[PATCH v2 -next 06/15] mm: mmap: move sysctl into its own file

[Kaixiong Yu <yukaixiong@xxxxxxxxxx>]

This moves all mmap related sysctls to its own file, as part of the
kernel/sysctl.c cleaning, also move the variable declaration from
kernel/sysctl.c into mm/mmap.c.

Signed-off-by: Kaixiong Yu <yukaixiong@xxxxxxxxxx>
Reviewed-by: Kees Cook <kees@xxxxxxxxxx>
---
v2:
 - fix sysctl_max_map_count undeclared issue in mm/nommu.c
---
 kernel/sysctl.c | 50 +--------------------------------------------
 mm/mmap.c       | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 49 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ad3ac6f6c808..41d4afc978e6 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -127,12 +127,6 @@ enum sysctl_writes_mode {
 
 static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
 #endif /* CONFIG_PROC_SYSCTL */
-
-#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
-    defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
-int sysctl_legacy_va_layout;
-#endif
-
 #endif /* CONFIG_SYSCTL */
 
 /*
@@ -2047,16 +2041,7 @@ static struct ctl_table vm_table[] = {
 		.extra1		= SYSCTL_ONE,
 		.extra2		= SYSCTL_FOUR,
 	},
-#ifdef CONFIG_MMU
-	{
-		.procname	= "max_map_count",
-		.data		= &sysctl_max_map_count,
-		.maxlen		= sizeof(sysctl_max_map_count),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-	},
-#else
+#ifndef CONFIG_MMU
 	{
 		.procname	= "nr_trim_pages",
 		.data		= &sysctl_nr_trim_pages,
@@ -2074,17 +2059,6 @@ static struct ctl_table vm_table[] = {
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
 	},
-#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
-    defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
-	{
-		.procname	= "legacy_va_layout",
-		.data		= &sysctl_legacy_va_layout,
-		.maxlen		= sizeof(sysctl_legacy_va_layout),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-	},
-#endif
 #ifdef CONFIG_MMU
 	{
 		.procname	= "mmap_min_addr",
@@ -2110,28 +2084,6 @@ static struct ctl_table vm_table[] = {
 		.extra1		= SYSCTL_ZERO,
 	},
 #endif
-#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
-	{
-		.procname	= "mmap_rnd_bits",
-		.data		= &mmap_rnd_bits,
-		.maxlen		= sizeof(mmap_rnd_bits),
-		.mode		= 0600,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&mmap_rnd_bits_min,
-		.extra2		= (void *)&mmap_rnd_bits_max,
-	},
-#endif
-#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
-	{
-		.procname	= "mmap_rnd_compat_bits",
-		.data		= &mmap_rnd_compat_bits,
-		.maxlen		= sizeof(mmap_rnd_compat_bits),
-		.mode		= 0600,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&mmap_rnd_compat_bits_min,
-		.extra2		= (void *)&mmap_rnd_compat_bits_max,
-	},
-#endif
 };
 
 int __init sysctl_init_bases(void)
diff --git a/mm/mmap.c b/mm/mmap.c
index c018f5a5bffd..e3d888aa1e25 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2120,6 +2120,57 @@ struct vm_area_struct *_install_special_mapping(
 					&special_mapping_vmops);
 }
 
+#ifdef CONFIG_SYSCTL
+#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
+		defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
+int sysctl_legacy_va_layout;
+#endif
+
+static struct ctl_table mmap_table[] = {
+		{
+				.procname       = "max_map_count",
+				.data           = &sysctl_max_map_count,
+				.maxlen         = sizeof(sysctl_max_map_count),
+				.mode           = 0644,
+				.proc_handler   = proc_dointvec_minmax,
+				.extra1         = SYSCTL_ZERO,
+		},
+#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
+		defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
+		{
+				.procname       = "legacy_va_layout",
+				.data           = &sysctl_legacy_va_layout,
+				.maxlen         = sizeof(sysctl_legacy_va_layout),
+				.mode           = 0644,
+				.proc_handler   = proc_dointvec_minmax,
+				.extra1         = SYSCTL_ZERO,
+		},
+#endif
+#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
+		{
+				.procname       = "mmap_rnd_bits",
+				.data           = &mmap_rnd_bits,
+				.maxlen         = sizeof(mmap_rnd_bits),
+				.mode           = 0600,
+				.proc_handler   = proc_dointvec_minmax,
+				.extra1         = (void *)&mmap_rnd_bits_min,
+				.extra2         = (void *)&mmap_rnd_bits_max,
+		},
+#endif
+#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
+		{
+				.procname       = "mmap_rnd_compat_bits",
+				.data           = &mmap_rnd_compat_bits,
+				.maxlen         = sizeof(mmap_rnd_compat_bits),
+				.mode           = 0600,
+				.proc_handler   = proc_dointvec_minmax,
+				.extra1         = (void *)&mmap_rnd_compat_bits_min,
+				.extra2         = (void *)&mmap_rnd_compat_bits_max,
+		},
+#endif
+};
+#endif /* CONFIG_SYSCTL */
+
 /*
  * initialise the percpu counter for VM
  */
@@ -2129,6 +2180,9 @@ void __init mmap_init(void)
 
 	ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
 	VM_BUG_ON(ret);
+#ifdef CONFIG_SYSCTL
+	register_sysctl_init("vm", mmap_table);
+#endif
 }
 
 /*
-- 
2.25.1