Re: [PATCH net-next v3 5/6] devlink: hold a reference to the netdevice around ethtool compat
From: Jiri Pirko <jiri@resnulli.us>
Date: 2019-02-26 07:00:20
Mon, Feb 25, 2019 at 07:31:27PM CET, jakub.kicinski@netronome.com wrote:
On Sun, 24 Feb 2019 12:00:03 +0100, Jiri Pirko wrote:quoted
Fri, Feb 22, 2019 at 11:07:56PM CET, jakub.kicinski@netronome.com wrote:quoted
When ethtool is calling into devlink compat code make sure we have a reference on the netdevice on which the operation was invoked. v3: move the hold/lock logic into devlink_compat_* functions (Florian) Signed-off-by: Jakub Kicinski <redacted> --- net/core/devlink.c | 34 +++++++++++++++++++++++----------- net/core/ethtool.c | 13 ++----------- 2 files changed, 25 insertions(+), 22 deletions(-)diff --git a/net/core/devlink.c b/net/core/devlink.c index a13055160be0..78c6ea1870ca 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c@@ -6430,27 +6430,39 @@ void devlink_compat_running_version(struct net_device *dev,{ struct devlink *devlink; + dev_hold(dev); + rtnl_unlock();Ha, I got it now. You rely on dev_hold to make sure the devlink instance does not dissappear. But until this patch, that is not guaranteed (or I'm missing it).Yup, I think the expectation that drivers should free netdevs before unregistering devlink holds today. But it may be a source of bugs :S
Sure.
I can add take devlink_mutex, and check the devlink instance is registered. Do you prefer an explicit ->registered field like port has, or can I do this:
Yeah, let's add WARN_ON.
quoted hunk ↗ jump to hunk
diff --git a/net/core/devlink.c b/net/core/devlink.c index cefcc0f45d44..be39ad6a4e2e 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c@@ -5275,6 +5275,7 @@ struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size) return NULL; devlink->ops = ops; devlink_net_set(devlink, &init_net); + INIT_LIST_HEAD(&devlink->list); INIT_LIST_HEAD(&devlink->port_list); INIT_LIST_HEAD(&devlink->sb_list); INIT_LIST_HEAD_RCU(&devlink->dpipe_table_list);@@ -5303,6 +5304,11 @@ int devlink_register(struct devlink *devlink, struct device *dev)} EXPORT_SYMBOL_GPL(devlink_register); +static bool devlink_is_registered(struct devlink *devlink) +{ + return list_empty(&devlink->list); +} + /** * devlink_unregister - Unregister devlink instance *@@ -5312,7 +5318,7 @@ void devlink_unregister(struct devlink *devlink){ mutex_lock(&devlink_mutex); devlink_notify(devlink, DEVLINK_CMD_DEL); - list_del(&devlink->list); + list_del_init(&devlink->list); mutex_unlock(&devlink_mutex); } EXPORT_SYMBOL_GPL(devlink_unregister); ?