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items: [PATCH 5/5] make netlink user -> kernel interface synchronious
items: Re: [PATCH 5/5] make netlink user -> kernel interface synchronious
items: Re: Re: [PATCH 5/5] make netlink user -> kernel interface synchronious

[PATCH 5/5] make netlink user -> kernel interface synchronious
type: item
description: This patch make processing netlink user -> kernel messages synchronious. This change was inspired by the talk with Alexey Kuznetsov about current netlink messages processing. He says that he was badly wrong when introduced asynchronious user -> kernel communication. The call netlink_unicast is the only path to send message to the kernel netlink socket. But, unfortunately, it is also used to send data to the user. Before this change the user message has been attached to the socket queue and sk->sk_data_ready was called. The process has been blocked until all pending messages were processed. The bad thing is that this processing may occur in the arbitrary process context. This patch changes nlk->data_ready callback to get 1 skb and force packet processing right in the netlink_unicast. Kernel -> user path in netlink_unicast remains untouched. EINTR processing for in netlink_run_queue was changed. It forces rtnl_lock drop, but the process remains in the cycle until the message will be fully processed. So, there is no need to use this kludges now. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> --- ./drivers/connector/connector.c.nlk6 2007-10-05 16:27:16.000000000 +0400 +++ ./drivers/connector/connector.c 2007-10-05 16:33:04.000000000 +0400 @@ -235,18 +235,6 @@ out: } /* - * Netlink socket input callback - dequeues the skbs and calls the - * main netlink receiving function. - */ -static void cn_input(struct sock *sk, int len) -{ - struct sk_buff *skb; - - while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) - cn_rx_skb(skb); -} - -/* * Notification routing. * * Gets id and checks if there are notification request for it's idx @@ -442,7 +430,7 @@ static int __devinit cn_init(void) struct cn_dev *dev = &cdev; int err; - dev->input = cn_input; + dev->input = cn_rx_skb; dev->id.idx = cn_idx; dev->id.val = cn_val; --- ./drivers/scsi/scsi_netlink.c.nlk6 2007-10-05 16:27:16.000000000 +0400 +++ ./drivers/scsi/scsi_netlink.c …
creator: den
date: 2007-10-05T14:47:44-00:00

Re: [PATCH 5/5] make netlink user -> kernel interface synchronious
type: item
description: Denis V. Lunev wrote: > This patch make processing netlink user -> kernel messages synchronious. > This change was inspired by the talk with Alexey Kuznetsov about current > netlink messages processing. He says that he was badly wrong when introduced > asynchronious user -> kernel communication. > > The call netlink_unicast is the only path to send message to the kernel > netlink socket. But, unfortunately, it is also used to send data to the > user. > > Before this change the user message has been attached to the socket queue > and sk->sk_data_ready was called. The process has been blocked until all > pending messages were processed. The bad thing is that this processing > may occur in the arbitrary process context. > > This patch changes nlk->data_ready callback to get 1 skb and force packet > processing right in the netlink_unicast. I guess the process credential stuff in netlink_skb_params can now be removed as well.
creator: Patrick McHardy
date: 2007-10-05T16:24:27-00:00

Re: Re: [PATCH 5/5] make netlink user -> kernel interface synchronious
type: item
description: Patrick McHardy wrote: > Denis V. Lunev wrote: >> This patch make processing netlink user -> kernel messages synchronious. >> This change was inspired by the talk with Alexey Kuznetsov about current >> netlink messages processing. He says that he was badly wrong when introduced >> asynchronious user -> kernel communication. >> >> The call netlink_unicast is the only path to send message to the kernel >> netlink socket. But, unfortunately, it is also used to send data to the >> user. >> >> Before this change the user message has been attached to the socket queue >> and sk->sk_data_ready was called. The process has been blocked until all >> pending messages were processed. The bad thing is that this processing >> may occur in the arbitrary process context. >> >> This patch changes nlk->data_ready callback to get 1 skb and force packet >> processing right in the netlink_unicast. > > > I guess the process credential stuff in netlink_skb_params can now > be removed as well. Yes, but I think the patch should be tested by more people before. Regards, Den
creator: dlunev
date: 2007-10-05T16:55:24-00:00

Re: [PATCH 5/5] make netlink user -> kernel interface synchronious
type: item
description: From: "Denis V. Lunev" <den@openvz.org> Date: Fri, 5 Oct 2007 18:48:44 +0400 > This patch make processing netlink user -> kernel messages synchronious. > This change was inspired by the talk with Alexey Kuznetsov about current > netlink messages processing. He says that he was badly wrong when introduced > asynchronious user -> kernel communication. > > The call netlink_unicast is the only path to send message to the kernel > netlink socket. But, unfortunately, it is also used to send data to the > user. > > Before this change the user message has been attached to the socket queue > and sk->sk_data_ready was called. The process has been blocked until all > pending messages were processed. The bad thing is that this processing > may occur in the arbitrary process context. > > This patch changes nlk->data_ready callback to get 1 skb and force packet > processing right in the netlink_unicast. > > Kernel -> user path in netlink_unicast remains untouched. > > EINTR processing for in netlink_run_queue was changed. It forces rtnl_lock > drop, but the process remains in the cycle until the message will be fully > processed. So, there is no need to use this kludges now. > > Signed-off-by: Denis V. Lunev <den@openvz.org> > Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Applied.
creator: davem
date: 2007-10-11T04:15:38-00:00