Merge tag 'linux-can-fixes-for-6.0-20220921' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2022-09-21

The 1st patch is by me, targets the flexcan driver and fixes a
potential system hang on single core systems under high CAN packet
rate.

The next 2 patches are also by me and target the gs_usb driver. A
potential race condition during the ndo_open callback as well as the
return value if the ethtool identify feature is not supported are
fixed.

* tag 'linux-can-fixes-for-6.0-20220921' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  can: gs_usb: gs_usb_set_phys_id(): return with error if identify is not supported
  can: gs_usb: gs_can_open(): fix race dev->can.state condition
  can: flexcan: flexcan_mailbox_read() fix return value for drop = true
====================

Link: https://lore.kernel.org/r/20220921083609.419768-1-mkl@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 18 insertions, 13 deletions

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index f857968efed7d..ccb438eca517d 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -941,11 +941,6 @@ static struct sk_buff *flexcan_mailbox_read(struct can_rx_offload *offload,
 	u32 reg_ctrl, reg_id, reg_iflag1;
 	int i;
 
-	if (unlikely(drop)) {
-		skb = ERR_PTR(-ENOBUFS);
-		goto mark_as_read;
-	}
-
 	mb = flexcan_get_mb(priv, n);
 
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX) {
@@ -974,6 +969,11 @@ static struct sk_buff *flexcan_mailbox_read(struct can_rx_offload *offload,
 		reg_ctrl = priv->read(&mb->can_ctrl);
 	}
 
+	if (unlikely(drop)) {
+		skb = ERR_PTR(-ENOBUFS);
+		goto mark_as_read;
+	}
+
 	if (reg_ctrl & FLEXCAN_MB_CNT_EDL)
 		skb = alloc_canfd_skb(offload->dev, &cfd);
 	else
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index baf749c8cda3f..c1ff3c046d62c 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -824,6 +824,7 @@ static int gs_can_open(struct net_device *netdev)
 		flags |= GS_CAN_MODE_TRIPLE_SAMPLE;
 
 	/* finally start device */
+	dev->can.state = CAN_STATE_ERROR_ACTIVE;
 	dm->mode = cpu_to_le32(GS_CAN_MODE_START);
 	dm->flags = cpu_to_le32(flags);
 	rc = usb_control_msg(interface_to_usbdev(dev->iface),
@@ -835,13 +836,12 @@ static int gs_can_open(struct net_device *netdev)
 	if (rc < 0) {
 		netdev_err(netdev, "Couldn't start device (err=%d)\n", rc);
 		kfree(dm);
+		dev->can.state = CAN_STATE_STOPPED;
 		return rc;
 	}
 
 	kfree(dm);
 
-	dev->can.state = CAN_STATE_ERROR_ACTIVE;
-
 	parent->active_channels++;
 	if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
 		netif_start_queue(netdev);
@@ -925,17 +925,21 @@ static int gs_usb_set_identify(struct net_device *netdev, bool do_identify)
 }
 
 /* blink LED's for finding the this interface */
-static int gs_usb_set_phys_id(struct net_device *dev,
+static int gs_usb_set_phys_id(struct net_device *netdev,
 			      enum ethtool_phys_id_state state)
 {
+	const struct gs_can *dev = netdev_priv(netdev);
 	int rc = 0;
 
+	if (!(dev->feature & GS_CAN_FEATURE_IDENTIFY))
+		return -EOPNOTSUPP;
+
 	switch (state) {
 	case ETHTOOL_ID_ACTIVE:
-		rc = gs_usb_set_identify(dev, GS_CAN_IDENTIFY_ON);
+		rc = gs_usb_set_identify(netdev, GS_CAN_IDENTIFY_ON);
 		break;
 	case ETHTOOL_ID_INACTIVE:
-		rc = gs_usb_set_identify(dev, GS_CAN_IDENTIFY_OFF);
+		rc = gs_usb_set_identify(netdev, GS_CAN_IDENTIFY_OFF);
 		break;
 	default:
 		break;
@@ -1072,9 +1076,10 @@ static struct gs_can *gs_make_candev(unsigned int channel,
 		dev->feature |= GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX |
 			GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO;
 
-	if (le32_to_cpu(dconf->sw_version) > 1)
-		if (feature & GS_CAN_FEATURE_IDENTIFY)
-			netdev->ethtool_ops = &gs_usb_ethtool_ops;
+	/* GS_CAN_FEATURE_IDENTIFY is only supported for sw_version > 1 */
+	if (!(le32_to_cpu(dconf->sw_version) > 1 &&
+	      feature & GS_CAN_FEATURE_IDENTIFY))
+		dev->feature &= ~GS_CAN_FEATURE_IDENTIFY;
 
 	kfree(bt_const);