[PATCH net-next] netdevsim: Forbid devlink reload when adding or deleting ports

Leon Romanovsky
2021-08-05T11:02:55Z

From: Leon Romanovsky <leonro@nvidia.com>

In order to remove complexity in devlink core related to
devlink_reload_enable/disable, let's rewrite new_port/del_port
logic to rely on internal to netdevsim lcok.

We should protect only reload_down flow because it destroys nsim_dev,
which is needed for nsim_dev_port_add/nsim_dev_port_del to hold
port_list_lock.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/net/netdevsim/bus.c | 16 ++++------------
drivers/net/netdevsim/dev.c | 7 +++++++
2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
index ff01e5bdc72e..a29ec264119d 100644
--- a/drivers/net/netdevsim/bus.c
+++ b/drivers/net/netdevsim/bus.c
@@ -183,8 +183,6 @@ new_port_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct nsim_bus_dev *nsim_bus_dev = to_nsim_bus_dev(dev);
- struct nsim_dev *nsim_dev = dev_get_drvdata(dev);
- struct devlink *devlink;
unsigned int port_index;
int ret;

@@ -195,12 +193,10 @@ new_port_store(struct device *dev, struct device_attribute *attr,
if (ret)
return ret;

- devlink = priv_to_devlink(nsim_dev);
+ if (!mutex_trylock(&nsim_bus_dev->nsim_bus_reload_lock))
+ return -EBUSY;

- mutex_lock(&nsim_bus_dev->nsim_bus_reload_lock);
- devlink_reload_disable(devlink);
ret = nsim_dev_port_add(nsim_bus_dev, NSIM_DEV_PORT_TYPE_PF, port_index);
- devlink_reload_enable(devlink);
mutex_unlock(&nsim_bus_dev->nsim_bus_reload_lock);
return ret ? ret : count;
}
@@ -212,8 +208,6 @@ del_port_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct nsim_bus_dev *nsim_bus_dev = to_nsim_bus_dev(dev);
- struct nsim_dev *nsim_dev = dev_get_drvdata(dev);
- struct devlink *devlink;
unsigned int port_index;
int ret;

@@ -224,12 +218,10 @@ del_port_store(struct device *dev, struct device_attribute *attr,
if (ret)
return ret;

- devlink = priv_to_devlink(nsim_dev);
+ if (!mutex_trylock(&nsim_bus_dev->nsim_bus_reload_lock))
+ return -EBUSY;

- mutex_lock(&nsim_bus_dev->nsim_bus_reload_lock);
- devlink_reload_disable(devlink);
ret = nsim_dev_port_del(nsim_bus_dev, NSIM_DEV_PORT_TYPE_PF, port_index);
- devlink_reload_enable(devlink);
mutex_unlock(&nsim_bus_dev->nsim_bus_reload_lock);
return ret ? ret : count;
}
diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index d538a39d4225..ff5714209b86 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -864,16 +864,23 @@ static int nsim_dev_reload_down(struct devlink *devlink, bool netns_change,
struct netlink_ext_ack *extack)
{
struct nsim_dev *nsim_dev = devlink_priv(devlink);
+ struct nsim_bus_dev *nsim_bus_dev;
+
+ nsim_bus_dev = nsim_dev->nsim_bus_dev;
+ if (!mutex_trylock(&nsim_bus_dev->nsim_bus_reload_lock))
+ return -EOPNOTSUPP;

if (nsim_dev->dont_allow_reload) {
/* For testing purposes, user set debugfs dont_allow_reload
* value to true. So forbid it.
*/
NL_SET_ERR_MSG_MOD(extack, "User forbid the reload for testing purposes");
+ mutex_unlock(&nsim_bus_dev->nsim_bus_reload_lock);
return -EOPNOTSUPP;
}

nsim_dev_reload_destroy(nsim_dev);
+ mutex_unlock(&nsim_bus_dev->nsim_bus_reload_lock);
return 0;
}

--
2.31.1