Date:   Mon, 14 Sep 2020 14:27:32 +0200
From:   Jiri Pirko <jiri@...nulli.us>
To:     Moshe Shemesh <moshe@...lanox.com>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Jiri Pirko <jiri@...lanox.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next RFC v4 01/15] devlink: Add reload action option
 to devlink reload command

Mon, Sep 14, 2020 at 08:07:48AM CEST, moshe@...lanox.com wrote:
>Add devlink reload action to allow the user to request a specific reload
>action. The action parameter is optional, if not specified then devlink
>driver re-init action is used (backward compatible).
>Note that when required to do firmware activation some drivers may need
>to reload the driver. On the other hand some drivers may need to reset
>the firmware to reinitialize the driver entities. Therefore, the devlink
>reload command returns the actions which were actually performed.
>Reload actions supported are:
>driver_reinit: driver entities re-initialization, applying devlink-param
>               and devlink-resource values.
>fw_activate: firmware activate.
>
>command examples:
>$devlink dev reload pci/0000:82:00.0 action driver_reinit
>reload_actions_performed:
>  driver_reinit
>
>$devlink dev reload pci/0000:82:00.0 action fw_activate
>reload_actions_performed:
>  driver_reinit fw_activate
>
>Signed-off-by: Moshe Shemesh <moshe@...lanox.com>
>---
>v3 -> v4:
>- Removed fw_activate_no_reset as an action (next patch adds limit
>  levels instead).
>- Renamed actions_done to actions_performed
>v2 -> v3:
>- Replace fw_live_patch action by fw_activate_no_reset
>- Devlink reload returns the actions done over netlink reply
>v1 -> v2:
>- Instead of reload levels driver,fw_reset,fw_live_patch have reload
>  actions driver_reinit,fw_activate,fw_live_patch
>- Remove driver default level, the action driver_reinit is the default
>  action for all drivers
>---
> drivers/net/ethernet/mellanox/mlx4/main.c     |  14 ++-
> .../net/ethernet/mellanox/mlx5/core/devlink.c |  15 ++-
> drivers/net/ethernet/mellanox/mlxsw/core.c    |  25 ++--
> drivers/net/netdevsim/dev.c                   |  16 ++-
> include/net/devlink.h                         |   7 +-
> include/uapi/linux/devlink.h                  |  19 +++
> net/core/devlink.c                            | 111 +++++++++++++++++-
> 7 files changed, 180 insertions(+), 27 deletions(-)
>
>diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
>index 70cf24ba71e4..aadf1676a0ed 100644
>--- a/drivers/net/ethernet/mellanox/mlx4/main.c
>+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
>@@ -3946,6 +3946,7 @@ static int mlx4_restart_one_up(struct pci_dev *pdev, bool reload,
> 			       struct devlink *devlink);
> 
> static int mlx4_devlink_reload_down(struct devlink *devlink, bool netns_change,
>+				    enum devlink_reload_action action,
> 				    struct netlink_ext_ack *extack)
> {
> 	struct mlx4_priv *priv = devlink_priv(devlink);
>@@ -3962,8 +3963,8 @@ static int mlx4_devlink_reload_down(struct devlink *devlink, bool netns_change,
> 	return 0;
> }
> 
>-static int mlx4_devlink_reload_up(struct devlink *devlink,
>-				  struct netlink_ext_ack *extack)
>+static int mlx4_devlink_reload_up(struct devlink *devlink, enum devlink_reload_action action,
>+				  struct netlink_ext_ack *extack, unsigned long *actions_performed)
> {
> 	struct mlx4_priv *priv = devlink_priv(devlink);
> 	struct mlx4_dev *dev = &priv->dev;
>@@ -3971,15 +3972,20 @@ static int mlx4_devlink_reload_up(struct devlink *devlink,
> 	int err;
> 
> 	err = mlx4_restart_one_up(persist->pdev, true, devlink);
>-	if (err)
>+	if (err) {
> 		mlx4_err(persist->dev, "mlx4_restart_one_up failed, ret=%d\n",
> 			 err);
>+		return err;
>+	}
>+	if (actions_performed)

Nit, pass the unsigned long allways (even when it would be unused) and
avoid check in every driver.


>+		*actions_performed = BIT(DEVLINK_RELOAD_ACTION_DRIVER_REINIT);
> 
>-	return err;
>+	return 0;
> }
> 
> static const struct devlink_ops mlx4_devlink_ops = {
> 	.port_type_set	= mlx4_devlink_port_type_set,
>+	.supported_reload_actions = BIT(DEVLINK_RELOAD_ACTION_DRIVER_REINIT),
> 	.reload_down	= mlx4_devlink_reload_down,
> 	.reload_up	= mlx4_devlink_reload_up,
> };

[..]


>@@ -2969,29 +2975,72 @@ 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,
>-			  struct netlink_ext_ack *extack)
>+			  enum devlink_reload_action action, 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, extack);
>+	err = devlink->ops->reload_down(devlink, !!dest_net, action, 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, extack);
>+	err = devlink->ops->reload_up(devlink, action, extack, actions_performed);

Here, please add a WARN_ON() check:
	WARN_ON(!(*actions_performed & action));

The requested action should be always performed.


> 	devlink_reload_failed_set(devlink, !!err);
> 	return err;
> }
> 
>+static int
>+devlink_nl_reload_actions_performed_fill(struct sk_buff *msg,
>+					 struct devlink *devlink,
>+					 unsigned long actions_performed,
>+					 enum devlink_command cmd, u32 portid,
>+					 u32 seq, int flags)
>+{
>+	struct nlattr *actions_performed_attr;
>+	void *hdr;
>+	int i;
>+
>+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
>+	if (!hdr)
>+		return -EMSGSIZE;
>+
>+	if (devlink_nl_put_handle(msg, devlink))
>+		goto genlmsg_cancel;
>+
>+	actions_performed_attr = nla_nest_start(msg, DEVLINK_ATTR_RELOAD_ACTIONS_PERFORMED);
>+	if (!actions_performed_attr)
>+		goto genlmsg_cancel;
>+
>+	for (i = 0; i <= DEVLINK_RELOAD_ACTION_MAX; i++) {
>+		if (!test_bit(i, &actions_performed))
>+			continue;
>+		if (nla_put_u8(msg, DEVLINK_ATTR_RELOAD_ACTION, i))
>+			goto actions_performed_nest_cancel;
>+	}
>+	nla_nest_end(msg, actions_performed_attr);
>+	genlmsg_end(msg, hdr);
>+	return 0;
>+
>+actions_performed_nest_cancel:
>+	nla_nest_cancel(msg, actions_performed_attr);
>+genlmsg_cancel:
>+	genlmsg_cancel(msg, hdr);
>+	return -EMSGSIZE;
>+}
>+
> 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;
>+	unsigned long actions_performed;
> 	struct net *dest_net = NULL;
>+	struct sk_buff *msg;
> 	int err;
> 
> 	if (!devlink_reload_supported(devlink))
>@@ -3011,12 +3060,41 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
> 			return PTR_ERR(dest_net);
> 	}
> 
>-	err = devlink_reload(devlink, dest_net, info->extack);
>+	if (info->attrs[DEVLINK_ATTR_RELOAD_ACTION])
>+		action = nla_get_u8(info->attrs[DEVLINK_ATTR_RELOAD_ACTION]);
>+	else
>+		action = DEVLINK_RELOAD_ACTION_DRIVER_REINIT;
>+
>+	if (action == DEVLINK_RELOAD_ACTION_UNSPEC || action > DEVLINK_RELOAD_ACTION_MAX) {
>+		NL_SET_ERR_MSG_MOD(info->extack, "Invalid reload action");

Hmm, I understand the unspec check, but the max check is not needed. The
following check will take care of it.


>+		return -EINVAL;
>+	} else if (!devlink_reload_action_is_supported(devlink, action)) {
>+		NL_SET_ERR_MSG_MOD(info->extack, "Requested reload action is not supported");

".. by the driver" ?
	

>+		return -EOPNOTSUPP;
>+	}
>+
>+	err = devlink_reload(devlink, dest_net, action, info->extack, &actions_performed);
> 
> 	if (dest_net)
> 		put_net(dest_net);
> 
>-	return err;
>+	if (err)
>+		return err;
>+
>+	WARN_ON(!actions_performed);
>+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+	if (!msg)
>+		return -ENOMEM;
>+
>+	err = devlink_nl_reload_actions_performed_fill(msg, devlink, actions_performed,
>+						       DEVLINK_CMD_RELOAD, info->snd_portid,
>+						       info->snd_seq, 0);
>+	if (err) {
>+		nlmsg_free(msg);
>+		return err;
>+	}
>+
>+	return genlmsg_reply(msg, info);
> }
> 
> static int devlink_nl_flash_update_fill(struct sk_buff *msg,
>@@ -7047,6 +7125,7 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
> 	[DEVLINK_ATTR_TRAP_POLICER_RATE] = { .type = NLA_U64 },
> 	[DEVLINK_ATTR_TRAP_POLICER_BURST] = { .type = NLA_U64 },
> 	[DEVLINK_ATTR_PORT_FUNCTION] = { .type = NLA_NESTED },
>+	[DEVLINK_ATTR_RELOAD_ACTION] = { .type = NLA_U8 },
> };
> 
> static const struct genl_ops devlink_nl_ops[] = {
>@@ -7372,6 +7451,20 @@ static struct genl_family devlink_nl_family __ro_after_init = {
> 	.n_mcgrps	= ARRAY_SIZE(devlink_nl_mcgrps),
> };
> 
>+static int devlink_reload_actions_verify(struct devlink *devlink)
>+{
>+	const struct devlink_ops *ops;
>+
>+	if (!devlink_reload_supported(devlink))

If reload is not supported, the supported_reload_actions should be 0.
Please check that with WARN_ON too.


>+		return 0;
>+
>+	ops = devlink->ops;
>+	if (WARN_ON(ops->supported_reload_actions >= BIT(__DEVLINK_RELOAD_ACTION_MAX) ||
>+		    ops->supported_reload_actions <= BIT(DEVLINK_RELOAD_ACTION_UNSPEC)))
>+		return -EINVAL;
>+	return 0;
>+}
>+
> /**
>  *	devlink_alloc - Allocate new devlink instance resources
>  *
>@@ -7392,6 +7485,11 @@ struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size)
> 	if (!devlink)
> 		return NULL;
> 	devlink->ops = ops;
>+	if (devlink_reload_actions_verify(devlink)) {

Move this check to the beginning. You don't need devlink instance for
the check, just ops.

also, your devlink_reload_actions_verify() function returns
0/-ESOMETHING. Treat it accordingly here.


>+		kfree(devlink);
>+		return NULL;
>+	}
>+
> 	xa_init_flags(&devlink->snapshot_ids, XA_FLAGS_ALLOC);
> 	__devlink_net_set(devlink, &init_net);
> 	INIT_LIST_HEAD(&devlink->port_list);
>@@ -9657,7 +9755,8 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
> 		if (net_eq(devlink_net(devlink), net)) {
> 			if (WARN_ON(!devlink_reload_supported(devlink)))
> 				continue;
>-			err = devlink_reload(devlink, &init_net, NULL);
>+			err = devlink_reload(devlink, &init_net,
>+					     DEVLINK_RELOAD_ACTION_DRIVER_REINIT, NULL, NULL);
> 			if (err && err != -EOPNOTSUPP)
> 				pr_warn("Failed to reload devlink instance into init_net\n");
> 		}
>-- 
>2.17.1
>

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