| Message ID | 20210912120932.993440-5-vladimir.oltean@nxp.com |
|---|---|
| State | New |
| Headers | show |
| Series | Make DSA switch drivers compatible with masters which unregister on shutdown | expand |
On 9/12/2021 5:09 AM, Vladimir Oltean wrote: > Since commit 2f1e8ea726e9 ("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: 60a364760002 ("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>
diff --git a/drivers/net/dsa/microchip/ksz8863_smi.c b/drivers/net/dsa/microchip/ksz8863_smi.c index 11293485138c..5883fa7edda2 100644 --- a/drivers/net/dsa/microchip/ksz8863_smi.c +++ b/drivers/net/dsa/microchip/ksz8863_smi.c @@ -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,
Since commit 2f1e8ea726e9 ("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: 60a364760002 ("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> --- drivers/net/dsa/microchip/ksz8863_smi.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)