On 27/04/16 12:49, Andrew Lunn wrote:
> On Wed, Apr 27, 2016 at 03:30:57PM -0400, Vivien Didelot wrote:
>> Hi David, All,
>>
>> Sergei Shtylyov <sergei.shtyl...@cogentembedded.com> writes:
>>
>>> Arnd Bergmann asked that get_phy_device() returns either NULL or the error
>>> value, not both on error. Do as he said, return ERR_PTR(-ENODEV) instead
>>> of NULL when the PHY ID registers read as all ones.
>>>
>>> Suggested-by: Arnd Bergmann <a...@arndb.de>
>>> Signed-off-by: Sergei Shtylyov <sergei.shtyl...@cogentembedded.com>
>>>
>>> ---
>>> drivers/net/phy/phy_device.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> Index: net-next/drivers/net/phy/phy_device.c
>>> ===================================================================
>>> --- net-next.orig/drivers/net/phy/phy_device.c
>>> +++ net-next/drivers/net/phy/phy_device.c
>>> @@ -529,7 +529,7 @@ struct phy_device *get_phy_device(struct
>>>
>>> /* If the phy_id is mostly Fs, there is no device there */
>>> if ((phy_id & 0x1fffffff) == 0x1fffffff)
>>> - return NULL;
>>> + return ERR_PTR(-ENODEV);
>>>
>>> return phy_device_create(bus, addr, phy_id, is_c45, &c45_ids);
>>> }
>
> This change is wrong, it needs reverting, or the call sights need
> fixing to expect ENODEV.
>
> The point is, the device not being there is not an error, with respect
> to the code calling this function.
>
> It gets called by mdiobus_scan()
>
> struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
> {
> struct phy_device *phydev;
> int err;
>
> phydev = get_phy_device(bus, addr, false);
> if (IS_ERR(phydev) || phydev == NULL)
> return phydev;
>
> So before, we return NULL, if the device was not there. Now we return
> ERR_PTR(-ENODEV).
>
> This is being called by:
>
> int __mdiobus_register(struct mii_bus *bus, struct module *owner)
> {
> struct mdio_device *mdiodev;
> ...
> for (i = 0; i < PHY_MAX_ADDR; i++) {
> if ((bus->phy_mask & (1 << i)) == 0) {
> struct phy_device *phydev;
>
> phydev = mdiobus_scan(bus, i);
> if (IS_ERR(phydev)) {
> err = PTR_ERR(phydev);
> goto error;
> }
> }
> }
>
> This is treating ERR_PTR(-ENODEV) as a fatal error, where as before
> IS_ERR(NULL) would be false and it would continue scanning other
> addresses on the bus.
>
> Please revert this, or fix all the callsites such that ENODEV is not a
> fatal error.
So the one you pointed out in __mdiobus_register() is definitively
needed, though I did get a different issue than Vivien's (-EBUSY vs.
-EINVAL). The get_phy_device() in drivers/of/of_mdio.c probably needs
something similar too, here is what I locally have for the moment:
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 499003ee8055..94a27b028dd8 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -333,7 +333,7 @@ int __mdiobus_register(struct mii_bus *bus, struct
module *owner)
struct phy_device *phydev;
phydev = mdiobus_scan(bus, i);
- if (IS_ERR(phydev)) {
+ if (IS_ERR(phydev) && PTR_ERR(phydev) != -ENODEV) {
err = PTR_ERR(phydev);
goto error;
}
--
Florian
