Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux...

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

diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 7f4235b..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)
@@ -35,6 +58,24 @@ static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
        return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
 }
 
+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;
+
+       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_set_callback(*((int *)(ipc_table.data)));
+
+       return rc;
+}
+
 static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
        struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -49,6 +90,7 @@ static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
 #else
 #define proc_ipc_doulongvec_minmax NULL
 #define proc_ipc_dointvec         NULL
+#define proc_ipc_callback_dointvec NULL
 #endif
 
 #ifdef CONFIG_SYSCTL_SYSCALL
@@ -90,8 +132,30 @@ static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen,
        }
        return 1;
 }
+
+static int sysctl_ipc_registered_data(ctl_table *table, int __user *name,
+               int nlen, void __user *oldval, size_t __user *oldlenp,
+               void __user *newval, size_t newlen)
+{
+       int rc;
+
+       rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval,
+               newlen);
+
+       if (newval && newlen && rc > 0) {
+               /*
+                * Tunable has successfully been changed from userland
+                */
+               int *data = get_ipc(table);
+
+               tunable_set_callback(*data);
+       }
+
+       return rc;
+}
 #else
 #define sysctl_ipc_data NULL
+#define sysctl_ipc_registered_data NULL
 #endif
 
 static struct ctl_table ipc_kern_table[] = {
@@ -137,8 +201,8 @@ static struct ctl_table ipc_kern_table[] = {
                .data           = &init_ipc_ns.msg_ctlmni,
                .maxlen         = sizeof (init_ipc_ns.msg_ctlmni),
                .mode           = 0644,
-               .proc_handler   = proc_ipc_dointvec,
-               .strategy       = sysctl_ipc_data,
+               .proc_handler   = proc_ipc_callback_dointvec,
+               .strategy       = sysctl_ipc_registered_data,
        },
        {
                .ctl_name       = KERN_MSGMNB,