Merge branch 'devlink-Preparations-for-trap-policers-support'

Ido Schimmel says:

====================
devlink: Preparations for trap policers support

This patch set prepares the code for devlink-trap policer support in a
follow-up patch set [1][2]. No functional changes intended.

Policers are going to be added as attributes of packet trap groups,
which are entities used to aggregate logically related packet traps.
This will allow users, for example, to limit all the packets that
encountered an exception during routing to 10Kpps.

However, currently, device drivers register their packet trap groups
implicitly when they register their packet traps via
devlink_traps_register(). This makes it difficult to pass additional
attributes for the groups. For example, the policer bound to the group.

Therefore, this patch set converts device drivers to explicitly register
their packet trap groups. This will later allow these drivers to
register the group with additional attributes, if any.
====================

Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 202 insertions, 115 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c
index 9c300d625e04..727f6ef243df 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c
@@ -132,23 +132,23 @@ static void mlxsw_sp_rx_exception_listener(struct sk_buff *skb, u8 local_port,
 
 #define MLXSW_SP_TRAP_DROP(_id, _group_id)				      \
 	DEVLINK_TRAP_GENERIC(DROP, DROP, _id,				      \
-			     DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			     MLXSW_SP_TRAP_METADATA)
 
 #define MLXSW_SP_TRAP_DROP_EXT(_id, _group_id, _metadata)		      \
 	DEVLINK_TRAP_GENERIC(DROP, DROP, _id,				      \
-			     DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			     MLXSW_SP_TRAP_METADATA | (_metadata))
 
 #define MLXSW_SP_TRAP_DRIVER_DROP(_id, _group_id)			      \
 	DEVLINK_TRAP_DRIVER(DROP, DROP, DEVLINK_MLXSW_TRAP_ID_##_id,	      \
 			    DEVLINK_MLXSW_TRAP_NAME_##_id,		      \
-			    DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			    DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			    MLXSW_SP_TRAP_METADATA)
 
 #define MLXSW_SP_TRAP_EXCEPTION(_id, _group_id)		      \
 	DEVLINK_TRAP_GENERIC(EXCEPTION, TRAP, _id,			      \
-			     DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			     MLXSW_SP_TRAP_METADATA)
 
 #define MLXSW_SP_RXL_DISCARD(_id, _group_id)				      \
@@ -165,6 +165,13 @@ static void mlxsw_sp_rx_exception_listener(struct sk_buff *skb, u8 local_port,
 	MLXSW_RXL(mlxsw_sp_rx_exception_listener, _id,			      \
 		   _action, false, SP_##_group_id, SET_FW_DEFAULT)
 
+static const struct devlink_trap_group mlxsw_sp_trap_groups_arr[] = {
+	DEVLINK_TRAP_GROUP_GENERIC(L2_DROPS),
+	DEVLINK_TRAP_GROUP_GENERIC(L3_DROPS),
+	DEVLINK_TRAP_GROUP_GENERIC(TUNNEL_DROPS),
+	DEVLINK_TRAP_GROUP_GENERIC(ACL_DROPS),
+};
+
 static const struct devlink_trap mlxsw_sp_traps_arr[] = {
 	MLXSW_SP_TRAP_DROP(SMAC_MC, L2_DROPS),
 	MLXSW_SP_TRAP_DROP(VLAN_TAG_MISMATCH, L2_DROPS),
@@ -318,6 +325,7 @@ static int mlxsw_sp_trap_dummy_group_init(struct mlxsw_sp *mlxsw_sp)
 
 int mlxsw_sp_devlink_traps_init(struct mlxsw_sp *mlxsw_sp)
 {
+	size_t groups_count = ARRAY_SIZE(mlxsw_sp_trap_groups_arr);
 	struct devlink *devlink = priv_to_devlink(mlxsw_sp->core);
 	int err;
 
@@ -333,17 +341,33 @@ int mlxsw_sp_devlink_traps_init(struct mlxsw_sp *mlxsw_sp)
 		    ARRAY_SIZE(mlxsw_sp_listeners_arr)))
 		return -EINVAL;
 
-	return devlink_traps_register(devlink, mlxsw_sp_traps_arr,
-				      ARRAY_SIZE(mlxsw_sp_traps_arr),
-				      mlxsw_sp);
+	err = devlink_trap_groups_register(devlink, mlxsw_sp_trap_groups_arr,
+					   groups_count);
+	if (err)
+		return err;
+
+	err = devlink_traps_register(devlink, mlxsw_sp_traps_arr,
+				     ARRAY_SIZE(mlxsw_sp_traps_arr), mlxsw_sp);
+	if (err)
+		goto err_traps_register;
+
+	return 0;
+
+err_traps_register:
+	devlink_trap_groups_unregister(devlink, mlxsw_sp_trap_groups_arr,
+				       groups_count);
+	return err;
 }
 
 void mlxsw_sp_devlink_traps_fini(struct mlxsw_sp *mlxsw_sp)
 {
+	size_t groups_count = ARRAY_SIZE(mlxsw_sp_trap_groups_arr);
 	struct devlink *devlink = priv_to_devlink(mlxsw_sp->core);
 
 	devlink_traps_unregister(devlink, mlxsw_sp_traps_arr,
 				 ARRAY_SIZE(mlxsw_sp_traps_arr));
+	devlink_trap_groups_unregister(devlink, mlxsw_sp_trap_groups_arr,
+				       groups_count);
 }
 
 int mlxsw_sp_trap_init(struct mlxsw_core *mlxsw_core,
diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index f81c47377f32..7bfd0622cef1 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -381,22 +381,29 @@ enum {
 
 #define NSIM_TRAP_DROP(_id, _group_id)					      \
 	DEVLINK_TRAP_GENERIC(DROP, DROP, _id,				      \
-			     DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			     NSIM_TRAP_METADATA)
 #define NSIM_TRAP_DROP_EXT(_id, _group_id, _metadata)			      \
 	DEVLINK_TRAP_GENERIC(DROP, DROP, _id,				      \
-			     DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			     NSIM_TRAP_METADATA | (_metadata))
 #define NSIM_TRAP_EXCEPTION(_id, _group_id)				      \
 	DEVLINK_TRAP_GENERIC(EXCEPTION, TRAP, _id,			      \
-			     DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			     NSIM_TRAP_METADATA)
 #define NSIM_TRAP_DRIVER_EXCEPTION(_id, _group_id)			      \
 	DEVLINK_TRAP_DRIVER(EXCEPTION, TRAP, NSIM_TRAP_ID_##_id,	      \
 			    NSIM_TRAP_NAME_##_id,			      \
-			    DEVLINK_TRAP_GROUP_GENERIC(_group_id),	      \
+			    DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
 			    NSIM_TRAP_METADATA)
 
+static const struct devlink_trap_group nsim_trap_groups_arr[] = {
+	DEVLINK_TRAP_GROUP_GENERIC(L2_DROPS),
+	DEVLINK_TRAP_GROUP_GENERIC(L3_DROPS),
+	DEVLINK_TRAP_GROUP_GENERIC(BUFFER_DROPS),
+	DEVLINK_TRAP_GROUP_GENERIC(ACL_DROPS),
+};
+
 static const struct devlink_trap nsim_traps_arr[] = {
 	NSIM_TRAP_DROP(SMAC_MC, L2_DROPS),
 	NSIM_TRAP_DROP(VLAN_TAG_MISMATCH, L2_DROPS),
@@ -556,10 +563,15 @@ static int nsim_dev_traps_init(struct devlink *devlink)
 	nsim_trap_data->nsim_dev = nsim_dev;
 	nsim_dev->trap_data = nsim_trap_data;
 
+	err = devlink_trap_groups_register(devlink, nsim_trap_groups_arr,
+					   ARRAY_SIZE(nsim_trap_groups_arr));
+	if (err)
+		goto err_trap_items_free;
+
 	err = devlink_traps_register(devlink, nsim_traps_arr,
 				     ARRAY_SIZE(nsim_traps_arr), NULL);
 	if (err)
-		goto err_trap_items_free;
+		goto err_trap_groups_unregister;
 
 	INIT_DELAYED_WORK(&nsim_dev->trap_data->trap_report_dw,
 			  nsim_dev_trap_report_work);
@@ -568,6 +580,9 @@ static int nsim_dev_traps_init(struct devlink *devlink)
 
 	return 0;
 
+err_trap_groups_unregister:
+	devlink_trap_groups_unregister(devlink, nsim_trap_groups_arr,
+				       ARRAY_SIZE(nsim_trap_groups_arr));
 err_trap_items_free:
 	kfree(nsim_trap_data->trap_items_arr);
 err_trap_data_free:
@@ -582,6 +597,8 @@ static void nsim_dev_traps_exit(struct devlink *devlink)
 	cancel_delayed_work_sync(&nsim_dev->trap_data->trap_report_dw);
 	devlink_traps_unregister(devlink, nsim_traps_arr,
 				 ARRAY_SIZE(nsim_traps_arr));
+	devlink_trap_groups_unregister(devlink, nsim_trap_groups_arr,
+				       ARRAY_SIZE(nsim_trap_groups_arr));
 	kfree(nsim_dev->trap_data->trap_items_arr);
 	kfree(nsim_dev->trap_data);
 }
diff --git a/include/net/devlink.h b/include/net/devlink.h
index e68781b9b7d4..37230e23b5b0 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -553,7 +553,7 @@ struct devlink_trap_group {
  * @generic: Whether the trap is generic or not.
  * @id: Trap identifier.
  * @name: Trap name.
- * @group: Immutable packet trap group attributes.
+ * @init_group_id: Initial group identifier.
  * @metadata_cap: Metadata types that can be provided by the trap.
  *
  * Describes immutable attributes of packet traps that drivers register with
@@ -565,7 +565,7 @@ struct devlink_trap {
 	bool generic;
 	u16 id;
 	const char *name;
-	struct devlink_trap_group group;
+	u16 init_group_id;
 	u32 metadata_cap;
 };
 
@@ -694,18 +694,19 @@ enum devlink_trap_group_generic_id {
 #define DEVLINK_TRAP_GROUP_GENERIC_NAME_ACL_DROPS \
 	"acl_drops"
 
-#define DEVLINK_TRAP_GENERIC(_type, _init_action, _id, _group, _metadata_cap) \
+#define DEVLINK_TRAP_GENERIC(_type, _init_action, _id, _group_id,	      \
+			     _metadata_cap)				      \
 	{								      \
 		.type = DEVLINK_TRAP_TYPE_##_type,			      \
 		.init_action = DEVLINK_TRAP_ACTION_##_init_action,	      \
 		.generic = true,					      \
 		.id = DEVLINK_TRAP_GENERIC_ID_##_id,			      \
 		.name = DEVLINK_TRAP_GENERIC_NAME_##_id,		      \
-		.group = _group,					      \
+		.init_group_id = _group_id,				      \
 		.metadata_cap = _metadata_cap,				      \
 	}
 
-#define DEVLINK_TRAP_DRIVER(_type, _init_action, _id, _name, _group,	      \
+#define DEVLINK_TRAP_DRIVER(_type, _init_action, _id, _name, _group_id,	      \
 			    _metadata_cap)				      \
 	{								      \
 		.type = DEVLINK_TRAP_TYPE_##_type,			      \
@@ -713,7 +714,7 @@ enum devlink_trap_group_generic_id {
 		.generic = false,					      \
 		.id = _id,						      \
 		.name = _name,						      \
-		.group = _group,					      \
+		.init_group_id = _group_id,				      \
 		.metadata_cap = _metadata_cap,				      \
 	}
 
@@ -1057,6 +1058,12 @@ void devlink_trap_report(struct devlink *devlink, struct sk_buff *skb,
 			 void *trap_ctx, struct devlink_port *in_devlink_port,
 			 const struct flow_action_cookie *fa_cookie);
 void *devlink_trap_ctx_priv(void *trap_ctx);
+int devlink_trap_groups_register(struct devlink *devlink,
+				 const struct devlink_trap_group *groups,
+				 size_t groups_count);
+void devlink_trap_groups_unregister(struct devlink *devlink,
+				    const struct devlink_trap_group *groups,
+				    size_t groups_count);
 
 #if IS_ENABLED(CONFIG_NET_DEVLINK)
 
diff --git a/net/core/devlink.c b/net/core/devlink.c
index f51bebc8c33f..73bb8fbe3393 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -5456,16 +5456,14 @@ struct devlink_stats {
 /**
  * struct devlink_trap_group_item - Packet trap group attributes.
  * @group: Immutable packet trap group attributes.
- * @refcount: Number of trap items using the group.
  * @list: trap_group_list member.
  * @stats: Trap group statistics.
  *
  * Describes packet trap group attributes. Created by devlink during trap
- * registration.
+ * group registration.
  */
 struct devlink_trap_group_item {
 	const struct devlink_trap_group *group;
-	refcount_t refcount;
 	struct list_head list;
 	struct devlink_stats __percpu *stats;
 };
@@ -5818,6 +5816,19 @@ devlink_trap_group_item_lookup(struct devlink *devlink, const char *name)
 }
 
 static struct devlink_trap_group_item *
+devlink_trap_group_item_lookup_by_id(struct devlink *devlink, u16 id)
+{
+	struct devlink_trap_group_item *group_item;
+
+	list_for_each_entry(group_item, &devlink->trap_group_list, list) {
+		if (group_item->group->id == id)
+			return group_item;
+	}
+
+	return NULL;
+}
+
+static struct devlink_trap_group_item *
 devlink_trap_group_item_get_from_info(struct devlink *devlink,
 				      struct genl_info *info)
 {
@@ -5955,7 +5966,7 @@ __devlink_trap_group_action_set(struct devlink *devlink,
 	int err;
 
 	list_for_each_entry(trap_item, &devlink->trap_list, list) {
-		if (strcmp(trap_item->trap->group.name, group_name))
+		if (strcmp(trap_item->group_item->group->name, group_name))
 			continue;
 		err = __devlink_trap_action_set(devlink, trap_item,
 						trap_action, extack);
@@ -7866,7 +7877,7 @@ static int devlink_trap_driver_verify(const struct devlink_trap *trap)
 
 static int devlink_trap_verify(const struct devlink_trap *trap)
 {
-	if (!trap || !trap->name || !trap->group.name)
+	if (!trap || !trap->name)
 		return -EINVAL;
 
 	if (trap->generic)
@@ -7937,108 +7948,22 @@ devlink_trap_group_notify(struct devlink *devlink,
 				msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
 }
 
-static struct devlink_trap_group_item *
-devlink_trap_group_item_create(struct devlink *devlink,
-			       const struct devlink_trap_group *group)
-{
-	struct devlink_trap_group_item *group_item;
-	int err;
-
-	err = devlink_trap_group_verify(group);
-	if (err)
-		return ERR_PTR(err);
-
-	group_item = kzalloc(sizeof(*group_item), GFP_KERNEL);
-	if (!group_item)
-		return ERR_PTR(-ENOMEM);
-
-	group_item->stats = netdev_alloc_pcpu_stats(struct devlink_stats);
-	if (!group_item->stats) {
-		err = -ENOMEM;
-		goto err_stats_alloc;
-	}
-
-	group_item->group = group;
-	refcount_set(&group_item->refcount, 1);
-
-	if (devlink->ops->trap_group_init) {
-		err = devlink->ops->trap_group_init(devlink, group);
-		if (err)
-			goto err_group_init;
-	}
-
-	list_add_tail(&group_item->list, &devlink->trap_group_list);
-	devlink_trap_group_notify(devlink, group_item,
-				  DEVLINK_CMD_TRAP_GROUP_NEW);
-
-	return group_item;
-
-err_group_init:
-	free_percpu(group_item->stats);
-err_stats_alloc:
-	kfree(group_item);
-	return ERR_PTR(err);
-}
-
-static void
-devlink_trap_group_item_destroy(struct devlink *devlink,
-				struct devlink_trap_group_item *group_item)
-{
-	devlink_trap_group_notify(devlink, group_item,
-				  DEVLINK_CMD_TRAP_GROUP_DEL);
-	list_del(&group_item->list);
-	free_percpu(group_item->stats);
-	kfree(group_item);
-}
-
-static struct devlink_trap_group_item *
-devlink_trap_group_item_get(struct devlink *devlink,
-			    const struct devlink_trap_group *group)
-{
-	struct devlink_trap_group_item *group_item;
-
-	group_item = devlink_trap_group_item_lookup(devlink, group->name);
-	if (group_item) {
-		refcount_inc(&group_item->refcount);
-		return group_item;
-	}
-
-	return devlink_trap_group_item_create(devlink, group);
-}
-
-static void
-devlink_trap_group_item_put(struct devlink *devlink,
-			    struct devlink_trap_group_item *group_item)
-{
-	if (!refcount_dec_and_test(&group_item->refcount))
-		return;
-
-	devlink_trap_group_item_destroy(devlink, group_item);
-}
-
 static int
 devlink_trap_item_group_link(struct devlink *devlink,
 			     struct devlink_trap_item *trap_item)
 {
+	u16 group_id = trap_item->trap->init_group_id;
 	struct devlink_trap_group_item *group_item;
 
-	group_item = devlink_trap_group_item_get(devlink,
-						 &trap_item->trap->group);
-	if (IS_ERR(group_item))
-		return PTR_ERR(group_item);
+	group_item = devlink_trap_group_item_lookup_by_id(devlink, group_id);
+	if (WARN_ON_ONCE(!group_item))
+		return -EINVAL;
 
 	trap_item->group_item = group_item;
 
 	return 0;
 }
 
-static void
-devlink_trap_item_group_unlink(struct devlink *devlink,
-			       struct devlink_trap_item *trap_item)
-{
-	devlink_trap_group_item_put(devlink, trap_item->group_item);
-}
-
 static void devlink_trap_notify(struct devlink *devlink,
 				const struct devlink_trap_item *trap_item,
 				enum devlink_command cmd)
@@ -8101,7 +8026,6 @@ devlink_trap_register(struct devlink *devlink,
 	return 0;
 
 err_trap_init:
-	devlink_trap_item_group_unlink(devlink, trap_item);
 err_group_link:
 	free_percpu(trap_item->stats);
 err_stats_alloc:
@@ -8122,7 +8046,6 @@ static void devlink_trap_unregister(struct devlink *devlink,
 	list_del(&trap_item->list);
 	if (devlink->ops->trap_fini)
 		devlink->ops->trap_fini(devlink, trap, trap_item);
-	devlink_trap_item_group_unlink(devlink, trap_item);
 	free_percpu(trap_item->stats);
 	kfree(trap_item);
 }
@@ -8278,6 +8201,122 @@ void *devlink_trap_ctx_priv(void *trap_ctx)
 }
 EXPORT_SYMBOL_GPL(devlink_trap_ctx_priv);
 
+static int
+devlink_trap_group_register(struct devlink *devlink,
+			    const struct devlink_trap_group *group)
+{
+	struct devlink_trap_group_item *group_item;
+	int err;
+
+	if (devlink_trap_group_item_lookup(devlink, group->name))
+		return -EEXIST;
+
+	group_item = kzalloc(sizeof(*group_item), GFP_KERNEL);
+	if (!group_item)
+		return -ENOMEM;
+
+	group_item->stats = netdev_alloc_pcpu_stats(struct devlink_stats);
+	if (!group_item->stats) {
+		err = -ENOMEM;
+		goto err_stats_alloc;
+	}
+
+	group_item->group = group;
+
+	if (devlink->ops->trap_group_init) {
+		err = devlink->ops->trap_group_init(devlink, group);
+		if (err)
+			goto err_group_init;
+	}
+
+	list_add_tail(&group_item->list, &devlink->trap_group_list);
+	devlink_trap_group_notify(devlink, group_item,
+				  DEVLINK_CMD_TRAP_GROUP_NEW);
+
+	return 0;
+
+err_group_init:
+	free_percpu(group_item->stats);
+err_stats_alloc:
+	kfree(group_item);
+	return err;
+}
+
+static void
+devlink_trap_group_unregister(struct devlink *devlink,
+			      const struct devlink_trap_group *group)
+{
+	struct devlink_trap_group_item *group_item;
+
+	group_item = devlink_trap_group_item_lookup(devlink, group->name);
+	if (WARN_ON_ONCE(!group_item))
+		return;
+
+	devlink_trap_group_notify(devlink, group_item,
+				  DEVLINK_CMD_TRAP_GROUP_DEL);
+	list_del(&group_item->list);
+	free_percpu(group_item->stats);
+	kfree(group_item);
+}
+
+/**
+ * devlink_trap_groups_register - Register packet trap groups with devlink.
+ * @devlink: devlink.
+ * @groups: Packet trap groups.
+ * @groups_count: Count of provided packet trap groups.
+ *
+ * Return: Non-zero value on failure.
+ */
+int devlink_trap_groups_register(struct devlink *devlink,
+				 const struct devlink_trap_group *groups,
+				 size_t groups_count)
+{
+	int i, err;
+
+	mutex_lock(&devlink->lock);
+	for (i = 0; i < groups_count; i++) {
+		const struct devlink_trap_group *group = &groups[i];
+
+		err = devlink_trap_group_verify(group);
+		if (err)
+			goto err_trap_group_verify;
+
+		err = devlink_trap_group_register(devlink, group);
+		if (err)
+			goto err_trap_group_register;
+	}
+	mutex_unlock(&devlink->lock);
+
+	return 0;
+
+err_trap_group_register:
+err_trap_group_verify:
+	for (i--; i >= 0; i--)
+		devlink_trap_group_unregister(devlink, &groups[i]);
+	mutex_unlock(&devlink->lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(devlink_trap_groups_register);
+
+/**
+ * devlink_trap_groups_unregister - Unregister packet trap groups from devlink.
+ * @devlink: devlink.
+ * @groups: Packet trap groups.
+ * @groups_count: Count of provided packet trap groups.
+ */
+void devlink_trap_groups_unregister(struct devlink *devlink,
+				    const struct devlink_trap_group *groups,
+				    size_t groups_count)
+{
+	int i;
+
+	mutex_lock(&devlink->lock);
+	for (i = groups_count - 1; i >= 0; i--)
+		devlink_trap_group_unregister(devlink, &groups[i]);
+	mutex_unlock(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devlink_trap_groups_unregister);
+
 static void __devlink_compat_running_version(struct devlink *devlink,
 					     char *buf, size_t len)
 {