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Subject: Re: [PATCH 1/2 v3] net: add uevent socket member
To:     Christian Brauner <christian.brauner@ubuntu.com>,
        ebiederm@xmission.com, gregkh@linuxfoundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     serge@hallyn.com, avagin@virtuozzo.com
References: <20180317110826.1581-1-christian.brauner@ubuntu.com>
From:   Kirill Tkhai <ktkhai@virtuozzo.com>
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Date:   Mon, 19 Mar 2018 14:53:09 +0300
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Thanks for doing this. One small comment below.

On 17.03.2018 14:08, Christian Brauner wrote:
> This commit adds struct uevent_sock to struct net. Since struct uevent_sock
> records the position of the uevent socket in the uevent socket list we can
> trivially remove it from the uevent socket list during cleanup. This speeds
> up the old removal codepath.
> Note, list_del() will hit __list_del_entry_valid() in its call chain which
> will validate that the element is a member of the list. If it isn't it will
> take care that the list is not modified.
> 
> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> ---
> Changelog v2->v3:
> * patch added
>   This patch was split out of the follow up patch
>   Subject: [PATCH 2/2 v3] netns: send uevent messages
> 
> Changelog v1->v2:
> * patch not present
> 
> Changelog v0->v1:
> * patch not present
> ---
>  include/net/net_namespace.h |  4 +++-
>  lib/kobject_uevent.c        | 19 +++++++++----------
>  2 files changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
> index f306b2aa15a4..abd7d91bffac 100644
> --- a/include/net/net_namespace.h
> +++ b/include/net/net_namespace.h
> @@ -40,7 +40,7 @@ struct net_device;
>  struct sock;
>  struct ctl_table_header;
>  struct net_generic;
> -struct sock;
> +struct uevent_sock;
>  struct netns_ipvs;
>  
>  
> @@ -79,6 +79,8 @@ struct net {
>  	struct sock 		*rtnl;			/* rtnetlink socket */
>  	struct sock		*genl_sock;
>  
> +	struct uevent_sock	*uevent_sock;		/* uevent socket */
> +
>  	struct list_head 	dev_base_head;
>  	struct hlist_head 	*dev_name_head;
>  	struct hlist_head	*dev_index_head;
> diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
> index 9fe6ec8fda28..cbdc60542cab 100644
> --- a/lib/kobject_uevent.c
> +++ b/lib/kobject_uevent.c
> @@ -32,11 +32,13 @@ u64 uevent_seqnum;
>  #ifdef CONFIG_UEVENT_HELPER
>  char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
>  #endif
> -#ifdef CONFIG_NET
> +
>  struct uevent_sock {
>  	struct list_head list;
>  	struct sock *sk;
>  };
> +
> +#ifdef CONFIG_NET
>  static LIST_HEAD(uevent_sock_list);
>  #endif
>  
> @@ -621,6 +623,9 @@ static int uevent_net_init(struct net *net)
>  		kfree(ue_sk);
>  		return -ENODEV;
>  	}
> +
> +	net->uevent_sock = ue_sk;
> +
>  	mutex_lock(&uevent_sock_mutex);
>  	list_add_tail(&ue_sk->list, &uevent_sock_list);
>  	mutex_unlock(&uevent_sock_mutex);
> @@ -629,22 +634,16 @@ static int uevent_net_init(struct net *net)
>  
>  static void uevent_net_exit(struct net *net)
>  {
> -	struct uevent_sock *ue_sk;
> +	struct uevent_sock *ue_sk = net->uevent_sock;
>  
>  	mutex_lock(&uevent_sock_mutex);
> -	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
> -		if (sock_net(ue_sk->sk) == net)
> -			goto found;
> -	}
> -	mutex_unlock(&uevent_sock_mutex);
> -	return;
> -
> -found:
>  	list_del(&ue_sk->list);
>  	mutex_unlock(&uevent_sock_mutex);
>  
>  	netlink_kernel_release(ue_sk->sk);
>  	kfree(ue_sk);
> +
> +	return;

There is end of function. Doesn't return is excess here?

>  }
>  
>  static struct pernet_operations uevent_net_ops = {
> 

Kirill