Merge branch 'mdio_module_unload'
Ezequiel Garcia says:
====================
net: phy: Prevent an MDIO bus from being unloaded while in use
Changes from v1:
* Dropped the unneeded module_put() on phy_attach_direct().
The motivation of this small series is to fix the current lack of relationship
between an ethernet driver and the MDIO bus behind the PHY device. In such
cases, we would find no visible link between the drivers:
$ lsmod
Module Size Used by Not tainted
mvmdio 2941 0
mvneta 22069 0
Which means nothing prevents the MDIO driver from being removed:
$ modprobe -r mvmdio
# Unable to handle kernel NULL pointer dereference at virtual address 00000060
pgd = c0004000
[00000060] *pgd=00000000
Internal error: Oops: 17 [#1] SMP ARM
Modules linked in: mvneta [last unloaded: mvmdio]
CPU: 0 PID: 22 Comm: kworker/0:1 Not tainted 3.16.0-rc5-01127-g62c0816-dirty #608
Workqueue: events_power_efficient phy_state_machine
task: df5ec840 ti: df67a000 task.ti: df67a000
PC is at phy_state_machine+0x1c/0x468
LR is at phy_state_machine+0x18/0x468
[snip]
This patchset fixes this problem by adding a pair of module_{get,put},
so the module reference count is increased when the PHY device is attached
and is decreased when the PHY is detached.
Tested with mvneta and mv643xx_eth drivers, which depend on the mvmdio
driver to handle MDIO. This series applies on both net and net-next branches.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
