[PATCH net-next v2 2/5] devlink: Annotate devlink API calls

Leon Romanovsky
2021-10-03T18:12:36Z

From: Leon Romanovsky <leonro@nvidia.com>

Initial annotation patch to separate calls that needs to be executed
before or after devlink_register().

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
net/core/devlink.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 9642429cec65..4e484afeadea 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -154,6 +154,22 @@ static const struct nla_policy devlink_function_nl_policy[DEVLINK_PORT_FUNCTION_
static DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
#define DEVLINK_REGISTERED XA_MARK_1

+/* devlink instances are open to the access from the user space after
+ * devlink_register() call. Such logical barrier allows us to have certain
+ * expectations related to locking.
+ *
+ * Before *_register() - we are in initialization stage and no parallel
+ * access possible to the devlink instance. All drivers perform that phase
+ * by implicitly holding device_lock.
+ *
+ * After *_register() - users and driver can access devlink instance at
+ * the same time.
+ */
+#define ASSERT_DEVLINK_REGISTERED(d) \
+ WARN_ON_ONCE(!xa_get_mark(&devlinks, (d)->index, DEVLINK_REGISTERED))
+#define ASSERT_DEVLINK_NOT_REGISTERED(d) \
+ WARN_ON_ONCE(xa_get_mark(&devlinks, (d)->index, DEVLINK_REGISTERED))
+
/* devlink_mutex
*
* An overall lock guarding every operation coming from userspace.
@@ -9115,6 +9131,10 @@ static void devlink_notify_unregister(struct devlink *devlink)
*/
void devlink_register(struct devlink *devlink)
{
+ ASSERT_DEVLINK_NOT_REGISTERED(devlink);
+ /* Make sure that we are in .probe() routine */
+ device_lock_assert(devlink->dev);
+
mutex_lock(&devlink_mutex);
xa_set_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
devlink_notify_register(devlink);
@@ -9129,6 +9149,10 @@ EXPORT_SYMBOL_GPL(devlink_register);
*/
void devlink_unregister(struct devlink *devlink)
{
+ ASSERT_DEVLINK_REGISTERED(devlink);
+ /* Make sure that we are in .remove() routine */
+ device_lock_assert(devlink->dev);
+
devlink_put(devlink);
wait_for_completion(&devlink->comp);

@@ -9183,6 +9207,8 @@ EXPORT_SYMBOL_GPL(devlink_reload_disable);
*/
void devlink_free(struct devlink *devlink)
{
+ ASSERT_DEVLINK_NOT_REGISTERED(devlink);
+
mutex_destroy(&devlink->reporters_lock);
mutex_destroy(&devlink->lock);
WARN_ON(!list_empty(&devlink->trap_policer_list));
--
2.31.1