Input: sysrq: mv sysrq into drivers/tty/sysrq.c

Move both sysrq ctl_table and supported sysrq_sysctl_handler helper
function into drivers/tty/sysrq.c. Replaced the __do_proc_dointvec in
helper function with do_proc_dointvec_minmax as the former is local to
kernel/sysctl.c. Here we use the minmax version of do_proc_dointvec
because do_proc_dointvec is static and calling do_proc_dointvec_minmax
with a NULL min and max is the same as calling do_proc_dointvec.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kernel/sysctl.c.

Reviewed-by: Kees Cook <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

Author: Joelgranados

drivers/tty/sysrq.c

@@ -1120,6 +1120,47 @@ int sysrq_toggle_support(int enable_mask)
 }
 EXPORT_SYMBOL_GPL(sysrq_toggle_support);
 
+static int sysrq_sysctl_handler(const struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int tmp, ret;
+	struct ctl_table t = *table;
+
+	tmp = sysrq_mask();
+	t.data = &tmp;
+
+	/*
+	 * Behaves like do_proc_dointvec as t does not have min nor max.
+	 */
+	ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+
+	if (ret || !write)
+		return ret;
+
+	if (write)
+		sysrq_toggle_support(tmp);
+
+	return 0;
+}
+
+static const struct ctl_table sysrq_sysctl_table[] = {
+	{
+		.procname	= "sysrq",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= sysrq_sysctl_handler,
+	},
+};
+
+static int __init init_sysrq_sysctl(void)
+{
+	register_sysctl_init("kernel", sysrq_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_sysrq_sysctl);
+
 static int __sysrq_swap_key_ops(u8 key, const struct sysrq_key_op *insert_op_p,
 				const struct sysrq_key_op *remove_op_p)
 {

kernel/sysctl.c

@@ -31,7 +31,6 @@
 #include <linux/kernel.h>
 #include <linux/kobject.h>
 #include <linux/net.h>
-#include <linux/sysrq.h>
 #include <linux/highuid.h>
 #include <linux/writeback.h>
 #include <linux/ratelimit.h>
@@ -964,26 +963,6 @@ int proc_dou8vec_minmax(const struct ctl_table *table, int write,
 }
 EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
 
-#ifdef CONFIG_MAGIC_SYSRQ
-static int sysrq_sysctl_handler(const struct ctl_table *table, int write,
-				void *buffer, size_t *lenp, loff_t *ppos)
-{
-	int tmp, ret;
-
-	tmp = sysrq_mask();
-
-	ret = __do_proc_dointvec(&tmp, table, write, buffer,
-			       lenp, ppos, NULL, NULL);
-	if (ret || !write)
-		return ret;
-
-	if (write)
-		sysrq_toggle_support(tmp);
-
-	return 0;
-}
-#endif
-
 static int __do_proc_doulongvec_minmax(void *data,
 		const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos,
@@ -1612,15 +1591,6 @@ static const struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dostring,
 	},
 #endif
-#ifdef CONFIG_MAGIC_SYSRQ
-	{
-		.procname	= "sysrq",
-		.data		= NULL,
-		.maxlen		= sizeof (int),
-		.mode		= 0644,
-		.proc_handler	= sysrq_sysctl_handler,
-	},
-#endif
 #ifdef CONFIG_PROC_SYSCTL
 	{
 		.procname	= "cad_pid",