[PATCH net v4] can: dev: can_fill_info(): don't wake up controller if interface is down

If the interface is down, the CAN controller might be powered down, the
clock disabled, and/or its external reset asserted.

Don't call do_get_berr_counter() to read the CAN bus error counters if
the interface is down. This fixes a generic logic problem that exists
on all platforms.

Fixes: ec56acfef2af1 ("can: flexcan: flexcan_get_berr_counter(): switch on clocks before accessing ecr register")
Cc: stable@vger.kernel.org
Signed-off-by: ChunYuZhiQiang <redacted>
---
v1 -> v2:
  - Reword the commit message to drop the MDIS reasoning.
  - Add Fixes: tag.

v2 -> v3:
  - Use the title and commit message suggested by Bough Chen.
  - Drop the i.MX8QXP-specific crash dump and erratum explanation.
  - Drop the m_can reference.
  - Drop the Link: tag.

v3 -> v4:
  - Move the netif_running() check from the flexcan driver to
    can_fill_info() and can_get_size() in the CAN core, as suggested by
    Marc Kleine-Budde. This covers all CAN drivers, not just flexcan.

 drivers/net/can/dev/netlink.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 6f83b87d54fc..d17f4e9cc144 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c

@@ -584,7 +584,7 @@ static size_t can_get_size(const struct net_device *dev)
 	size += nla_total_size(sizeof(u32));			/* IFLA_CAN_STATE */
 	size += nla_total_size(sizeof(struct can_ctrlmode));	/* IFLA_CAN_CTRLMODE */
 	size += nla_total_size(sizeof(u32));			/* IFLA_CAN_RESTART_MS */
-	if (priv->do_get_berr_counter)				/* IFLA_CAN_BERR_COUNTER */
+	if (priv->do_get_berr_counter && netif_running(dev))	/* IFLA_CAN_BERR_COUNTER */
 		size += nla_total_size(sizeof(struct can_berr_counter));
 	if (priv->termination_const) {
 		size += nla_total_size(sizeof(priv->termination));		/* IFLA_CAN_TERMINATION */

@@ -735,7 +735,7 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	    nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
 	    nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
 
-	    (priv->do_get_berr_counter &&
+	    (priv->do_get_berr_counter && netif_running(dev) &&
 	     !priv->do_get_berr_counter(dev, &bec) &&
 	     nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
 

-- 
2.47.3