[patch 3/4] make pr_debug() dynamic - sysctl support

[Jason Baron <jbaron@redhat.com>]

-add /proc/sys/debug/pr_debug, to toggle pr_debug() on/off

Signed-off-by: Jason Baron <jbaron@redhat.com>
---

 kernel/sysctl.c |   41 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 41 insertions(+), 0 deletions(-)


diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 7cb1ac3..73508d7 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -155,6 +155,11 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp
 static int proc_dointvec_taint(struct ctl_table *table, int write, struct file *filp,
 			       void __user *buffer, size_t *lenp, loff_t *ppos);
 #endif
+#ifdef CONFIG_PR_DEBUG_DYNAMIC
+static int proc_pr_debug_handler(struct ctl_table *table, int write,
+				 struct file *filp, void __user *buffer,
+				 size_t *lenp, loff_t *ppos);
+#endif
 
 static struct ctl_table root_table[];
 static struct ctl_table_root sysctl_table_root;
@@ -1312,6 +1317,16 @@ static struct ctl_table debug_table[] = {
 		.proc_handler	= proc_dointvec
 	},
 #endif
+#ifdef CONFIG_PR_DEBUG_DYNAMIC
+	{
+		.ctl_name       = CTL_UNNUMBERED,
+		.procname       = "pr_debug",
+		.data           = NULL,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = &proc_pr_debug_handler
+	},
+#endif
 	{ .ctl_name = 0 }
 };
 
@@ -2499,6 +2514,32 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp
 	return 0;
 }
 
+#ifdef CONFIG_PR_DEBUG_DYNAMIC
+
+static int proc_pr_debug_handler(struct ctl_table *table, int write,
+				 struct file *filp, void __user *buffer,
+				 size_t *lenp, loff_t *ppos)
+{
+	int tmp, r;
+
+	if (!write)
+		tmp = imv_read(pr_debug_on);
+	r = __do_proc_dointvec(&tmp, table, write, filp, buffer,
+				lenp, ppos, NULL, NULL);
+	if (r)
+		return r;
+
+	if (write) {
+		if (tmp)
+			imv_set(pr_debug_on, 1);
+		else
+			imv_set(pr_debug_on, 0);
+	}
+	return 0;
+}
+
+#endif
+
 #else /* CONFIG_PROC_FS */
 
 int proc_dostring(struct ctl_table *table, int write, struct file *filp,