Merge branch 'implement-dev-info-and-dev-flash-for-line-cards'

Jiri Pirko says:

====================
Implement dev info and dev flash for line cards

This patchset implements two features:
1) "devlink dev info" is exposed for line card (patches 6-9)
2) "devlink dev flash" is implemented for line card gearbox
   flashing (patch 10)

For every line card, "a nested" auxiliary device is created which
allows to bind the features mentioned above (patch 4).

The relationship between line card and its auxiliary dev devlink
is carried over extra line card netlink attribute (patches 3 and 5).

The first patch removes devlink_mutex from devlink_register/unregister()
which eliminates possible deadlock during devlink reload command. The
second patchset follows up with putting net pointer check into new
helper.

Examples:

$ devlink lc show pci/0000:01:00.0 lc 1
pci/0000:01:00.0:
  lc 1 state active type 16x100G nested_devlink auxiliary/mlxsw_core.lc.0
    supported_types:
       16x100G

$ devlink dev show auxiliary/mlxsw_core.lc.0
auxiliary/mlxsw_core.lc.0

$ devlink dev info auxiliary/mlxsw_core.lc.0
auxiliary/mlxsw_core.lc.0:
  versions:
      fixed:
        hw.revision 0
        fw.psid MT_0000000749
      running:
        ini.version 4
        fw 19.2010.1312

$ devlink dev flash auxiliary/mlxsw_core.lc.0 file mellanox/fw-AGB-rel-19_2010_1312-022-EVB.mfa2
====================

Link: https://lore.kernel.org/r/20220725082925.366455-1-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 131 insertions, 157 deletions

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 98d79feeb3dc..698b2d6e0ec7 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -70,6 +70,7 @@ struct devlink {
 	u8 reload_failed:1;
 	refcount_t refcount;
 	struct completion comp;
+	struct rcu_head rcu;
 	char priv[] __aligned(NETDEV_ALIGN);
 };
 
@@ -88,6 +89,7 @@ struct devlink_linecard {
 	const char *type;
 	struct devlink_linecard_type *types;
 	unsigned int types_count;
+	struct devlink *nested_devlink;
 };
 
 /**
@@ -221,8 +223,6 @@ static DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
 /* devlink_mutex
  *
  * An overall lock guarding every operation coming from userspace.
- * It also guards devlink devices list and it is taken when
- * driver registers/unregisters it.
  */
 static DEFINE_MUTEX(devlink_mutex);
 
@@ -232,10 +232,21 @@ struct net *devlink_net(const struct devlink *devlink)
 }
 EXPORT_SYMBOL_GPL(devlink_net);
 
+static void __devlink_put_rcu(struct rcu_head *head)
+{
+	struct devlink *devlink = container_of(head, struct devlink, rcu);
+
+	complete(&devlink->comp);
+}
+
 void devlink_put(struct devlink *devlink)
 {
 	if (refcount_dec_and_test(&devlink->refcount))
-		complete(&devlink->comp);
+		/* Make sure unregister operation that may await the completion
+		 * is unblocked only after all users are after the end of
+		 * RCU grace period.
+		 */
+		call_rcu(&devlink->rcu, __devlink_put_rcu);
 }
 
 struct devlink *__must_check devlink_try_get(struct devlink *devlink)
@@ -278,12 +289,62 @@ void devl_unlock(struct devlink *devlink)
 }
 EXPORT_SYMBOL_GPL(devl_unlock);
 
+static struct devlink *
+devlinks_xa_find_get(struct net *net, unsigned long *indexp, xa_mark_t filter,
+		     void * (*xa_find_fn)(struct xarray *, unsigned long *,
+					  unsigned long, xa_mark_t))
+{
+	struct devlink *devlink;
+
+	rcu_read_lock();
+retry:
+	devlink = xa_find_fn(&devlinks, indexp, ULONG_MAX, DEVLINK_REGISTERED);
+	if (!devlink)
+		goto unlock;
+	/* For a possible retry, the xa_find_after() should be always used */
+	xa_find_fn = xa_find_after;
+	if (!devlink_try_get(devlink))
+		goto retry;
+	if (!net_eq(devlink_net(devlink), net)) {
+		devlink_put(devlink);
+		goto retry;
+	}
+unlock:
+	rcu_read_unlock();
+	return devlink;
+}
+
+static struct devlink *devlinks_xa_find_get_first(struct net *net,
+						  unsigned long *indexp,
+						  xa_mark_t filter)
+{
+	return devlinks_xa_find_get(net, indexp, filter, xa_find);
+}
+
+static struct devlink *devlinks_xa_find_get_next(struct net *net,
+						 unsigned long *indexp,
+						 xa_mark_t filter)
+{
+	return devlinks_xa_find_get(net, indexp, filter, xa_find_after);
+}
+
+/* Iterate over devlink pointers which were possible to get reference to.
+ * devlink_put() needs to be called for each iterated devlink pointer
+ * in loop body in order to release the reference.
+ */
+#define devlinks_xa_for_each_get(net, index, devlink, filter)			\
+	for (index = 0,								\
+	     devlink = devlinks_xa_find_get_first(net, &index, filter);		\
+	     devlink; devlink = devlinks_xa_find_get_next(net, &index, filter))
+
+#define devlinks_xa_for_each_registered_get(net, index, devlink)		\
+	devlinks_xa_for_each_get(net, index, devlink, DEVLINK_REGISTERED)
+
 static struct devlink *devlink_get_from_attrs(struct net *net,
 					      struct nlattr **attrs)
 {
 	struct devlink *devlink;
 	unsigned long index;
-	bool found = false;
 	char *busname;
 	char *devname;
 
@@ -293,21 +354,14 @@ static struct devlink *devlink_get_from_attrs(struct net *net,
 	busname = nla_data(attrs[DEVLINK_ATTR_BUS_NAME]);
 	devname = nla_data(attrs[DEVLINK_ATTR_DEV_NAME]);
 
-	lockdep_assert_held(&devlink_mutex);
-
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
+	devlinks_xa_for_each_registered_get(net, index, devlink) {
 		if (strcmp(devlink->dev->bus->name, busname) == 0 &&
-		    strcmp(dev_name(devlink->dev), devname) == 0 &&
-		    net_eq(devlink_net(devlink), net)) {
-			found = true;
-			break;
-		}
+		    strcmp(dev_name(devlink->dev), devname) == 0)
+			return devlink;
+		devlink_put(devlink);
 	}
 
-	if (!found || !devlink_try_get(devlink))
-		devlink = ERR_PTR(-ENODEV);
-
-	return devlink;
+	return ERR_PTR(-ENODEV);
 }
 
 static struct devlink_port *devlink_port_get_by_index(struct devlink *devlink,
@@ -803,6 +857,24 @@ static int devlink_nl_put_handle(struct sk_buff *msg, struct devlink *devlink)
 	return 0;
 }
 
+static int devlink_nl_put_nested_handle(struct sk_buff *msg, struct devlink *devlink)
+{
+	struct nlattr *nested_attr;
+
+	nested_attr = nla_nest_start(msg, DEVLINK_ATTR_NESTED_DEVLINK);
+	if (!nested_attr)
+		return -EMSGSIZE;
+	if (devlink_nl_put_handle(msg, devlink))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, nested_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, nested_attr);
+	return -EMSGSIZE;
+}
+
 struct devlink_reload_combination {
 	enum devlink_reload_action action;
 	enum devlink_reload_limit limit;
@@ -1329,13 +1401,7 @@ static int devlink_nl_cmd_rate_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(devlink_rate, &devlink->rate_list, list) {
 			enum devlink_command cmd = DEVLINK_CMD_RATE_NEW;
@@ -1356,7 +1422,6 @@ static int devlink_nl_cmd_rate_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -1432,15 +1497,7 @@ static int devlink_nl_cmd_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk))) {
-			devlink_put(devlink);
-			continue;
-		}
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		if (idx < start) {
 			idx++;
 			devlink_put(devlink);
@@ -1495,13 +1552,7 @@ static int devlink_nl_cmd_port_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(devlink_port, &devlink->port_list, list) {
 			if (idx < start) {
@@ -1521,7 +1572,6 @@ static int devlink_nl_cmd_port_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -2104,6 +2154,10 @@ static int devlink_nl_linecard_fill(struct sk_buff *msg,
 		nla_nest_end(msg, attr);
 	}
 
+	if (linecard->nested_devlink &&
+	    devlink_nl_put_nested_handle(msg, linecard->nested_devlink))
+		goto nla_put_failure;
+
 	genlmsg_end(msg, hdr);
 	return 0;
 
@@ -2177,13 +2231,7 @@ static int devlink_nl_cmd_linecard_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		mutex_lock(&devlink->linecards_lock);
 		list_for_each_entry(linecard, &devlink->linecard_list, list) {
 			if (idx < start) {
@@ -2206,7 +2254,6 @@ static int devlink_nl_cmd_linecard_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		mutex_unlock(&devlink->linecards_lock);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -2449,13 +2496,7 @@ static int devlink_nl_cmd_sb_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(devlink_sb, &devlink->sb_list, list) {
 			if (idx < start) {
@@ -2475,7 +2516,6 @@ static int devlink_nl_cmd_sb_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -2601,10 +2641,7 @@ static int devlink_nl_cmd_sb_pool_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)) ||
 		    !devlink->ops->sb_pool_get)
 			goto retry;
@@ -2822,12 +2859,8 @@ static int devlink_nl_cmd_sb_port_pool_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)) ||
-		    !devlink->ops->sb_port_pool_get)
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
+		if (!devlink->ops->sb_port_pool_get)
 			goto retry;
 
 		devl_lock(devlink);
@@ -3071,12 +3104,8 @@ devlink_nl_cmd_sb_tc_pool_bind_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)) ||
-		    !devlink->ops->sb_tc_pool_bind_get)
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
+		if (!devlink->ops->sb_tc_pool_bind_get)
 			goto retry;
 
 		devl_lock(devlink);
@@ -5158,13 +5187,7 @@ static int devlink_nl_cmd_param_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(param_item, &devlink->param_list, list) {
 			if (idx < start) {
@@ -5186,7 +5209,6 @@ static int devlink_nl_cmd_param_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -5393,13 +5415,7 @@ static int devlink_nl_cmd_port_param_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(devlink_port, &devlink->port_list, list) {
 			list_for_each_entry(param_item,
@@ -5426,7 +5442,6 @@ static int devlink_nl_cmd_port_param_get_dumpit(struct sk_buff *msg,
 			}
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -5977,16 +5992,9 @@ static int devlink_nl_cmd_region_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		err = devlink_nl_cmd_region_get_devlink_dumpit(msg, cb, devlink,
 							       &idx, start);
-retry:
 		devlink_put(devlink);
 		if (err)
 			goto out;
@@ -6511,13 +6519,7 @@ static int devlink_nl_cmd_info_get_dumpit(struct sk_buff *msg,
 	int err = 0;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		if (idx < start || !devlink->ops->info_get)
 			goto inc;
 
@@ -6535,7 +6537,6 @@ static int devlink_nl_cmd_info_get_dumpit(struct sk_buff *msg,
 		}
 inc:
 		idx++;
-retry:
 		devlink_put(devlink);
 	}
 	mutex_unlock(&devlink_mutex);
@@ -7691,13 +7692,7 @@ devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry_rep;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		mutex_lock(&devlink->reporters_lock);
 		list_for_each_entry(reporter, &devlink->reporter_list,
 				    list) {
@@ -7717,17 +7712,10 @@ devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		mutex_unlock(&devlink->reporters_lock);
-retry_rep:
 		devlink_put(devlink);
 	}
 
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry_port;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(port, &devlink->port_list, list) {
 			mutex_lock(&port->reporters_lock);
@@ -7752,7 +7740,6 @@ retry_rep:
 			mutex_unlock(&port->reporters_lock);
 		}
 		devl_unlock(devlink);
-retry_port:
 		devlink_put(devlink);
 	}
 out:
@@ -8291,13 +8278,7 @@ static int devlink_nl_cmd_trap_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(trap_item, &devlink->trap_list, list) {
 			if (idx < start) {
@@ -8317,7 +8298,6 @@ static int devlink_nl_cmd_trap_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -8518,13 +8498,7 @@ static int devlink_nl_cmd_trap_group_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(group_item, &devlink->trap_group_list,
 				    list) {
@@ -8545,7 +8519,6 @@ static int devlink_nl_cmd_trap_group_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -8832,13 +8805,7 @@ static int devlink_nl_cmd_trap_policer_get_dumpit(struct sk_buff *msg,
 	int err;
 
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
 		devl_lock(devlink);
 		list_for_each_entry(policer_item, &devlink->trap_policer_list,
 				    list) {
@@ -8859,7 +8826,6 @@ static int devlink_nl_cmd_trap_policer_get_dumpit(struct sk_buff *msg,
 			idx++;
 		}
 		devl_unlock(devlink);
-retry:
 		devlink_put(devlink);
 	}
 out:
@@ -9589,10 +9555,8 @@ void devlink_register(struct devlink *devlink)
 	ASSERT_DEVLINK_NOT_REGISTERED(devlink);
 	/* Make sure that we are in .probe() routine */
 
-	mutex_lock(&devlink_mutex);
 	xa_set_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
 	devlink_notify_register(devlink);
-	mutex_unlock(&devlink_mutex);
 }
 EXPORT_SYMBOL_GPL(devlink_register);
 
@@ -9609,10 +9573,8 @@ void devlink_unregister(struct devlink *devlink)
 	devlink_put(devlink);
 	wait_for_completion(&devlink->comp);
 
-	mutex_lock(&devlink_mutex);
 	devlink_notify_unregister(devlink);
 	xa_clear_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
-	mutex_unlock(&devlink_mutex);
 }
 EXPORT_SYMBOL_GPL(devlink_unregister);
 
@@ -10316,6 +10278,7 @@ EXPORT_SYMBOL_GPL(devlink_linecard_provision_set);
 void devlink_linecard_provision_clear(struct devlink_linecard *linecard)
 {
 	mutex_lock(&linecard->state_lock);
+	WARN_ON(linecard->nested_devlink);
 	linecard->state = DEVLINK_LINECARD_STATE_UNPROVISIONED;
 	linecard->type = NULL;
 	devlink_linecard_notify(linecard, DEVLINK_CMD_LINECARD_NEW);
@@ -10334,6 +10297,7 @@ EXPORT_SYMBOL_GPL(devlink_linecard_provision_clear);
 void devlink_linecard_provision_fail(struct devlink_linecard *linecard)
 {
 	mutex_lock(&linecard->state_lock);
+	WARN_ON(linecard->nested_devlink);
 	linecard->state = DEVLINK_LINECARD_STATE_PROVISIONING_FAILED;
 	devlink_linecard_notify(linecard, DEVLINK_CMD_LINECARD_NEW);
 	mutex_unlock(&linecard->state_lock);
@@ -10381,6 +10345,23 @@ void devlink_linecard_deactivate(struct devlink_linecard *linecard)
 }
 EXPORT_SYMBOL_GPL(devlink_linecard_deactivate);
 
+/**
+ *	devlink_linecard_nested_dl_set - Attach/detach nested devlink
+ *					 instance to linecard.
+ *
+ *	@linecard: devlink linecard
+ *	@nested_devlink: devlink instance to attach or NULL to detach
+ */
+void devlink_linecard_nested_dl_set(struct devlink_linecard *linecard,
+				    struct devlink *nested_devlink)
+{
+	mutex_lock(&linecard->state_lock);
+	linecard->nested_devlink = nested_devlink;
+	devlink_linecard_notify(linecard, DEVLINK_CMD_LINECARD_NEW);
+	mutex_unlock(&linecard->state_lock);
+}
+EXPORT_SYMBOL_GPL(devlink_linecard_nested_dl_set);
+
 int devl_sb_register(struct devlink *devlink, unsigned int sb_index,
 		     u32 size, u16 ingress_pools_count,
 		     u16 egress_pools_count, u16 ingress_tc_count,
@@ -12281,13 +12262,7 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
 	 * all devlink instances from this namespace into init_net.
 	 */
 	mutex_lock(&devlink_mutex);
-	xa_for_each_marked(&devlinks, index, devlink, DEVLINK_REGISTERED) {
-		if (!devlink_try_get(devlink))
-			continue;
-
-		if (!net_eq(devlink_net(devlink), net))
-			goto retry;
-
+	devlinks_xa_for_each_registered_get(net, index, devlink) {
 		WARN_ON(!(devlink->features & DEVLINK_F_RELOAD));
 		err = devlink_reload(devlink, &init_net,
 				     DEVLINK_RELOAD_ACTION_DRIVER_REINIT,
@@ -12295,7 +12270,6 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
 				     &actions_performed, NULL);
 		if (err && err != -EOPNOTSUPP)
 			pr_warn("Failed to reload devlink instance into init_net\n");
-retry:
 		devlink_put(devlink);
 	}
 	mutex_unlock(&devlink_mutex);