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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a connector that reports fork, exec, id change, and exit
events for all processes to userspace. It replaces the fork_advisor patch
that ELSA is currently using. Applications that may find these events
useful include accounting/auditing (e.g. ELSA), system activity monitoring
(e.g. top), security, and resource management (e.g. CKRM).
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- added typedef unsigned int __nocast gfp_t;
- replaced __nocast uses for gfp flags with gfp_t - it gives exactly
the same warnings as far as sparse is concerned, doesn't change
generated code (from gcc point of view we replaced unsigned int with
typedef) and documents what's going on far better.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix implicit nocast warnings in connector code:
drivers/connector/connector.c:102:24: warning: implicit cast to nocast type
drivers/connector/connector.c:114:45: warning: implicit cast to nocast type
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If input message rate from userspace is too high, do not drop them,
but try to deliver using work queue allocation.
Failing there is some kind of congestion control.
It also removes warn_on on this condition, which scares people.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Kernel connector - new userspace <-> kernel space easy to use
communication module which implements easy to use bidirectional
message bus using netlink as it's backend. Connector was created to
eliminate complex skb handling both in send and receive message bus
direction.
Connector driver adds possibility to connect various agents using as
one of it's backends netlink based network. One must register
callback and identifier. When driver receives special netlink message
with appropriate identifier, appropriate callback will be called.
From the userspace point of view it's quite straightforward:
socket();
bind();
send();
recv();
But if kernelspace want to use full power of such connections, driver
writer must create special sockets, must know about struct sk_buff
handling... Connector allows any kernelspace agents to use netlink
based networking for inter-process communication in a significantly
easier way:
int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));
void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);
struct cb_id
{
__u32 idx;
__u32 val;
};
idx and val are unique identifiers which must be registered in
connector.h for in-kernel usage. void (*callback) (void *) - is a
callback function which will be called when message with above idx.val
will be received by connector core.
Using connector completely hides low-level transport layer from it's
users.
Connector uses new netlink ability to have many groups in one socket.
[ Incorporating many cleanups and fixes by myself and
Andrew Morton -DaveM ]
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
