Re: [PATCH net-next RFC v4 02/15] devlink: Add reload action limit level

[Moshe Shemesh]

On 9/14/2020 4:10 PM, Jiri Pirko wrote:
Mon, Sep 14, 2020 at 08:07:49AM CEST, mo...@mellanox.com wrote:
                
[..]

        
diff --git a/include/net/devlink.h b/include/net/devlink.h
index b09db891db04..dddd9ee5b8a9 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1012,9 +1012,13 @@ enum devlink_trap_group_generic_id {

struct devlink_ops {
        unsigned long supported_reload_actions;
+       unsigned long supported_reload_action_limit_levels;
        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_action_limit_level limit_level,
+                          struct netlink_ext_ack *extack);
        int (*reload_up)(struct devlink *devlink, enum devlink_reload_action 
action,
+                        enum devlink_reload_action_limit_level limit_level,
                         struct netlink_ext_ack *extack, unsigned long 
*actions_performed);
        int (*port_type_set)(struct devlink_port *devlink_port,
                             enum devlink_port_type port_type);
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index a6f64db0bdf3..b19686fd80ff 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -287,6 +287,22 @@ enum devlink_reload_action {
        DEVLINK_RELOAD_ACTION_MAX = __DEVLINK_RELOAD_ACTION_MAX - 1
};

+/**
+ * enum devlink_reload_action_limit_level - Reload action limit level.
+ * @DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_NONE: No constrains on action. Action 
may include
+ *                                          reset or downtime as needed.
+ * @DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_NO_RESET: No reset allowed, no down time 
allowed,
+ *                                              no link flap and no 
configuration is lost.
+ */
+enum devlink_reload_action_limit_level {
+       DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_NONE,
+       DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_NO_RESET,
+
+       /* Add new reload actions limit level above */
+       __DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_MAX,
+       DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_MAX = 
__DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_MAX - 1
+};
+
enum devlink_attr {
        /* don't change the order or add anything between, this is ABI! */
        DEVLINK_ATTR_UNSPEC,
@@ -478,6 +494,7 @@ enum devlink_attr {

        DEVLINK_ATTR_RELOAD_ACTION,             /* u8 */
        DEVLINK_ATTR_RELOAD_ACTIONS_PERFORMED,  /* nested */
+       DEVLINK_ATTR_RELOAD_ACTION_LIMIT_LEVEL, /* u8 */

        /* add new attributes above here, update the policy in devlink.c */

diff --git a/net/core/devlink.c b/net/core/devlink.c
index f4be1e1bf864..60aa0c4a3726 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -468,6 +468,13 @@ devlink_reload_action_is_supported(struct devlink 
*devlink, enum devlink_reload_
        return test_bit(action, &devlink->ops->supported_reload_actions);
}

+static bool
+devlink_reload_action_limit_level_is_supported(struct devlink *devlink,
+                                              enum 
devlink_reload_action_limit_level limit_level)
+{
+       return test_bit(limit_level, 
&devlink->ops->supported_reload_action_limit_levels);
+}
+
static int devlink_nl_fill(struct sk_buff *msg, struct devlink *devlink,
                           enum devlink_command cmd, u32 portid,
                           u32 seq, int flags)
@@ -2975,22 +2982,23 @@ 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, struct 
netlink_ext_ack *extack,
-                         unsigned long *actions_performed)
+                         enum devlink_reload_action action,
+                         enum devlink_reload_action_limit_level limit_level,
+                         struct netlink_ext_ack *extack, unsigned long 
*actions_performed)
{
        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_level, 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, extack, 
actions_performed);
+       err = devlink->ops->reload_up(devlink, action, limit_level, extack, 
actions_performed);
        devlink_reload_failed_set(devlink, !!err);
        return err;
}
@@ -3036,6 +3044,7 @@ devlink_nl_reload_actions_performed_fill(struct sk_buff 
*msg,

static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
{
+       enum devlink_reload_action_limit_level limit_level;
        struct devlink *devlink = info->user_ptr[0];
        enum devlink_reload_action action;
        unsigned long actions_performed;
@@ -3073,7 +3082,20 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, 
struct genl_info *info)
                return -EOPNOTSUPP;
        }

-       err = devlink_reload(devlink, dest_net, action, info->extack, 
&actions_performed);
+       if (info->attrs[DEVLINK_ATTR_RELOAD_ACTION_LIMIT_LEVEL])
+               limit_level = 
nla_get_u8(info->attrs[DEVLINK_ATTR_RELOAD_ACTION_LIMIT_LEVEL]);
+       else
+               limit_level = DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_NONE;
+
+       if (limit_level > DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_MAX) {
Again, not needed, devlink_reload_action_limit_level_is_supported() will
take case of it.
Ack.
+               NL_SET_ERR_MSG_MOD(info->extack, "Invalid limit level");
+               return -EINVAL;
+       } else if (!devlink_reload_action_limit_level_is_supported(devlink, 
limit_level)) {
+               NL_SET_ERR_MSG_MOD(info->extack, "Requested limit level is not 
supported");
"..by the driver"?
Ack.

+               return -EOPNOTSUPP;
+       }
+       err = devlink_reload(devlink, dest_net, action, limit_level, 
info->extack,
+                            &actions_performed);

        if (dest_net)
                put_net(dest_net);
@@ -7126,6 +7148,7 @@ static const struct nla_policy 
devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
        [DEVLINK_ATTR_TRAP_POLICER_BURST] = { .type = NLA_U64 },
        [DEVLINK_ATTR_PORT_FUNCTION] = { .type = NLA_NESTED },
        [DEVLINK_ATTR_RELOAD_ACTION] = { .type = NLA_U8 },
+       [DEVLINK_ATTR_RELOAD_ACTION_LIMIT_LEVEL] = { .type = NLA_U8 },
};

static const struct genl_ops devlink_nl_ops[] = {
@@ -7462,6 +7485,10 @@ static int devlink_reload_actions_verify(struct devlink 
*devlink)
        if (WARN_ON(ops->supported_reload_actions >= 
BIT(__DEVLINK_RELOAD_ACTION_MAX) ||
                    ops->supported_reload_actions <= 
BIT(DEVLINK_RELOAD_ACTION_UNSPEC)))
                return -EINVAL;
+       if (WARN_ON(!ops->supported_reload_action_limit_levels ||
+                   ops->supported_reload_action_limit_levels >=
+                   BIT(__DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_MAX)))
+               return -EINVAL;
I think that you can check some insane driver combinations like:
supports only driver-reinit, supports LEVEL_NO_RESET - that is
impossible and should be refused here.

Same goes to the actual user command call. If the user calls for
driver-reinit with LEVEL_NO_RESET, devlink should refuse with proper
extack


I actually holds a counter for this combination too, we said no_reset 
can apply to any action, but not really.


        return 0;
}

@@ -9756,7 +9783,8 @@ static void __net_exit devlink_pernet_pre_exit(struct net 
*net)
                        if (WARN_ON(!devlink_reload_supported(devlink)))
                                continue;
                        err = devlink_reload(devlink, &init_net,
-                                            
DEVLINK_RELOAD_ACTION_DRIVER_REINIT, NULL, NULL);
+                                            
DEVLINK_RELOAD_ACTION_DRIVER_REINIT,
+                                            
DEVLINK_RELOAD_ACTION_LIMIT_LEVEL_NONE, NULL, NULL);
                        if (err && err != -EOPNOTSUPP)
                                pr_warn("Failed to reload devlink instance into 
init_net\n");
                }
--
2.17.1