[PATCH net-next v2 3/4] devlink: expose get/put functions
From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-10-30 17:19:10
Subsystem:
devlink, networking [general], the rest · Maintainers:
Jiri Pirko, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Allow those who hold implicit reference on a devlink instance to try to take a full ref on it. This will be used from netdev code which has an implicit ref because of driver call ordering. Note that after recent changes devlink_unregister() may happen before netdev unregister, but devlink_free() should still happen after, so we are safe to try, but we can't just refcount_inc() and assume it's not zero. Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- include/net/devlink.h | 12 ++++++++++++ net/core/devlink.c | 8 +++++--- 2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 1b1317d378de..991ce48f77ca 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h@@ -1726,6 +1726,9 @@ devlink_trap_policers_unregister(struct devlink *devlink, #if IS_ENABLED(CONFIG_NET_DEVLINK) +struct devlink *__must_check devlink_try_get(struct devlink *devlink); +void devlink_put(struct devlink *devlink); + void devlink_compat_running_version(struct net_device *dev, char *buf, size_t len); int devlink_compat_flash_update(struct net_device *dev, const char *file_name);
@@ -1736,6 +1739,15 @@ int devlink_compat_switch_id_get(struct net_device *dev, #else +static inline struct devlink *devlink_try_get(struct devlink *devlink) +{ + return NULL; +} + +static inline void devlink_put(struct devlink *devlink) +{ +} + static inline void devlink_compat_running_version(struct net_device *dev, char *buf, size_t len) {
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 2d8abe88c673..100d87fd3f65 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c@@ -182,15 +182,17 @@ struct net *devlink_net(const struct devlink *devlink) } EXPORT_SYMBOL_GPL(devlink_net); -static void devlink_put(struct devlink *devlink) +void devlink_put(struct devlink *devlink) { if (refcount_dec_and_test(&devlink->refcount)) complete(&devlink->comp); } -static bool __must_check devlink_try_get(struct devlink *devlink) +struct devlink *__must_check devlink_try_get(struct devlink *devlink) { - return refcount_inc_not_zero(&devlink->refcount); + if (refcount_inc_not_zero(&devlink->refcount)) + return devlink; + return NULL; } static struct devlink *devlink_get_from_attrs(struct net *net,
--
2.31.1