On 04/18/2018 05:00 PM, Andrew Lunn wrote:
> mdiobus_register will search for any mdiobus board info registered for
> the bus being registered. If found, it will probe devices on the bus.
> That device, if for example it is an ethernet switch, may then try to
> register an mdio bus. Thus we need to allow recursive calls to
> mdiobus_register.
>
> Holding the mdio_board_lock will cause a deadlock during this
> recursion. Release the lock and use list_for_each_entry_safe.
>
> Signed-off-by: Andrew Lunn <and...@lunn.ch>
> ---
> drivers/net/phy/mdio-boardinfo.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/mdio-boardinfo.c
> b/drivers/net/phy/mdio-boardinfo.c
> index 1861f387820d..863496fa5d13 100644
> --- a/drivers/net/phy/mdio-boardinfo.c
> +++ b/drivers/net/phy/mdio-boardinfo.c
> @@ -30,17 +30,20 @@ void mdiobus_setup_mdiodev_from_board_info(struct mii_bus
> *bus,
> struct mdio_board_info *bi))
> {
> struct mdio_board_entry *be;
> + struct mdio_board_entry *tmp;
> struct mdio_board_info *bi;
> int ret;
>
> mutex_lock(&mdio_board_lock);
Don't you need to drop that lock here?
> - list_for_each_entry(be, &mdio_board_list, list) {
> + list_for_each_entry_safe(be, tmp, &mdio_board_list, list) {
> bi = &be->board_info;
>
> if (strcmp(bus->id, bi->bus_id))
> continue;
>
> + mutex_unlock(&mdio_board_lock);
> ret = cb(bus, bi);
> + mutex_lock(&mdio_board_lock);
> if (ret)
> continue;
>
And conversely drop the unlock from the end of this function?
Also, would you rather target "net" for this change since this appears
to be a bug fix?
--
Florian
