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Commit b184e497 authored by Guenter Roeck's avatar Guenter Roeck Committed by David S. Miller
Browse files

dsa: Fix conversion from host device to mii bus 



Commit b4d2394d ("dsa: Replace mii_bus with a generic host device")
replaces mii_bus with a generic host_dev, and introduces
dsa_host_dev_to_mii_bus() to support conversion from host_dev to mii_bus.
However, in some cases it uses to_mii_bus to perform that conversion.
Since host_dev is not the phy bus device but typically a platform device,
this fails and results in a crash with the affected drivers.

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff81781d35>] __mutex_lock_slowpath+0x75/0x100
PGD 406783067 PUD 406784067 PMD 0
Oops: 0002 [#1] SMP
...
Call Trace:
[<ffffffff810a538b>] ? pick_next_task_fair+0x61b/0x880
[<ffffffff81781de3>] mutex_lock+0x23/0x37
[<ffffffff81533244>] mdiobus_read+0x34/0x60
[<ffffffff8153b95a>] __mv88e6xxx_reg_read+0x8a/0xa0
[<ffffffff8153b9bc>] mv88e6xxx_reg_read+0x4c/0xa0

Fixes: b4d2394d ("dsa: Replace mii_bus with a generic host device")
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Acked-by: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 643566d4

drivers/net/dsa/mv88e6060.c

+12 −4
Original line number Diff line number Diff line
@@ -21,8 +21,12 @@ 


static int reg_read(struct dsa_switch *ds, int addr, int reg)

{

	return mdiobus_read(to_mii_bus(ds->master_dev),

			    ds->pd->sw_addr + addr, reg);

	struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);



	if (bus == NULL)

		return -EINVAL;



	return mdiobus_read(bus, ds->pd->sw_addr + addr, reg);

}



#define REG_READ(addr, reg)					\
@@ -38,8 +42,12 @@ static int reg_read(struct dsa_switch *ds, int addr, int reg) 


static int reg_write(struct dsa_switch *ds, int addr, int reg, u16 val)

{

	return mdiobus_write(to_mii_bus(ds->master_dev),

			     ds->pd->sw_addr + addr, reg, val);

	struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);



	if (bus == NULL)

		return -EINVAL;



	return mdiobus_write(bus, ds->pd->sw_addr + addr, reg, val);

}



#define REG_WRITE(addr, reg, val)				\

drivers/net/dsa/mv88e6xxx.c

+10 −4
Original line number Diff line number Diff line
@@ -75,11 +75,14 @@ int __mv88e6xxx_reg_read(struct mii_bus *bus, int sw_addr, int addr, int reg) 
int mv88e6xxx_reg_read(struct dsa_switch *ds, int addr, int reg)

{

	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);

	struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);

	int ret;



	if (bus == NULL)

		return -EINVAL;



	mutex_lock(&ps->smi_mutex);

	ret = __mv88e6xxx_reg_read(to_mii_bus(ds->master_dev),

				   ds->pd->sw_addr, addr, reg);

	ret = __mv88e6xxx_reg_read(bus, ds->pd->sw_addr, addr, reg);

	mutex_unlock(&ps->smi_mutex);



	return ret;
@@ -119,11 +122,14 @@ int __mv88e6xxx_reg_write(struct mii_bus *bus, int sw_addr, int addr, 
int mv88e6xxx_reg_write(struct dsa_switch *ds, int addr, int reg, u16 val)

{

	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);

	struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);

	int ret;



	if (bus == NULL)

		return -EINVAL;



	mutex_lock(&ps->smi_mutex);

	ret = __mv88e6xxx_reg_write(to_mii_bus(ds->master_dev),

				    ds->pd->sw_addr, addr, reg, val);

	ret = __mv88e6xxx_reg_write(bus, ds->pd->sw_addr, addr, reg, val);

	mutex_unlock(&ps->smi_mutex);



	return ret;