[PATCH net-next 7/7] ethtool: add compat for devlink info

[Jakub Kicinski <jakub.kicinski@netronome.com>]

If driver did not fill the fw_version field, try to call into
the new devlink get_info op and collect the versions that way.
We assume ethtool was always reporting running versions.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 include/net/devlink.h |  7 ++++++
 net/core/devlink.c    | 52 ++++++++++++++++++++++++++++++++++++++++++-
 net/core/ethtool.c    |  7 ++++++
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 14da3632e8fc..b047360b88a9 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -616,6 +616,8 @@ int devlink_info_report_version(struct devlink_info_req *req,
 				enum devlink_version_type type,
 				const char *version_name,
 				const char *version_value);
+void devlink_compat_running_versions(struct net_device *dev,
+				     char *buf, size_t len);
 
 #else
 
@@ -896,6 +898,11 @@ devlink_info_report_version(struct devlink_info_req *req,
 {
 	return 0;
 }
+
+static inline void
+devlink_compat_running_versions(struct net_device *dev, char *buf, size_t len)
+{
+}
 #endif
 
 #endif /* _NET_DEVLINK_H_ */
diff --git a/net/core/devlink.c b/net/core/devlink.c
index f0c5f9bd96b7..99037bf15fb8 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -3598,12 +3598,18 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 }
 
 struct devlink_info_req {
+	bool compat;
 	struct sk_buff *msg;
+	/* For compat call */
+	char *buf;
+	size_t len;
 };
 
 int devlink_info_report_driver_name(struct devlink_info_req *req,
 				    const char *name)
 {
+	if (req->compat)
+		return 0;
 	return nla_put_string(req->msg, DEVLINK_ATTR_INFO_DRV_NAME, name);
 }
 EXPORT_SYMBOL_GPL(devlink_info_report_driver_name);
@@ -3611,6 +3617,8 @@ EXPORT_SYMBOL_GPL(devlink_info_report_driver_name);
 int devlink_info_report_serial_number(struct devlink_info_req *req,
 				      const char *sn)
 {
+	if (req->compat)
+		return 0;
 	return nla_put_string(req->msg, DEVLINK_ATTR_INFO_SERIAL_NUMBER, sn);
 }
 EXPORT_SYMBOL_GPL(devlink_info_report_serial_number);
@@ -3626,7 +3634,15 @@ int devlink_info_report_version(struct devlink_info_req *req,
 		[DEVLINK_VERSION_RUNNING] = DEVLINK_ATTR_INFO_VERSION_RUNNING,
 	};
 	struct nlattr *nest;
-	int err;
+	int len, err;
+
+	if (req->compat) {
+		if (type == DEVLINK_VERSION_RUNNING) {
+			len = strlcpy(req->buf, version_value, req->len);
+			req->len = max_t(size_t, 0, req->len - len);
+		}
+		return 0;
+	}
 
 	if (type >= ARRAY_SIZE(type2attr) || !type2attr[type])
 		return -EINVAL;
@@ -3672,6 +3688,7 @@ devlink_nl_info_fill(struct sk_buff *msg, struct devlink *devlink,
 	if (devlink_nl_put_handle(msg, devlink))
 		goto err_cancel_msg;
 
+	memset(&req, 0, sizeof(req));
 	req.msg = msg;
 	err = devlink->ops->info_get(devlink, &req, extack);
 	if (err)
@@ -4962,6 +4979,39 @@ int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
 }
 EXPORT_SYMBOL_GPL(devlink_region_snapshot_create);
 
+void devlink_compat_running_versions(struct net_device *dev,
+				     char *buf, size_t len)
+{
+	struct devlink_port *devlink_port;
+	struct devlink_info_req req;
+	struct devlink *devlink;
+	bool found = false;
+
+	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) {
+				mutex_unlock(&devlink->lock);
+				found = true;
+				goto out;
+			}
+		}
+		mutex_unlock(&devlink->lock);
+	}
+out:
+	if (found && devlink->ops->info_get) {
+		memset(&req, 0, sizeof(req));
+		req.compat = true;
+		req.buf = buf;
+		req.len = len;
+
+		devlink->ops->info_get(devlink, &req, NULL);
+	}
+	mutex_unlock(&devlink_mutex);
+}
+
 static int __init devlink_module_init(void)
 {
 	return genl_register_family(&devlink_nl_family);
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 158264f7cfaf..176b17d11f08 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -27,6 +27,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/sched/signal.h>
 #include <linux/net.h>
+#include <net/devlink.h>
 #include <net/xdp_sock.h>
 
 /*
@@ -803,6 +804,12 @@ static noinline_for_stack int ethtool_get_drvinfo(struct net_device *dev,
 	if (ops->get_eeprom_len)
 		info.eedump_len = ops->get_eeprom_len(dev);
 
+	rtnl_unlock();
+	if (!info.fw_version[0])
+		devlink_compat_running_versions(dev, info.fw_version,
+						ARRAY_SIZE(info.fw_version));
+	rtnl_lock();
+
 	if (copy_to_user(useraddr, &info, sizeof(info)))
 		return -EFAULT;
 	return 0;
-- 
2.19.2