Commit fe405307 authored by Vladimir Oltean's avatar Vladimir Oltean Committed by David S. Miller
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net: dsa: microchip: ksz8863: be compatible with masters which unregister on shutdown 

Since commit 2f1e8ea7 ("net: dsa: link interfaces with the DSA
master to get rid of lockdep warnings"), DSA gained a requirement which
it did not fulfill, which is to unlink itself from the DSA master at
shutdown time.

Since the Microchip sub-driver for KSZ8863 was introduced after the bad
commit, it has never worked with DSA masters which decide to unregister
their net_device on shutdown, effectively hanging the reboot process.
To fix that, we need to call dsa_switch_shutdown.

Since this driver expects the MDIO bus to be backed by mdio_bitbang, I
don't think there is currently any MDIO bus driver which implements its
->shutdown by redirecting it to ->remove, but in any case, to be
compatible with that pattern, it is necessary to implement an "if this
then not that" scheme, to avoid ->remove and ->shutdown from being
called both for the same struct device.

Fixes: 60a36476 ("net: dsa: microchip: Add Microchip KSZ8863 SMI based driver support")
Link: https://lore.kernel.org/netdev/20210909095324.12978-1-LinoSanfilippo@gmx.de/


Reported-by: default avatarLino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 46baae56

drivers/net/dsa/microchip/ksz8863_smi.c

+13 −0
Original line number Diff line number Diff line
@@ -191,6 +191,18 @@ static void ksz8863_smi_remove(struct mdio_device *mdiodev) 


	if (dev)

		ksz_switch_remove(dev);



	dev_set_drvdata(&mdiodev->dev, NULL);

}



static void ksz8863_smi_shutdown(struct mdio_device *mdiodev)

{

	struct ksz_device *dev = dev_get_drvdata(&mdiodev->dev);



	if (dev)

		dsa_switch_shutdown(dev->ds);



	dev_set_drvdata(&mdiodev->dev, NULL);

}



static const struct of_device_id ksz8863_dt_ids[] = {
@@ -203,6 +215,7 @@ MODULE_DEVICE_TABLE(of, ksz8863_dt_ids); 
static struct mdio_driver ksz8863_driver = {

	.probe	= ksz8863_smi_probe,

	.remove	= ksz8863_smi_remove,

	.shutdown = ksz8863_smi_shutdown,

	.mdiodrv.driver = {

		.name	= "ksz8863-switch",

		.of_match_table = ksz8863_dt_ids,