net/mlx5: Add support for devlink traps in mlx5 core driver

Add devlink traps infra-structure to mlx5 core driver. Add traps list to
mlx5_priv and corresponding API:
 - mlx5_devlink_trap_report() to wrap trap reports to devlink
 - mlx5_devlink_trap_get_num_active() to decide whether to open/close trap
   resources.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlx5/core/devlink.c

@@ -168,6 +168,56 @@ static int mlx5_devlink_reload_up(struct devlink *devlink, enum devlink_reload_a
 	return 0;
 }
 
+static struct mlx5_devlink_trap *mlx5_find_trap_by_id(struct mlx5_core_dev *dev, int trap_id)
+{
+	struct mlx5_devlink_trap *dl_trap;
+
+	list_for_each_entry(dl_trap, &dev->priv.traps, list)
+		if (dl_trap->trap.id == trap_id)
+			return dl_trap;
+
+	return NULL;
+}
+
+static int mlx5_devlink_trap_init(struct devlink *devlink, const struct devlink_trap *trap,
+				  void *trap_ctx)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	struct mlx5_devlink_trap *dl_trap;
+
+	dl_trap = kzalloc(sizeof(*dl_trap), GFP_KERNEL);
+	if (!dl_trap)
+		return -ENOMEM;
+
+	dl_trap->trap.id = trap->id;
+	dl_trap->trap.action = DEVLINK_TRAP_ACTION_DROP;
+	dl_trap->item = trap_ctx;
+
+	if (mlx5_find_trap_by_id(dev, trap->id)) {
+		kfree(dl_trap);
+		mlx5_core_err(dev, "Devlink trap: Trap 0x%x already found", trap->id);
+		return -EEXIST;
+	}
+
+	list_add_tail(&dl_trap->list, &dev->priv.traps);
+	return 0;
+}
+
+static void mlx5_devlink_trap_fini(struct devlink *devlink, const struct devlink_trap *trap,
+				   void *trap_ctx)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	struct mlx5_devlink_trap *dl_trap;
+
+	dl_trap = mlx5_find_trap_by_id(dev, trap->id);
+	if (!dl_trap) {
+		mlx5_core_err(dev, "Devlink trap: Missing trap id 0x%x", trap->id);
+		return;
+	}
+	list_del(&dl_trap->list);
+	kfree(dl_trap);
+}
+
 static const struct devlink_ops mlx5_devlink_ops = {
 #ifdef CONFIG_MLX5_ESWITCH
 	.eswitch_mode_set = mlx5_devlink_eswitch_mode_set,
@@ -186,8 +236,42 @@ static const struct devlink_ops mlx5_devlink_ops = {
 	.reload_limits = BIT(DEVLINK_RELOAD_LIMIT_NO_RESET),
 	.reload_down = mlx5_devlink_reload_down,
 	.reload_up = mlx5_devlink_reload_up,
+	.trap_init = mlx5_devlink_trap_init,
+	.trap_fini = mlx5_devlink_trap_fini,
 };
 
+void mlx5_devlink_trap_report(struct mlx5_core_dev *dev, int trap_id, struct sk_buff *skb,
+			      struct devlink_port *dl_port)
+{
+	struct devlink *devlink = priv_to_devlink(dev);
+	struct mlx5_devlink_trap *dl_trap;
+
+	dl_trap = mlx5_find_trap_by_id(dev, trap_id);
+	if (!dl_trap) {
+		mlx5_core_err(dev, "Devlink trap: Report on invalid trap id 0x%x", trap_id);
+		return;
+	}
+
+	if (dl_trap->trap.action != DEVLINK_TRAP_ACTION_TRAP) {
+		mlx5_core_dbg(dev, "Devlink trap: Trap id %d has action %d", trap_id,
+			      dl_trap->trap.action);
+		return;
+	}
+	devlink_trap_report(devlink, skb, dl_trap->item, dl_port, NULL);
+}
+
+int mlx5_devlink_trap_get_num_active(struct mlx5_core_dev *dev)
+{
+	struct mlx5_devlink_trap *dl_trap;
+	int count = 0;
+
+	list_for_each_entry(dl_trap, &dev->priv.traps, list)
+		if (dl_trap->trap.action == DEVLINK_TRAP_ACTION_TRAP)
+			count++;
+
+	return count;
+}
+
 struct devlink *mlx5_devlink_alloc(void)
 {
 	return devlink_alloc(&mlx5_devlink_ops, sizeof(struct mlx5_core_dev));

drivers/net/ethernet/mellanox/mlx5/core/devlink.h

@@ -12,6 +12,22 @@ enum mlx5_devlink_param_id {
 	MLX5_DEVLINK_PARAM_ID_ESW_LARGE_GROUP_NUM,
 };
 
+struct mlx5_trap_ctx {
+	int id;
+	int action;
+};
+
+struct mlx5_devlink_trap {
+	struct mlx5_trap_ctx trap;
+	void *item;
+	struct list_head list;
+};
+
+struct mlx5_core_dev;
+void mlx5_devlink_trap_report(struct mlx5_core_dev *dev, int trap_id, struct sk_buff *skb,
+			      struct devlink_port *dl_port);
+int mlx5_devlink_trap_get_num_active(struct mlx5_core_dev *dev);
+
 struct devlink *mlx5_devlink_alloc(void);
 void mlx5_devlink_free(struct devlink *devlink);
 int mlx5_devlink_register(struct devlink *devlink, struct device *dev);

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -1305,6 +1305,8 @@ static int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx)
 
 	priv->dbg_root = debugfs_create_dir(dev_name(dev->device),
 					    mlx5_debugfs_root);
+	INIT_LIST_HEAD(&priv->traps);
+
 	err = mlx5_health_init(dev);
 	if (err)
 		goto err_health_init;

include/linux/mlx5/driver.h

@@ -564,6 +564,7 @@ struct mlx5_priv {
 	int			host_pf_pages;
 
 	struct mlx5_core_health health;
+	struct list_head	traps;
 
 	/* start: qp staff */
 	struct dentry	       *qp_debugfs;