Re: [PATCH net-next v2 03/16] devlink: Add devlink reload limit option

[Vasundhara Volam]

On Wed, Oct 7, 2020 at 11:32 AM Moshe Shemesh <moshe@xxxxxxxxxxxx> wrote:
>
> Add reload limit to demand restrictions on reload actions.
> Reload limits supported:
> no_reset: No reset allowed, no down time allowed, no link flap and no
>           configuration is lost.
>
> By default reload limit is unspecified and so no constraints on reload
> actions are required.
>
> Some combinations of action and limit are invalid. For example, driver
> can not reinitialize its entities without any downtime.
>
> The no_reset reload limit will have usecase in this patchset to
> implement restricted fw_activate on mlx5.
>
> Have the uapi parameter of reload limit ready for future support of
> multiselection.
>
> Signed-off-by: Moshe Shemesh <moshe@xxxxxxxxxxxx>
> ---
> v1 -> v2:
> - Changed limit uapi parameter to bitfield32 for future support of
>   multiselection
> - Fixed reverse xmas tree
> RFCv5 -> v1:
> - Renamed supported_reload_actions_limit_levels to reload_limits
> - Renamed reload_action_limit_level to reload_limit
> - Change RELOAD_LIMIT_NONE to unspecified RELOAD_LIMIT_UNSPEC,
>   drivers don't need to declare support limits if they support only
>   no limitation
> - Use nla_poilcy range validation and remove the range check in
> devlink_nl_cmd_reload
> RFCv4 -> RFCv5:
> - Remove check DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_MAX
> - Added list of invalid action-limit_level combinations and add check to
>   supported actions and levels and check user request
> RFCv3 -> RFCv4:
> - New patch
> ---
>  drivers/net/ethernet/mellanox/mlx4/main.c     |  4 +-
>  .../net/ethernet/mellanox/mlx5/core/devlink.c |  4 +-
>  drivers/net/ethernet/mellanox/mlxsw/core.c    |  4 +-
>  drivers/net/netdevsim/dev.c                   |  6 +-
>  include/net/devlink.h                         |  8 +-
>  include/uapi/linux/devlink.h                  | 14 +++
>  net/core/devlink.c                            | 92 +++++++++++++++++--
>  7 files changed, 119 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
> index 649c5323cf9f..c326b434734e 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/main.c
> @@ -3947,6 +3947,7 @@ static int mlx4_restart_one_up(struct pci_dev *pdev, bool reload,
>
>  static int mlx4_devlink_reload_down(struct devlink *devlink, bool netns_change,
>                                     enum devlink_reload_action action,
> +                                   enum devlink_reload_limit limit,
>                                     struct netlink_ext_ack *extack)
>  {
>         struct mlx4_priv *priv = devlink_priv(devlink);
I don't see any check for limit. If users provide a limit that is not
supported by the driver, it seems to be simply ignored. Is it checked
somewhere else?


> @@ -3964,7 +3965,8 @@ static int mlx4_devlink_reload_down(struct devlink *devlink, bool netns_change,
>  }
>
>  static int mlx4_devlink_reload_up(struct devlink *devlink, enum devlink_reload_action action,
> -                                 u32 *actions_performed, struct netlink_ext_ack *extack)
> +                                 enum devlink_reload_limit limit, u32 *actions_performed,
> +                                 struct netlink_ext_ack *extack)
>  {
>         struct mlx4_priv *priv = devlink_priv(devlink);
>         struct mlx4_dev *dev = &priv->dev;
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
> index 1b248c01a209..0016041e8779 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
> @@ -86,6 +86,7 @@ mlx5_devlink_info_get(struct devlink *devlink, struct devlink_info_req *req,
>
>  static int mlx5_devlink_reload_down(struct devlink *devlink, bool netns_change,
>                                     enum devlink_reload_action action,
> +                                   enum devlink_reload_limit limit,
>                                     struct netlink_ext_ack *extack)
>  {
>         struct mlx5_core_dev *dev = devlink_priv(devlink);
> @@ -95,7 +96,8 @@ static int mlx5_devlink_reload_down(struct devlink *devlink, bool netns_change,
>  }
>
>  static int mlx5_devlink_reload_up(struct devlink *devlink, enum devlink_reload_action action,
> -                                 u32 *actions_performed, struct netlink_ext_ack *extack)
> +                                 enum devlink_reload_limit limit, u32 *actions_performed,
> +                                 struct netlink_ext_ack *extack)
>  {
>         struct mlx5_core_dev *dev = devlink_priv(devlink);
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
> index cd9f56c73827..7f77c2a71d1c 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/core.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
> @@ -1415,6 +1415,7 @@ mlxsw_devlink_info_get(struct devlink *devlink, struct devlink_info_req *req,
>  static int
>  mlxsw_devlink_core_bus_device_reload_down(struct devlink *devlink,
>                                           bool netns_change, enum devlink_reload_action action,
> +                                         enum devlink_reload_limit limit,
>                                           struct netlink_ext_ack *extack)
>  {
>         struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
> @@ -1428,7 +1429,8 @@ mlxsw_devlink_core_bus_device_reload_down(struct devlink *devlink,
>
>  static int
>  mlxsw_devlink_core_bus_device_reload_up(struct devlink *devlink, enum devlink_reload_action action,
> -                                       u32 *actions_performed, struct netlink_ext_ack *extack)
> +                                       enum devlink_reload_limit limit, u32 *actions_performed,
> +                                       struct netlink_ext_ack *extack)
>  {
>         struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
>
> diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
> index b57e35c4ef6f..d07061417675 100644
> --- a/drivers/net/netdevsim/dev.c
> +++ b/drivers/net/netdevsim/dev.c
> @@ -701,7 +701,8 @@ static int nsim_dev_reload_create(struct nsim_dev *nsim_dev,
>  static void nsim_dev_reload_destroy(struct nsim_dev *nsim_dev);
>
>  static int nsim_dev_reload_down(struct devlink *devlink, bool netns_change,
> -                               enum devlink_reload_action action, struct netlink_ext_ack *extack)
> +                               enum devlink_reload_action action, enum devlink_reload_limit limit,
> +                               struct netlink_ext_ack *extack)
>  {
>         struct nsim_dev *nsim_dev = devlink_priv(devlink);
>
> @@ -718,7 +719,8 @@ static int nsim_dev_reload_down(struct devlink *devlink, bool netns_change,
>  }
>
>  static int nsim_dev_reload_up(struct devlink *devlink, enum devlink_reload_action action,
> -                             u32 *actions_performed, struct netlink_ext_ack *extack)
> +                             enum devlink_reload_limit limit, u32 *actions_performed,
> +                             struct netlink_ext_ack *extack)
>  {
>         struct nsim_dev *nsim_dev = devlink_priv(devlink);
>
> diff --git a/include/net/devlink.h b/include/net/devlink.h
> index 93c535ae5a4b..9f5c37c391f8 100644
> --- a/include/net/devlink.h
> +++ b/include/net/devlink.h
> @@ -1151,10 +1151,14 @@ struct devlink_ops {
>          */
>         u32 supported_flash_update_params;
>         unsigned long reload_actions;
> +       unsigned long reload_limits;
>         int (*reload_down)(struct devlink *devlink, bool netns_change,
> -                          enum devlink_reload_action action, struct netlink_ext_ack *extack);
> +                          enum devlink_reload_action action,
> +                          enum devlink_reload_limit limit,
> +                          struct netlink_ext_ack *extack);
>         int (*reload_up)(struct devlink *devlink, enum devlink_reload_action action,
> -                        u32 *actions_performed, struct netlink_ext_ack *extack);
> +                        enum devlink_reload_limit limit, u32 *actions_performed,
> +                        struct netlink_ext_ack *extack);
>         int (*port_type_set)(struct devlink_port *devlink_port,
>                              enum devlink_port_type port_type);
>         int (*port_split)(struct devlink *devlink, unsigned int port_index,
> diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
> index 74bdad252c36..a0b8e24236c0 100644
> --- a/include/uapi/linux/devlink.h
> +++ b/include/uapi/linux/devlink.h
> @@ -311,6 +311,19 @@ enum devlink_reload_action {
>         DEVLINK_RELOAD_ACTION_MAX = __DEVLINK_RELOAD_ACTION_MAX - 1
>  };
>
> +enum devlink_reload_limit {
> +       DEVLINK_RELOAD_LIMIT_UNSPEC,    /* unspecified, no constraints */
> +       DEVLINK_RELOAD_LIMIT_NO_RESET,  /* No reset allowed, no down time allowed,
> +                                        * no link flap and no configuration is lost.
> +                                        */
> +
> +       /* Add new reload limit above */
> +       __DEVLINK_RELOAD_LIMIT_MAX,
> +       DEVLINK_RELOAD_LIMIT_MAX = __DEVLINK_RELOAD_LIMIT_MAX - 1
> +};
> +
> +#define DEVLINK_RELOAD_LIMITS_VALID_MASK (BIT(__DEVLINK_RELOAD_LIMIT_MAX) - 1)
> +
>  enum devlink_attr {
>         /* don't change the order or add anything between, this is ABI! */
>         DEVLINK_ATTR_UNSPEC,
> @@ -505,6 +518,7 @@ enum devlink_attr {
>
>         DEVLINK_ATTR_RELOAD_ACTION,             /* u8 */
>         DEVLINK_ATTR_RELOAD_ACTIONS_PERFORMED,  /* bitfield32 */
> +       DEVLINK_ATTR_RELOAD_LIMITS,             /* bitfield32 */
>
>         /* add new attributes above here, update the policy in devlink.c */
>
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index c026ed3519c9..28b63faa3c6b 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -479,12 +479,44 @@ static int devlink_nl_put_handle(struct sk_buff *msg, struct devlink *devlink)
>         return 0;
>  }
>
> +struct devlink_reload_combination {
> +       enum devlink_reload_action action;
> +       enum devlink_reload_limit limit;
> +};
> +
> +static const struct devlink_reload_combination devlink_reload_invalid_combinations[] = {
> +       {
> +               /* can't reinitialize driver with no down time */
> +               .action = DEVLINK_RELOAD_ACTION_DRIVER_REINIT,
> +               .limit = DEVLINK_RELOAD_LIMIT_NO_RESET,
> +       },
> +};
> +
> +static bool
> +devlink_reload_combination_is_invalid(enum devlink_reload_action action,
> +                                     enum devlink_reload_limit limit)
> +{
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(devlink_reload_invalid_combinations); i++)
> +               if (devlink_reload_invalid_combinations[i].action == action &&
> +                   devlink_reload_invalid_combinations[i].limit == limit)
> +                       return true;
> +       return false;
> +}
> +
>  static bool
>  devlink_reload_action_is_supported(struct devlink *devlink, enum devlink_reload_action action)
>  {
>         return test_bit(action, &devlink->ops->reload_actions);
>  }
>
> +static bool
> +devlink_reload_limit_is_supported(struct devlink *devlink, enum devlink_reload_limit limit)
> +{
> +       return test_bit(limit, &devlink->ops->reload_limits);
> +}
> +
>  static int devlink_nl_fill(struct sk_buff *msg, struct devlink *devlink,
>                            enum devlink_command cmd, u32 portid,
>                            u32 seq, int flags)
> @@ -2990,22 +3022,22 @@ bool devlink_is_reload_failed(const struct devlink *devlink)
>  EXPORT_SYMBOL_GPL(devlink_is_reload_failed);
>
>  static int devlink_reload(struct devlink *devlink, struct net *dest_net,
> -                         enum devlink_reload_action action, u32 *actions_performed,
> -                         struct netlink_ext_ack *extack)
> +                         enum devlink_reload_action action, enum devlink_reload_limit limit,
> +                         u32 *actions_performed, struct netlink_ext_ack *extack)
>  {
>         int err;
>
>         if (!devlink->reload_enabled)
>                 return -EOPNOTSUPP;
>
> -       err = devlink->ops->reload_down(devlink, !!dest_net, action, extack);
> +       err = devlink->ops->reload_down(devlink, !!dest_net, action, limit, extack);
>         if (err)
>                 return err;
>
>         if (dest_net && !net_eq(dest_net, devlink_net(devlink)))
>                 devlink_reload_netns_change(devlink, dest_net);
>
> -       err = devlink->ops->reload_up(devlink, action, actions_performed, extack);
> +       err = devlink->ops->reload_up(devlink, action, limit, actions_performed, extack);
>         devlink_reload_failed_set(devlink, !!err);
>         if (err)
>                 return err;
> @@ -3050,6 +3082,7 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
>  {
>         struct devlink *devlink = info->user_ptr[0];
>         enum devlink_reload_action action;
> +       enum devlink_reload_limit limit;
>         struct net *dest_net = NULL;
>         u32 actions_performed;
>         int err;
> @@ -3082,7 +3115,38 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
>                 return -EOPNOTSUPP;
>         }
>
> -       err = devlink_reload(devlink, dest_net, action, &actions_performed, info->extack);
> +       limit = DEVLINK_RELOAD_LIMIT_UNSPEC;
> +       if (info->attrs[DEVLINK_ATTR_RELOAD_LIMITS]) {
> +               struct nla_bitfield32 limits;
> +               u32 limits_selected;
> +
> +               limits = nla_get_bitfield32(info->attrs[DEVLINK_ATTR_RELOAD_LIMITS]);
> +               limits_selected = limits.value & limits.selector;
> +               if (!limits_selected) {
> +                       NL_SET_ERR_MSG_MOD(info->extack, "Invalid limit selected");
> +                       return -EINVAL;
> +               }
> +               for (limit = 0 ; limit <= DEVLINK_RELOAD_LIMIT_MAX ; limit++)
> +                       if (limits_selected & BIT(limit))
> +                               break;
> +               /* UAPI enables multiselection, but currently it is not used */
> +               if (limits_selected != BIT(limit)) {
> +                       NL_SET_ERR_MSG_MOD(info->extack,
> +                                          "Multiselection of limit is not supported");
> +                       return -EOPNOTSUPP;
> +               }
> +               if (!devlink_reload_limit_is_supported(devlink, limit)) {
> +                       NL_SET_ERR_MSG_MOD(info->extack,
> +                                          "Requested limit is not supported by the driver");
> +                       return -EOPNOTSUPP;
> +               }
> +               if (devlink_reload_combination_is_invalid(action, limit)) {
> +                       NL_SET_ERR_MSG_MOD(info->extack,
> +                                          "Requested limit is invalid for this action");
> +                       return -EINVAL;
> +               }
> +       }
> +       err = devlink_reload(devlink, dest_net, action, limit, &actions_performed, info->extack);
>
>         if (dest_net)
>                 put_net(dest_net);
> @@ -3090,7 +3154,7 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
>         if (err)
>                 return err;
>         /* For backward compatibility generate reply only if attributes used by user */
> -       if (!info->attrs[DEVLINK_ATTR_RELOAD_ACTION])
> +       if (!info->attrs[DEVLINK_ATTR_RELOAD_ACTION] && !info->attrs[DEVLINK_ATTR_RELOAD_LIMITS])
>                 return 0;
>
>         return devlink_nl_reload_actions_performed_snd(devlink, actions_performed,
> @@ -7347,6 +7411,7 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
>         [DEVLINK_ATTR_PORT_FUNCTION] = { .type = NLA_NESTED },
>         [DEVLINK_ATTR_RELOAD_ACTION] = NLA_POLICY_RANGE(NLA_U8, DEVLINK_RELOAD_ACTION_DRIVER_REINIT,
>                                                         DEVLINK_RELOAD_ACTION_MAX),
> +       [DEVLINK_ATTR_RELOAD_LIMITS] = NLA_POLICY_BITFIELD32(DEVLINK_RELOAD_LIMITS_VALID_MASK),
>  };
>
>  static const struct genl_small_ops devlink_nl_ops[] = {
> @@ -7682,6 +7747,9 @@ static struct genl_family devlink_nl_family __ro_after_init = {
>
>  static bool devlink_reload_actions_valid(const struct devlink_ops *ops)
>  {
> +       const struct devlink_reload_combination *comb;
> +       int i;
> +
>         if (!devlink_reload_supported(ops)) {
>                 if (WARN_ON(ops->reload_actions))
>                         return false;
> @@ -7692,6 +7760,17 @@ static bool devlink_reload_actions_valid(const struct devlink_ops *ops)
>                     ops->reload_actions & BIT(DEVLINK_RELOAD_ACTION_UNSPEC) ||
>                     ops->reload_actions >= BIT(__DEVLINK_RELOAD_ACTION_MAX)))
>                 return false;
> +
> +       if (WARN_ON(ops->reload_limits & BIT(DEVLINK_RELOAD_LIMIT_UNSPEC) ||
> +                   ops->reload_limits >= BIT(__DEVLINK_RELOAD_LIMIT_MAX)))
> +               return false;
> +
> +       for (i = 0; i < ARRAY_SIZE(devlink_reload_invalid_combinations); i++)  {
> +               comb = &devlink_reload_invalid_combinations[i];
> +               if (ops->reload_actions == BIT(comb->action) &&
> +                   ops->reload_limits == BIT(comb->limit))
> +                       return false;
> +       }
>         return true;
>  }
>
> @@ -10056,6 +10135,7 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
>                                 continue;
>                         err = devlink_reload(devlink, &init_net,
>                                              DEVLINK_RELOAD_ACTION_DRIVER_REINIT,
> +                                            DEVLINK_RELOAD_LIMIT_UNSPEC,
>                                              &actions_performed, NULL);
>                         if (err && err != -EOPNOTSUPP)
>                                 pr_warn("Failed to reload devlink instance into init_net\n");
> --
> 2.18.2
>

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