devlink: create a special NDO for getting the devlink instance

Instead of iterating over all devlink ports add a NDO which
will return the devlink instance from the driver.

v2: add the netdev_to_devlink() helper (Michal)
v3: check that devlink has ops (Florian)
v4: hold devlink_mutex (Jiri)

Suggested-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -941,6 +941,8 @@ struct dev_ifalias {
 	char ifalias[];
 };
 
+struct devlink;
+
 /*
  * This structure defines the management hooks for network devices.
  * The following hooks can be defined; unless noted otherwise, they are
@@ -1249,6 +1251,10 @@ struct dev_ifalias {
  *	that got dropped are freed/returned via xdp_return_frame().
  *	Returns negative number, means general error invoking ndo, meaning
  *	no frames were xmit'ed and core-caller will free all frames.
+ * struct devlink *(*ndo_get_devlink)(struct net_device *dev);
+ *	Get devlink instance associated with a given netdev.
+ *	Called with a reference on the netdevice and devlink locks only,
+ *	rtnl_lock is not held.
  */
 struct net_device_ops {
 	int			(*ndo_init)(struct net_device *dev);
@@ -1447,6 +1453,7 @@ struct net_device_ops {
 						u32 flags);
 	int			(*ndo_xsk_async_xmit)(struct net_device *dev,
 						      u32 queue_id);
+	struct devlink *	(*ndo_get_devlink)(struct net_device *dev);
 };
 
 /**

include/net/devlink.h

@@ -538,6 +538,15 @@ static inline struct devlink *priv_to_devlink(void *priv)
 	return container_of(priv, struct devlink, priv);
 }
 
+static inline struct devlink *netdev_to_devlink(struct net_device *dev)
+{
+#if IS_ENABLED(CONFIG_NET_DEVLINK)
+	if (dev->netdev_ops->ndo_get_devlink)
+		return dev->netdev_ops->ndo_get_devlink(dev);
+#endif
+	return NULL;
+}
+
 struct ib_device;
 
 #if IS_ENABLED(CONFIG_NET_DEVLINK)

net/core/devlink.c

@@ -6397,9 +6397,6 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 	struct sk_buff *msg;
 	int rem, err;
 
-	if (!devlink->ops->info_get)
-		return;
-
 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!msg)
 		return;
@@ -6431,55 +6428,36 @@ free_msg:
 void devlink_compat_running_version(struct net_device *dev,
 				    char *buf, size_t len)
 {
-	struct devlink_port *devlink_port;
 	struct devlink *devlink;
 
 	mutex_lock(&devlink_mutex);
-	list_for_each_entry(devlink, &devlink_list, list) {
-		mutex_lock(&devlink->lock);
-		list_for_each_entry(devlink_port, &devlink->port_list, list) {
-			if (devlink_port->type == DEVLINK_PORT_TYPE_ETH &&
-			    devlink_port->type_dev == dev) {
-				__devlink_compat_running_version(devlink,
-								 buf, len);
-				mutex_unlock(&devlink->lock);
-				goto out;
-			}
-		}
-		mutex_unlock(&devlink->lock);
-	}
-out:
+	devlink = netdev_to_devlink(dev);
+	if (!devlink || !devlink->ops || !devlink->ops->info_get)
+		goto unlock_list;
+
+	mutex_lock(&devlink->lock);
+	__devlink_compat_running_version(devlink, buf, len);
+	mutex_unlock(&devlink->lock);
+unlock_list:
 	mutex_unlock(&devlink_mutex);
 }
 
 int devlink_compat_flash_update(struct net_device *dev, const char *file_name)
 {
-	struct devlink_port *devlink_port;
 	struct devlink *devlink;
+	int ret = -EOPNOTSUPP;
 
 	mutex_lock(&devlink_mutex);
-	list_for_each_entry(devlink, &devlink_list, list) {
-		mutex_lock(&devlink->lock);
-		list_for_each_entry(devlink_port, &devlink->port_list, list) {
-			int ret = -EOPNOTSUPP;
+	devlink = netdev_to_devlink(dev);
+	if (!devlink || !devlink->ops || !devlink->ops->flash_update)
+		goto unlock_list;
 
-			if (devlink_port->type != DEVLINK_PORT_TYPE_ETH ||
-			    devlink_port->type_dev != dev)
-				continue;
-
-			mutex_unlock(&devlink_mutex);
-			if (devlink->ops->flash_update)
-				ret = devlink->ops->flash_update(devlink,
-								 file_name,
-								 NULL, NULL);
-			mutex_unlock(&devlink->lock);
-			return ret;
-		}
-		mutex_unlock(&devlink->lock);
-	}
+	mutex_lock(&devlink->lock);
+	ret = devlink->ops->flash_update(devlink, file_name, NULL, NULL);
+	mutex_unlock(&devlink->lock);
+unlock_list:
 	mutex_unlock(&devlink_mutex);
-
-	return -EOPNOTSUPP;
+	return ret;
 }
 
 static int __init devlink_init(void)