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MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, 24 Feb 2019 12:00:03 +0100, Jiri Pirko wrote: > Fri, Feb 22, 2019 at 11:07:56PM CET, jakub.kicinski@netronome.com wrote: > >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 > >--- > > 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 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: 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); ?