Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

93 lines (77 sloc) 2.265 kb
/*
* linux/ipc/ipcns_notifier.c
* Copyright (C) 2007 BULL SA. Nadia Derbey
*
* Notification mechanism for ipc namespaces:
* The callback routine registered in the memory chain invokes the ipcns
* notifier chain with the IPCNS_MEMCHANGED event.
* Each callback routine registered in the ipcns namespace recomputes msgmni
* for the owning namespace.
*/
#include <linux/msg.h>
#include <linux/rcupdate.h>
#include <linux/notifier.h>
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include "util.h"
static BLOCKING_NOTIFIER_HEAD(ipcns_chain);
static int ipcns_callback(struct notifier_block *self,
unsigned long action, void *arg)
{
struct ipc_namespace *ns;
switch (action) {
case IPCNS_MEMCHANGED: /* amount of lowmem has changed */
case IPCNS_CREATED:
case IPCNS_REMOVED:
/*
* It's time to recompute msgmni
*/
ns = container_of(self, struct ipc_namespace, ipcns_nb);
/*
* No need to get a reference on the ns: the 1st job of
* free_ipc_ns() is to unregister the callback routine.
* blocking_notifier_chain_unregister takes the wr lock to do
* it.
* When this callback routine is called the rd lock is held by
* blocking_notifier_call_chain.
* So the ipc ns cannot be freed while we are here.
*/
recompute_msgmni(ns);
break;
default:
break;
}
return NOTIFY_OK;
}
int register_ipcns_notifier(struct ipc_namespace *ns)
{
int rc;
memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb));
ns->ipcns_nb.notifier_call = ipcns_callback;
ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI;
rc = blocking_notifier_chain_register(&ipcns_chain, &ns->ipcns_nb);
if (!rc)
ns->auto_msgmni = 1;
return rc;
}
int cond_register_ipcns_notifier(struct ipc_namespace *ns)
{
int rc;
memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb));
ns->ipcns_nb.notifier_call = ipcns_callback;
ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI;
rc = blocking_notifier_chain_cond_register(&ipcns_chain,
&ns->ipcns_nb);
if (!rc)
ns->auto_msgmni = 1;
return rc;
}
void unregister_ipcns_notifier(struct ipc_namespace *ns)
{
blocking_notifier_chain_unregister(&ipcns_chain, &ns->ipcns_nb);
ns->auto_msgmni = 0;
}
int ipcns_notify(unsigned long val)
{
return blocking_notifier_call_chain(&ipcns_chain, val, NULL);
}
Jump to Line
Something went wrong with that request. Please try again.