Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6

[pandora-kernel.git] / ipc / ipc_sysctl.c

diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index d12ff5c..d349746 100644 (file)
--- 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;
 }