Re: [PATCH 1/2 v3] net: add uevent socket member

Christian Brauner
2018-03-19T11:59:42Z

On Mon, Mar 19, 2018 at 02:53:09PM +0300, Kirill Tkhai wrote:
> 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?

Yeah, I can remove it and resend it now.

Christian

>
> > }
> >
> > static struct pernet_operations uevent_net_ops = {
> >
>
> Kirill