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net: phy: add device-managed devm_mdiobus_register

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If there's no special ordering requirement for mdiobus_unregister(),
then driver code can be simplified by using a device-managed version
of mdiobus_register(). Prerequisite is that bus allocation has been
done device-managed too. Else mdiobus_free() may be called whilst
bus is still registered, resulting in a BUG_ON(). Therefore let
devm_mdiobus_register() return -EPERM if bus was allocated
non-managed.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Heiner Kallweit 2020-04-20 23:29:05 +02:00 committed by David S. Miller
parent 4406d36dfd
commit 38f961e744
2 changed files with 24 additions and 1 deletions
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8
drivers/net/phy/mdio_bus.c
View File

@ -170,7 +170,12 @@ EXPORT_SYMBOL(mdiobus_alloc_size);
static void _devm_mdiobus_free(struct device *dev, void *res)
{
mdiobus_free(*(struct mii_bus **)res);
struct mii_bus *bus = *(struct mii_bus **)res;
if (bus->is_managed_registered && bus->state == MDIOBUS_REGISTERED)
mdiobus_unregister(bus);
mdiobus_free(bus);
}
static int devm_mdiobus_match(struct device *dev, void *res, void *data)
@ -210,6 +215,7 @@ struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv)
if (bus) {
*ptr = bus;
devres_add(dev, ptr);
bus->is_managed = 1;
} else {
devres_free(ptr);
}

17
include/linux/phy.h
View File

@ -241,6 +241,9 @@ struct mii_bus {
int (*reset)(struct mii_bus *bus);
struct mdio_bus_stats stats[PHY_MAX_ADDR];
unsigned int is_managed:1; /* is device-managed */
unsigned int is_managed_registered:1;
/*
* A lock to ensure that only one thing can read/write
* the MDIO bus at a time
@ -286,6 +289,20 @@ static inline struct mii_bus *mdiobus_alloc(void)
int __mdiobus_register(struct mii_bus *bus, struct module *owner);
#define mdiobus_register(bus) __mdiobus_register(bus, THIS_MODULE)
static inline int devm_mdiobus_register(struct mii_bus *bus)
{
int ret;
if (!bus->is_managed)
return -EPERM;
ret = mdiobus_register(bus);
if (!ret)
bus->is_managed_registered = 1;
return ret;
}
void mdiobus_unregister(struct mii_bus *bus);
void mdiobus_free(struct mii_bus *bus);
struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv);