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author | Sergey Ryazanov <ryazanov.s.a@gmail.com> | 2021-06-22 01:50:57 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2021-06-22 10:01:16 -0700 |
commit | 9f0248ea476ee59d336d7c8bf1a5d0919d93d030 (patch) | |
tree | a012e1c1b0cd41284f25628478910cf3babdef03 | |
parent | 322a0ba99c50d6abadeda709f0552eb8dac6668c (diff) | |
download | linux-stable-9f0248ea476ee59d336d7c8bf1a5d0919d93d030.tar.gz linux-stable-9f0248ea476ee59d336d7c8bf1a5d0919d93d030.tar.bz2 linux-stable-9f0248ea476ee59d336d7c8bf1a5d0919d93d030.zip |
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>
-rw-r--r-- | drivers/net/mhi/net.c | 3 | ||||
-rw-r--r-- | drivers/net/wwan/wwan_core.c | 10 | ||||
-rw-r--r-- | drivers/net/wwan/wwan_hwsim.c | 1 | ||||
-rw-r--r-- | include/linux/wwan.h | 2 |
4 files changed, 1 insertions, 15 deletions
diff --git a/drivers/net/mhi/net.c b/drivers/net/mhi/net.c index 6aa753387372..ffd1c01b3f35 100644 --- a/drivers/net/mhi/net.c +++ b/drivers/net/mhi/net.c @@ -383,7 +383,6 @@ static void mhi_net_dellink(void *ctxt, struct net_device *ndev, } static const struct wwan_ops mhi_wwan_ops = { - .owner = THIS_MODULE, .priv_size = sizeof(struct mhi_net_dev), .setup = mhi_net_setup, .newlink = mhi_net_newlink, @@ -436,7 +435,7 @@ static void mhi_net_remove(struct mhi_device *mhi_dev) struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); struct mhi_controller *cntrl = mhi_dev->mhi_cntrl; - /* rtnetlink takes care of removing remaining links */ + /* WWAN core takes care of removing remaining links */ wwan_unregister_ops(&cntrl->mhi_dev->dev); if (create_default_iface) 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); } diff --git a/drivers/net/wwan/wwan_hwsim.c b/drivers/net/wwan/wwan_hwsim.c index c1e850b9c087..a8582a58a385 100644 --- a/drivers/net/wwan/wwan_hwsim.c +++ b/drivers/net/wwan/wwan_hwsim.c @@ -94,7 +94,6 @@ static void wwan_hwsim_netdev_setup(struct net_device *ndev) } static const struct wwan_ops wwan_hwsim_wwan_rtnl_ops = { - .owner = THIS_MODULE, .priv_size = 0, /* No private data */ .setup = wwan_hwsim_netdev_setup, }; diff --git a/include/linux/wwan.h b/include/linux/wwan.h index 34222230360c..e1981ea3a2fd 100644 --- a/include/linux/wwan.h +++ b/include/linux/wwan.h @@ -128,14 +128,12 @@ void *wwan_port_get_drvdata(struct wwan_port *port); /** * struct wwan_ops - WWAN device ops - * @owner: module owner of the WWAN ops * @priv_size: size of private netdev data area * @setup: set up a new netdev * @newlink: register the new netdev * @dellink: remove the given netdev */ struct wwan_ops { - struct module *owner; unsigned int priv_size; void (*setup)(struct net_device *dev); int (*newlink)(void *ctxt, struct net_device *dev, |