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| author | Sergey Ryazanov <ryazanov.s.a@gmail.com> | 2021-06-22 01:50:57 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-06-22 20:01:16 +0300 |
| commit | 9f0248ea476ee59d336d7c8bf1a5d0919d93d030 (patch) | |
| tree | a012e1c1b0cd41284f25628478910cf3babdef03 /drivers/net/wwan/wwan_core.c | |
| parent | 322a0ba99c50d6abadeda709f0552eb8dac6668c (diff) | |
| download | linux-9f0248ea476ee59d336d7c8bf1a5d0919d93d030.tar.xz | |
wwan: core: no more hold netdev ops owning module
The WWAN netdev ops owner holding was used to protect from the
unexpected memory disappear. This approach causes a dependency cycle
(driver -> core -> driver) and effectively prevents a WWAN driver
unloading. E.g. WWAN hwsim could not be unloaded until all simulated
devices are removed:
~# modprobe wwan_hwsim devices=2
~# lsmod | grep wwan
wwan_hwsim 16384 2
wwan 20480 1 wwan_hwsim
~# rmmod wwan_hwsim
rmmod: ERROR: Module wwan_hwsim is in use
~# echo > /sys/kernel/debug/wwan_hwsim/hwsim0/destroy
~# echo > /sys/kernel/debug/wwan_hwsim/hwsim1/destroy
~# lsmod | grep wwan
wwan_hwsim 16384 0
wwan 20480 1 wwan_hwsim
~# rmmod wwan_hwsim
For a real device driver this will cause an inability to unload module
until a served device is physically detached.
Since the last commit we are removing all child netdev(s) when a driver
unregister the netdev ops. This allows us to permit the driver
unloading, since any sane driver will call ops unregistering on a device
deinitialization. So, remove the holding of an ops owner to make it
easier to unload a driver module. The owner field has also beed removed
from the ops structure as there are no more users of this field.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/wwan/wwan_core.c')
| -rw-r--r-- | drivers/net/wwan/wwan_core.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index ec6a69b23dd1..b634a0ba1196 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -929,11 +929,6 @@ int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, return -EBUSY; } - if (!try_module_get(ops->owner)) { - wwan_remove_dev(wwandev); - return -ENODEV; - } - wwandev->ops = ops; wwandev->ops_ctxt = ctxt; @@ -960,7 +955,6 @@ static int wwan_child_dellink(struct device *dev, void *data) void wwan_unregister_ops(struct device *parent) { struct wwan_device *wwandev = wwan_dev_get_by_parent(parent); - struct module *owner; LIST_HEAD(kill_list); if (WARN_ON(IS_ERR(wwandev))) @@ -976,8 +970,6 @@ void wwan_unregister_ops(struct device *parent) */ put_device(&wwandev->dev); - owner = wwandev->ops->owner; /* Preserve ops owner */ - rtnl_lock(); /* Prevent concurent netdev(s) creation/destroying */ /* Remove all child netdev(s), using batch removing */ @@ -989,8 +981,6 @@ void wwan_unregister_ops(struct device *parent) rtnl_unlock(); - module_put(owner); - wwandev->ops_ctxt = NULL; wwan_remove_dev(wwandev); } |