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Date: Sun, 15 Sep 2019 11:43:59 +0200
From: Jiri Pirko <jiri@...nulli.us>
To: Ido Schimmel <idosch@...sch.org>
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
Sun, Sep 15, 2019 at 10:58:29AM CEST, idosch@...sch.org wrote:
>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?
Correct, need to fix this. But I need to do this in down phase so the
objects are not removed.
>
>> 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.
Right, will do.
>
>> + 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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