mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 21:24:00 +08:00
6546bc4279
The enhancement as asked for by Yasunori: if msgmni is set to a negative value, register it back into the ipcns notifier chain. A new interface has been added to the notification mechanism: notifier_chain_cond_register() registers a notifier block only if not already registered. With that new interface we avoid taking care of the states changes in procfs. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Mingming Cao <cmm@us.ibm.com> Cc: Pierre Peiffer <pierre.peiffer@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
/*
|
|
* 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)
|
|
{
|
|
memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb));
|
|
ns->ipcns_nb.notifier_call = ipcns_callback;
|
|
ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI;
|
|
return blocking_notifier_chain_register(&ipcns_chain, &ns->ipcns_nb);
|
|
}
|
|
|
|
int cond_register_ipcns_notifier(struct ipc_namespace *ns)
|
|
{
|
|
memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb));
|
|
ns->ipcns_nb.notifier_call = ipcns_callback;
|
|
ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI;
|
|
return blocking_notifier_chain_cond_register(&ipcns_chain,
|
|
&ns->ipcns_nb);
|
|
}
|
|
|
|
int unregister_ipcns_notifier(struct ipc_namespace *ns)
|
|
{
|
|
return blocking_notifier_chain_unregister(&ipcns_chain,
|
|
&ns->ipcns_nb);
|
|
}
|
|
|
|
int ipcns_notify(unsigned long val)
|
|
{
|
|
return blocking_notifier_call_chain(&ipcns_chain, val, NULL);
|
|
}
|