[PATCH net-next V6 4/4] devlink: Apply eswitch mode boot defaults

[Mark Bloch <mbloch@nvidia.com>]

Apply parsed devlink_eswitch_mode= defaults after devlink registration
and after successful reload.

Mark the default mode as pending when a devlink instance is allocated.
Before devl_unlock() releases the instance lock, apply a pending default
when the instance is registered.

Clear the pending state before calling into the driver so the boot
default remains a one-shot operation even if the mode change fails.

For successful reloads that performed DRIVER_REINIT, devlink_reload()
already holds the devlink instance lock and the driver has completed
reload_up(). Clear the pending state and apply the default directly from
the reload path.

Treat an explicit user eswitch mode request as consuming the pending
default mode.

Signed-off-by: Mark Bloch <mbloch@nvidia.com>
---
 net/devlink/core.c          |  3 ++
 net/devlink/default.c       | 70 +++++++++++++++++++++++++++++++++++--
 net/devlink/dev.c           |  6 ++++
 net/devlink/devl_internal.h |  5 +++
 4 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/net/devlink/core.c b/net/devlink/core.c
index fc14ee5d9dcf..cea4afc27dd9 100644
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -317,6 +317,7 @@ EXPORT_SYMBOL_GPL(devl_trylock);
 
 void devl_unlock(struct devlink *devlink)
 {
+	devlink_default_esw_mode_apply_pending(devlink);
 	mutex_unlock(&devlink->lock);
 }
 EXPORT_SYMBOL_GPL(devl_unlock);
@@ -429,6 +430,7 @@ void devl_unregister(struct devlink *devlink)
 	ASSERT_DEVLINK_REGISTERED(devlink);
 	devl_assert_locked(devlink);
 
+	devlink_default_esw_mode_apply_pending_clear(devlink);
 	devlink_notify_unregister(devlink);
 	xa_clear_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
 	devlink_rel_put(devlink);
@@ -490,6 +492,7 @@ struct devlink *__devlink_alloc(const struct devlink_ops *ops, size_t priv_size,
 	INIT_LIST_HEAD(&devlink->trap_group_list);
 	INIT_LIST_HEAD(&devlink->trap_policer_list);
 	INIT_RCU_WORK(&devlink->rwork, devlink_release);
+	devlink_default_esw_mode_instance_init(devlink);
 	lockdep_register_key(&devlink->lock_key);
 	mutex_init(&devlink->lock);
 	lockdep_set_class(&devlink->lock, &devlink->lock_key);
diff --git a/net/devlink/default.c b/net/devlink/default.c
index 8434af83ea69..77cc356dfac9 100644
--- a/net/devlink/default.c
+++ b/net/devlink/default.c
@@ -10,6 +10,7 @@
 
 static char *devlink_default_esw_mode_param;
 static bool devlink_default_esw_mode_match_all;
+static bool devlink_default_esw_mode_enabled;
 static enum devlink_eswitch_mode devlink_default_esw_mode;
 static LIST_HEAD(devlink_default_esw_mode_nodes);
 
@@ -154,6 +155,7 @@ static void __init devlink_default_esw_mode_nodes_clear(void)
 	}
 
 	devlink_default_esw_mode_match_all = false;
+	devlink_default_esw_mode_enabled = false;
 }
 
 static int __init devlink_default_esw_mode_parse(char *str)
@@ -180,14 +182,78 @@ static int __init devlink_default_esw_mode_parse(char *str)
 		return err;
 
 	err = devlink_default_esw_mode_handles_parse(handles);
-	if (err)
+	if (err) {
 		devlink_default_esw_mode_nodes_clear();
-	else
+	} else {
 		devlink_default_esw_mode = esw_mode;
+		devlink_default_esw_mode_enabled = true;
+	}
 
 	return err;
 }
 
+static bool devlink_default_esw_mode_match(struct devlink *devlink)
+{
+	const char *bus_name = devlink_bus_name(devlink);
+	const char *dev_name = devlink_dev_name(devlink);
+	struct devlink_default_esw_mode_node *node;
+
+	if (devlink_default_esw_mode_match_all)
+		return true;
+
+	node = devlink_default_esw_mode_node_find(bus_name, dev_name);
+	return !!node;
+}
+
+void devlink_default_esw_mode_apply_locked(struct devlink *devlink)
+{
+	const struct devlink_ops *ops = devlink->ops;
+	int err;
+
+	devl_assert_locked(devlink);
+
+	if (!devlink_default_esw_mode_match(devlink))
+		return;
+
+	if (!ops->eswitch_mode_set) {
+		if (!devlink_default_esw_mode_match_all)
+			devl_warn(devlink,
+				  "devlink_eswitch_mode= selected this device but eswitch mode setting is not supported\n");
+		return;
+	}
+
+	err = devlink_eswitch_mode_set(devlink, devlink_default_esw_mode, NULL);
+	if (err)
+		devl_warn(devlink,
+			  "Couldn't apply default eswitch mode, err %d\n",
+			  err);
+}
+
+void devlink_default_esw_mode_apply_pending(struct devlink *devlink)
+{
+	devl_assert_locked(devlink);
+
+	if (!devlink->default_esw_mode_apply_pending ||
+	    !__devl_is_registered(devlink))
+		return;
+
+	devlink->default_esw_mode_apply_pending = false;
+	devlink_default_esw_mode_apply_locked(devlink);
+}
+
+void devlink_default_esw_mode_instance_init(struct devlink *devlink)
+{
+	devlink->default_esw_mode_apply_pending =
+		devlink_default_esw_mode_enabled;
+}
+
+void devlink_default_esw_mode_apply_pending_clear(struct devlink *devlink)
+{
+	devl_assert_locked(devlink);
+
+	devlink->default_esw_mode_apply_pending = false;
+}
+
 static int __init devlink_default_esw_mode_setup(char *str)
 {
 	devlink_default_esw_mode_param = str;
diff --git a/net/devlink/dev.c b/net/devlink/dev.c
index 119ef105d0a7..611bb6bfd492 100644
--- a/net/devlink/dev.c
+++ b/net/devlink/dev.c
@@ -478,6 +478,11 @@ int devlink_reload(struct devlink *devlink, struct net *dest_net,
 		return err;
 
 	WARN_ON(!(*actions_performed & BIT(action)));
+	if (*actions_performed & BIT(DEVLINK_RELOAD_ACTION_DRIVER_REINIT)) {
+		devlink_default_esw_mode_apply_pending_clear(devlink);
+		devlink_default_esw_mode_apply_locked(devlink);
+	}
+
 	/* Catch driver on updating the remote action within devlink reload */
 	WARN_ON(memcmp(remote_reload_stats, devlink->stats.remote_reload_stats,
 		       sizeof(remote_reload_stats)));
@@ -731,6 +736,7 @@ int devlink_nl_eswitch_set_doit(struct sk_buff *skb, struct genl_info *info)
 	u16 mode;
 
 	if (info->attrs[DEVLINK_ATTR_ESWITCH_MODE]) {
+		devlink_default_esw_mode_apply_pending_clear(devlink);
 		mode = nla_get_u16(info->attrs[DEVLINK_ATTR_ESWITCH_MODE]);
 		err = devlink_eswitch_mode_set(devlink, mode, info->extack);
 		if (err)
diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h
index fe9ad58515d4..97f53394b1c0 100644
--- a/net/devlink/devl_internal.h
+++ b/net/devlink/devl_internal.h
@@ -58,6 +58,7 @@ struct devlink {
 	struct mutex lock;
 	struct lock_class_key lock_key;
 	u8 reload_failed:1;
+	u8 default_esw_mode_apply_pending:1;
 	refcount_t refcount;
 	struct rcu_work rwork;
 	struct devlink_rel *rel;
@@ -73,6 +74,10 @@ struct devlink *__devlink_alloc(const struct devlink_ops *ops, size_t priv_size,
 				const struct device_driver *dev_driver);
 int devlink_default_esw_mode_init(void);
 void devlink_default_esw_mode_cleanup(void);
+void devlink_default_esw_mode_instance_init(struct devlink *devlink);
+void devlink_default_esw_mode_apply_locked(struct devlink *devlink);
+void devlink_default_esw_mode_apply_pending(struct devlink *devlink);
+void devlink_default_esw_mode_apply_pending_clear(struct devlink *devlink);
 
 #define devl_warn(devlink, format, args...)				\
 	do {								\
-- 
2.43.0