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net: dsa: microchip: ksz8863: be compatible with masters which unregister on shutdown

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Since commit 2f1e8ea726 ("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: 60a3647600 ("net: dsa: microchip: Add Microchip KSZ8863 SMI based driver support")
Link: https://lore.kernel.org/netdev/20210909095324.12978-1-LinoSanfilippo@gmx.de/
Reported-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2021-09-17 16:34:35 +03:00 committed by David S. Miller
parent 46baae56e1
commit fe4053078c
1 changed files with 13 additions and 0 deletions
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13
drivers/net/dsa/microchip/ksz8863_smi.c
View file

@ -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,