutions.com>]

The ems_usb_rx_err() function only incremented the receive error counter
and never the transmit error counter, even if the ECC_DIR flag reported
that an error had occurred during transmission. Increment the
receive/transmit error counter based on the value of the ECC_DIR flag.

Fixes: 702171adeed3 ("ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface")
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

---

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

 drivers/net/can/usb/ems_usb.c | 58 ++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 25 deletions(-)

diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 050c0b49938a..5355bac4dccb 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -335,15 +335,14 @@ static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 	struct net_device_stats *stats = &dev->netdev->stats;
 
 	skb = alloc_can_err_skb(dev->netdev, &cf);
-	if (skb == NULL)
-		return;
 
 	if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 		u8 state = msg->msg.can_state;
 
 		if (state & SJA1000_SR_BS) {
 			dev->can.state = CAN_STATE_BUS_OFF;
-			cf->can_id |= CAN_ERR_BUSOFF;
+			if (skb)
+				cf->can_id |= CAN_ERR_BUSOFF;
 
 			dev->can.can_stats.bus_off++;
 			can_bus_off(dev->netdev);
@@ -361,44 +360,53 @@ static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 
 		/* bus error interrupt */
 		dev->can.can_stats.bus_error++;
-		stats->rx_errors++;
 
-		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+		if (skb) {
+			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
-		switch (ecc & SJA1000_ECC_MASK) {
-		case SJA1000_ECC_BIT:
-			cf->data[2] |= CAN_ERR_PROT_BIT;
-			break;
-		case SJA1000_ECC_FORM:
-			cf->data[2] |= CAN_ERR_PROT_FORM;
-			break;
-		case SJA1000_ECC_STUFF:
-			cf->data[2] |= CAN_ERR_PROT_STUFF;
-			break;
-		default:
-			cf->data[3] = ecc & SJA1000_ECC_SEG;
-			break;
+			switch (ecc & SJA1000_ECC_MASK) {
+			case SJA1000_ECC_BIT:
+				cf->data[2] |= CAN_ERR_PROT_BIT;
+				break;
+			case SJA1000_ECC_FORM:
+				cf->data[2] |= CAN_ERR_PROT_FORM;
+				break;
+			case SJA1000_ECC_STUFF:
+				cf->data[2] |= CAN_ERR_PROT_STUFF;
+				break;
+			default:
+				cf->data[3] = ecc & SJA1000_ECC_SEG;
+				break;
+			}
 		}
 
 		/* Error occurred during transmission? */
-		if ((ecc & SJA1000_ECC_DIR) == 0)
-			cf->data[2] |= CAN_ERR_PROT_TX;
+		if ((ecc & SJA1000_ECC_DIR) == 0) {
+			stats->tx_errors++;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_TX;
+		} else {
+			stats->rx_errors++;
+		}
 
-		if (dev->can.state == CAN_STATE_ERROR_WARNING ||
-		    dev->can.state == CAN_STATE_ERROR_PASSIVE) {
+		if (skb && (dev->can.state == CAN_STATE_ERROR_WARNING ||
+			    dev->can.state == CAN_STATE_ERROR_PASSIVE)) {
 			cf->can_id |= CAN_ERR_CRTL;
 			cf->data[1] = (txerr > rxerr) ?
 			    CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 		}
 	} else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
-		cf->can_id |= CAN_ERR_CRTL;
-		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		}
 
 		stats->rx_over_errors++;
 		stats->rx_errors++;
 	}
 
-	netif_rx(skb);
+	if (skb)
+		netif_rx(skb);
 }
 
 /*
-- 
2.43.0