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authorNadia Derbey <Nadia.Derbey@bull.net>2008-04-29 01:00:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:13 -0700
commit6546bc4279241e8fa432de1bb63a4f6f791fd669 (patch)
tree308f5c1621b1019a44800622ffc468a372f09434 /ipc
parent91cfb2b4b57816de0c96de417b3238249f0b125f (diff)
downloadconfigs-6546bc4279241e8fa432de1bb63a4f6f791fd669.tar.gz
ipc: re-enable msgmni automatic recomputing msgmni if set to negative
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>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/ipc_sysctl.c45
-rw-r--r--ipc/ipcns_notifier.c9
2 files changed, 44 insertions, 10 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index d12ff5cd2a0..d3497465cc0 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -15,6 +15,8 @@
#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <linux/ipc_namespace.h>
+#include <linux/msg.h>
+#include "util.h"
static void *get_ipc(ctl_table *table)
{
@@ -24,6 +26,27 @@ static void *get_ipc(ctl_table *table)
return which;
}
+/*
+ * Routine that is called when a tunable has successfully been changed by
+ * hand and it has a callback routine registered on the ipc namespace notifier
+ * chain: we don't want such tunables to be recomputed anymore upon memory
+ * add/remove or ipc namespace creation/removal.
+ * They can come back to a recomputable state by being set to a <0 value.
+ */
+static void tunable_set_callback(int val)
+{
+ if (val >= 0)
+ unregister_ipcns_notifier(current->nsproxy->ipc_ns);
+ else {
+ /*
+ * Re-enable automatic recomputing only if not already
+ * enabled.
+ */
+ recompute_msgmni(current->nsproxy->ipc_ns);
+ cond_register_ipcns_notifier(current->nsproxy->ipc_ns);
+ }
+}
+
#ifdef CONFIG_PROC_FS
static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
@@ -38,17 +61,17 @@ static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
static int proc_ipc_callback_dointvec(ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
{
+ struct ctl_table ipc_table;
size_t lenp_bef = *lenp;
int rc;
- rc = proc_ipc_dointvec(table, write, filp, buffer, lenp, ppos);
+ memcpy(&ipc_table, table, sizeof(ipc_table));
+ ipc_table.data = get_ipc(table);
+
+ rc = proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
if (write && !rc && lenp_bef == *lenp)
- /*
- * Tunable has successfully been changed from userland:
- * disable its automatic recomputing.
- */
- unregister_ipcns_notifier(current->nsproxy->ipc_ns);
+ tunable_set_callback(*((int *)(ipc_table.data)));
return rc;
}
@@ -119,12 +142,14 @@ static int sysctl_ipc_registered_data(ctl_table *table, int __user *name,
rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval,
newlen);
- if (newval && newlen && rc > 0)
+ if (newval && newlen && rc > 0) {
/*
- * Tunable has successfully been changed from userland:
- * disable its automatic recomputing.
+ * Tunable has successfully been changed from userland
*/
- unregister_ipcns_notifier(current->nsproxy->ipc_ns);
+ int *data = get_ipc(table);
+
+ tunable_set_callback(*data);
+ }
return rc;
}
diff --git a/ipc/ipcns_notifier.c b/ipc/ipcns_notifier.c
index c7974609def..70ff09183f7 100644
--- a/ipc/ipcns_notifier.c
+++ b/ipc/ipcns_notifier.c
@@ -61,6 +61,15 @@ int register_ipcns_notifier(struct ipc_namespace *ns)
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,