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Message-ID: <20190915085829.GE11194@splinter>
Date: Sun, 15 Sep 2019 11:58:29 +0300
From: Ido Schimmel <idosch@...sch.org>
To: Jiri Pirko <jiri@...nulli.us>
Cc: netdev@...r.kernel.org, davem@...emloft.net, idosch@...lanox.com,
dsahern@...il.com, jakub.kicinski@...ronome.com,
tariqt@...lanox.com, saeedm@...lanox.com, kuznet@....inr.ac.ru,
yoshfuji@...ux-ipv6.org, shuah@...nel.org, mlxsw@...lanox.com
Subject: Re: [patch net-next 14/15] net: devlink: allow to change namespaces
during reload
On Sat, Sep 14, 2019 at 08:46:07AM +0200, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@...lanox.com>
>
> All devlink instances are created in init_net and stay there for a
> lifetime. Allow user to be able to move devlink instances into
> namespaces during devlink reload operation. That ensures proper
> re-instantiation of driver objects, including netdevices.
>
> Signed-off-by: Jiri Pirko <jiri@...lanox.com>
> ---
> drivers/net/ethernet/mellanox/mlx4/main.c | 4 +
> include/uapi/linux/devlink.h | 4 +
> net/core/devlink.c | 155 ++++++++++++++++++++--
> 3 files changed, 155 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
> index ef3f3d06ff1e..989d0882aaa9 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/main.c
> @@ -3942,6 +3942,10 @@ static int mlx4_devlink_reload_down(struct devlink *devlink,
> struct mlx4_dev *dev = &priv->dev;
> struct mlx4_dev_persistent *persist = dev->persist;
>
> + if (!net_eq(devlink_net(devlink), &init_net)) {
> + NL_SET_ERR_MSG_MOD(extack, "Namespace change is not supported");
> + return -EOPNOTSUPP;
> + }
Are you sure that this actually works? I see that you first invoke
reload_down(), then set the new namespace, then invoke reload_up().
So shouldn't this check be done in reload_up() callback instead?
> if (persist->num_vfs)
> mlx4_warn(persist->dev, "Reload performed on PF, will cause reset on operating Virtual Functions\n");
> mlx4_restart_one_down(persist->pdev);
> diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
> index 580b7a2e40e1..b558ea88b766 100644
> --- a/include/uapi/linux/devlink.h
> +++ b/include/uapi/linux/devlink.h
> @@ -421,6 +421,10 @@ enum devlink_attr {
>
> DEVLINK_ATTR_RELOAD_FAILED, /* u8 0 or 1 */
>
> + DEVLINK_ATTR_NETNS_FD, /* u32 */
> + DEVLINK_ATTR_NETNS_PID, /* u32 */
> + DEVLINK_ATTR_NETNS_ID, /* u32 */
> +
> /* add new attributes above here, update the policy in devlink.c */
>
> __DEVLINK_ATTR_MAX,
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index 362cbbcca225..2a5db95cce3c 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -435,8 +435,16 @@ static void devlink_nl_post_doit(const struct genl_ops *ops,
> {
> struct devlink *devlink;
>
> - devlink = devlink_get_from_info(info);
> - if (~ops->internal_flags & DEVLINK_NL_FLAG_NO_LOCK)
> + /* When devlink changes netns, it would not be found
> + * by devlink_get_from_info(). So try if it is stored first.
> + */
> + if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_DEVLINK) {
> + devlink = info->user_ptr[0];
> + } else {
> + devlink = devlink_get_from_info(info);
> + WARN_ON(IS_ERR(devlink));
> + }
> + if (!IS_ERR(devlink) && ~ops->internal_flags & DEVLINK_NL_FLAG_NO_LOCK)
> mutex_unlock(&devlink->lock);
> mutex_unlock(&devlink_mutex);
> }
> @@ -2675,6 +2683,73 @@ devlink_resources_validate(struct devlink *devlink,
> return err;
> }
>
> +static struct net *devlink_netns_get(struct sk_buff *skb,
> + struct devlink *devlink,
> + struct genl_info *info)
> +{
> + struct nlattr *netns_pid_attr = info->attrs[DEVLINK_ATTR_NETNS_PID];
> + struct nlattr *netns_fd_attr = info->attrs[DEVLINK_ATTR_NETNS_FD];
> + struct nlattr *netns_id_attr = info->attrs[DEVLINK_ATTR_NETNS_ID];
> + struct net *net;
> +
> + if (!!netns_pid_attr + !!netns_fd_attr + !!netns_id_attr > 1) {
> + NL_SET_ERR_MSG(info->extack, "multiple netns identifying attributes specified");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (netns_pid_attr) {
> + net = get_net_ns_by_pid(nla_get_u32(netns_pid_attr));
> + } else if (netns_fd_attr) {
> + net = get_net_ns_by_fd(nla_get_u32(netns_fd_attr));
> + } else if (netns_id_attr) {
> + net = get_net_ns_by_id(sock_net(skb->sk),
> + nla_get_u32(netns_id_attr));
> + if (!net)
> + net = ERR_PTR(-EINVAL);
> + } else {
> + WARN_ON(1);
> + net = ERR_PTR(-EINVAL);
> + }
> + if (IS_ERR(net)) {
> + NL_SET_ERR_MSG(info->extack, "Unknown network namespace");
> + return ERR_PTR(-EINVAL);
> + }
> + if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) {
> + put_net(net);
> + return ERR_PTR(-EPERM);
> + }
> + return net;
> +}
> +
> +static void devlink_param_notify(struct devlink *devlink,
> + unsigned int port_index,
> + struct devlink_param_item *param_item,
> + enum devlink_command cmd);
> +
> +static void devlink_reload_netns_change(struct devlink *devlink,
> + struct net *dest_net)
> +{
> + struct devlink_param_item *param_item;
> +
> + /* Userspace needs to be notified about devlink objects
> + * removed from original and entering new network namespace.
> + * The rest of the devlink objects are re-created during
> + * reload process so the notifications are generated separatelly.
> + */
> +
> + list_for_each_entry(param_item, &devlink->param_list, list)
> + devlink_param_notify(devlink, 0, param_item,
> + DEVLINK_CMD_PARAM_DEL);
> + devlink_notify(devlink, DEVLINK_CMD_DEL);
> +
> + devlink_net_set(devlink, dest_net);
> +
> + devlink_notify(devlink, DEVLINK_CMD_NEW);
> + list_for_each_entry(param_item, &devlink->param_list, list)
> + devlink_param_notify(devlink, 0, param_item,
> + DEVLINK_CMD_PARAM_NEW);
> +}
> +
> static bool devlink_reload_supported(struct devlink *devlink)
> {
> return devlink->ops->reload_down && devlink->ops->reload_up;
> @@ -2695,9 +2770,27 @@ 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)
> +{
> + int err;
> +
> + err = devlink->ops->reload_down(devlink, 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);
> + devlink_reload_failed_set(devlink, !!err);
> + return err;
> +}
> +
> static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
> {
> struct devlink *devlink = info->user_ptr[0];
> + struct net *dest_net = NULL;
> int err;
>
> if (!devlink_reload_supported(devlink))
> @@ -2708,11 +2801,20 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
> NL_SET_ERR_MSG_MOD(info->extack, "resources size validation failed");
> return err;
> }
> - err = devlink->ops->reload_down(devlink, info->extack);
> - if (err)
> - return err;
> - err = devlink->ops->reload_up(devlink, info->extack);
> - devlink_reload_failed_set(devlink, !!err);
> +
> + if (info->attrs[DEVLINK_ATTR_NETNS_PID] ||
> + info->attrs[DEVLINK_ATTR_NETNS_FD] ||
> + info->attrs[DEVLINK_ATTR_NETNS_ID]) {
> + dest_net = devlink_netns_get(skb, devlink, info);
Hmm, you're never using 'devlink' there, so I guess you can drop it.
> + if (IS_ERR(dest_net))
> + return PTR_ERR(dest_net);
> + }
> +
> + err = devlink_reload(devlink, dest_net, info->extack);
> +
> + if (dest_net)
> + put_net(dest_net);
> +
> return err;
> }
>
> @@ -5794,6 +5896,9 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
> [DEVLINK_ATTR_TRAP_NAME] = { .type = NLA_NUL_STRING },
> [DEVLINK_ATTR_TRAP_ACTION] = { .type = NLA_U8 },
> [DEVLINK_ATTR_TRAP_GROUP_NAME] = { .type = NLA_NUL_STRING },
> + [DEVLINK_ATTR_NETNS_PID] = { .type = NLA_U32 },
> + [DEVLINK_ATTR_NETNS_FD] = { .type = NLA_U32 },
> + [DEVLINK_ATTR_NETNS_ID] = { .type = NLA_U32 },
> };
>
> static const struct genl_ops devlink_nl_ops[] = {
> @@ -8061,9 +8166,43 @@ int devlink_compat_switch_id_get(struct net_device *dev,
> return 0;
> }
>
> +static void __net_exit devlink_pernet_pre_exit(struct net *net)
> +{
> + struct devlink *devlink;
> + int err;
> +
> + /* In case network namespace is getting destroyed, reload
> + * all devlink instances from this namespace into init_net.
> + */
> + mutex_lock(&devlink_mutex);
> + list_for_each_entry(devlink, &devlink_list, list) {
> + if (net_eq(devlink_net(devlink), net)) {
> + if (WARN_ON(!devlink_reload_supported(devlink)))
> + continue;
> + err = devlink_reload(devlink, &init_net, NULL);
> + if (err)
> + pr_warn("Failed to reload devlink instance into init_net\n");
> + }
> + }
> + mutex_unlock(&devlink_mutex);
> +}
> +
> +static struct pernet_operations devlink_pernet_ops __net_initdata = {
> + .pre_exit = devlink_pernet_pre_exit,
> +};
> +
> static int __init devlink_init(void)
> {
> - return genl_register_family(&devlink_nl_family);
> + int err;
> +
> + err = genl_register_family(&devlink_nl_family);
> + if (err)
> + goto out;
> + err = register_pernet_subsys(&devlink_pernet_ops);
> +
> +out:
> + WARN_ON(err);
> + return err;
> }
>
> subsys_initcall(devlink_init);
> --
> 2.21.0
>
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