devlink: always check if the devlink instance is registered

Always check under the instance lock whether the devlink instance
is still / already registered.

This is a no-op for the most part, as the unregistration path currently
waits for all references. On the init path, however, we may temporarily
open up a race with netdev code, if netdevs are registered before the
devlink instance. This is temporary, the next change fixes it, and this
commit has been split out for the ease of review.

Note that in case of iterating over sub-objects which have their
own lock (regions and line cards) we assume an implicit dependency
between those objects existing and devlink unregistration.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 6 deletions

diff --git a/net/devlink/leftover.c b/net/devlink/leftover.c
index bec408da4dbe..491f821c8b77 100644
--- a/net/devlink/leftover.c
+++ b/net/devlink/leftover.c
@@ -2130,6 +2130,9 @@ static int devlink_nl_cmd_linecard_get_dumpit(struct sk_buff *msg,
 		int idx = 0;
 
 		mutex_lock(&devlink->linecards_lock);
+		if (!devl_is_registered(devlink))
+			goto next_devlink;
+
 		list_for_each_entry(linecard, &devlink->linecard_list, list) {
 			if (idx < state->idx) {
 				idx++;
@@ -2151,6 +2154,7 @@ static int devlink_nl_cmd_linecard_get_dumpit(struct sk_buff *msg,
 			}
 			idx++;
 		}
+next_devlink:
 		mutex_unlock(&devlink->linecards_lock);
 		devlink_put(devlink);
 	}
@@ -7809,6 +7813,12 @@ devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
 		int idx = 0;
 
 		mutex_lock(&devlink->reporters_lock);
+		if (!devl_is_registered(devlink)) {
+			mutex_unlock(&devlink->reporters_lock);
+			devlink_put(devlink);
+			continue;
+		}
+
 		list_for_each_entry(reporter, &devlink->reporter_list,
 				    list) {
 			if (idx < state->idx) {
@@ -7830,6 +7840,9 @@ devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
 		mutex_unlock(&devlink->reporters_lock);
 
 		devl_lock(devlink);
+		if (!devl_is_registered(devlink))
+			goto next_devlink;
+
 		xa_for_each(&devlink->ports, port_index, port) {
 			mutex_lock(&port->reporters_lock);
 			list_for_each_entry(reporter, &port->reporter_list, list) {
@@ -7853,6 +7866,7 @@ devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
 			}
 			mutex_unlock(&port->reporters_lock);
 		}
+next_devlink:
 		devl_unlock(devlink);
 		devlink_put(devlink);
 	}
@@ -12218,7 +12232,8 @@ void devlink_compat_running_version(struct devlink *devlink,
 		return;
 
 	devl_lock(devlink);
-	__devlink_compat_running_version(devlink, buf, len);
+	if (devl_is_registered(devlink))
+		__devlink_compat_running_version(devlink, buf, len);
 	devl_unlock(devlink);
 }
 
@@ -12227,20 +12242,28 @@ int devlink_compat_flash_update(struct devlink *devlink, const char *file_name)
 	struct devlink_flash_update_params params = {};
 	int ret;
 
-	if (!devlink->ops->flash_update)
-		return -EOPNOTSUPP;
+	devl_lock(devlink);
+	if (!devl_is_registered(devlink)) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	if (!devlink->ops->flash_update) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
 
 	ret = request_firmware(&params.fw, file_name, devlink->dev);
 	if (ret)
-		return ret;
+		goto out_unlock;
 
-	devl_lock(devlink);
 	devlink_flash_update_begin_notify(devlink);
 	ret = devlink->ops->flash_update(devlink, &params, NULL);
 	devlink_flash_update_end_notify(devlink);
-	devl_unlock(devlink);
 
 	release_firmware(params.fw);
+out_unlock:
+	devl_unlock(devlink);
 
 	return ret;
 }