Messages in this thread Patch in this message | | | Date | Wed, 14 Feb 2024 08:48:29 +0000 | Subject | [PATCH 2/2] kobject: reduce uevent_sock_mutex scope | From | Eric Dumazet <> |
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This is a followup of commit a3498436b3a0 ("netns: restrict uevents")
- uevent_sock_mutex no longer protects uevent_seqnum thanks to prior patch in the series.
- uevent_net_broadcast() can run without holding uevent_sock_mutex.
- Instead of grabbing uevent_sock_mutex before calling kobject_uevent_net_broadcast(), we can move the mutex_lock(&uevent_sock_mutex) to the place we iterate over uevent_sock_list : uevent_net_broadcast_untagged().
After this patch, typical netdevice creations and destructions calling uevent_net_broadcast_tagged() no longer need to acquire uevent_sock_mutex.
Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Christian Brauner <brauner@kernel.org> --- lib/kobject_uevent.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 9cb1a7fdaeba4fc5c698fbe84f359fb305345be1..03b427e2707e357ab12abeb9da234432c4bc0fb3 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -42,10 +42,9 @@ struct uevent_sock { #ifdef CONFIG_NET static LIST_HEAD(uevent_sock_list); -#endif - /* This lock protects uevent_sock_list */ static DEFINE_MUTEX(uevent_sock_mutex); +#endif /* the strings here must match the enum in include/linux/kobject.h */ static const char *kobject_actions[] = { @@ -315,6 +314,7 @@ static int uevent_net_broadcast_untagged(struct kobj_uevent_env *env, int retval = 0; /* send netlink message */ + mutex_lock(&uevent_sock_mutex); list_for_each_entry(ue_sk, &uevent_sock_list, list) { struct sock *uevent_sock = ue_sk->sk; @@ -334,6 +334,7 @@ static int uevent_net_broadcast_untagged(struct kobj_uevent_env *env, if (retval == -ENOBUFS || retval == -ESRCH) retval = 0; } + mutex_unlock(&uevent_sock_mutex); consume_skb(skb); return retval; @@ -589,10 +590,8 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, if (retval) goto exit; - mutex_lock(&uevent_sock_mutex); retval = kobject_uevent_net_broadcast(kobj, env, action_string, devpath); - mutex_unlock(&uevent_sock_mutex); #ifdef CONFIG_UEVENT_HELPER /* call uevent_helper, usually only enabled during early boot */ @@ -743,9 +742,7 @@ static int uevent_net_rcv_skb(struct sk_buff *skb, struct nlmsghdr *nlh, return -EPERM; } - mutex_lock(&uevent_sock_mutex); ret = uevent_net_broadcast(net->uevent_sock->sk, skb, extack); - mutex_unlock(&uevent_sock_mutex); return ret; } -- 2.43.0.687.g38aa6559b0-goog
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