[v2,2/4] sysctl: Move some boundary constants form sysctl.c to sysctl_vals

Commit Message

Nixiaoming May 16, 2020, 8:55 a.m. UTC

Some boundary (.extra1 .extra2) constants (E.g: neg_one two) in
sysctl.c are used in multiple features. Move these variables to
sysctl_vals to avoid adding duplicate variables when cleaning up
sysctls table.

Signed-off-by: Xiaoming Ni <[e-mail]>
---
 fs/proc/proc_sysctl.c  |  2 +-
 include/linux/sysctl.h | 11 ++++++++---
 kernel/sysctl.c        | 37 ++++++++++++++++---------------------
 3 files changed, 25 insertions(+), 25 deletions(-)

Comments

Kees Cook May 17, 2020, 2:40 a.m. UTC | #1

On Sat, May 16, 2020 at 04:55:13PM +0800, Xiaoming Ni wrote:
> Some boundary (.extra1 .extra2) constants (E.g: neg_one two) in
> sysctl.c are used in multiple features. Move these variables to
> sysctl_vals to avoid adding duplicate variables when cleaning up
> sysctls table.
> 
> Signed-off-by: Xiaoming Ni <[e-mail]>

Reviewed-by: Kees Cook <[e-mail]>

Patch

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b6f5d45..3f77e64 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -23,7 +23,7 @@ 
 static const struct inode_operations proc_sys_dir_operations;
 
 /* shared constants to be used in various sysctls */
-const int sysctl_vals[] = { 0, 1, INT_MAX };
+const int sysctl_vals[] = { -1, 0, 1, 2, 4, 100, 1000, INT_MAX };
 EXPORT_SYMBOL(sysctl_vals);
 
 /* Support for permanently empty directories */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 43f8ef9..bf97c30 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -38,9 +38,14 @@ 
 struct ctl_dir;
 
 /* Keep the same order as in fs/proc/proc_sysctl.c */
-#define SYSCTL_ZERO	((void *)&sysctl_vals[0])
-#define SYSCTL_ONE	((void *)&sysctl_vals[1])
-#define SYSCTL_INT_MAX	((void *)&sysctl_vals[2])
+#define SYSCTL_NEG_ONE	((void *)&sysctl_vals[0])
+#define SYSCTL_ZERO	((void *)&sysctl_vals[1])
+#define SYSCTL_ONE	((void *)&sysctl_vals[2])
+#define SYSCTL_TWO	((void *)&sysctl_vals[3])
+#define SYSCTL_FOUR	((void *)&sysctl_vals[4])
+#define SYSCTL_ONE_HUNDRED	((void *)&sysctl_vals[5])
+#define SYSCTL_ONE_THOUSAND	((void *)&sysctl_vals[6])
+#define SYSCTL_INT_MAX	((void *)&sysctl_vals[7])
 
 extern const int sysctl_vals[];
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 20c31f5..5f08cc2 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -124,14 +124,9 @@ 
 static int sixty = 60;
 #endif
 
-static int __maybe_unused neg_one = -1;
-static int __maybe_unused two = 2;
-static int __maybe_unused four = 4;
 static unsigned long zero_ul;
 static unsigned long one_ul = 1;
 static unsigned long long_max = LONG_MAX;
-static int one_hundred = 100;
-static int one_thousand = 1000;
 #ifdef CONFIG_PRINTK
 static int ten_thousand = 10000;
 #endif
@@ -547,7 +542,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &neg_one,
+		.extra1		= SYSCTL_NEG_ONE,
 		.extra2		= SYSCTL_ONE,
 	},
 #endif
@@ -878,7 +873,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax_sysadmin,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
 	},
 #endif
 	{
@@ -1189,7 +1184,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= perf_cpu_time_max_percent_handler,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 	{
 		.procname	= "perf_event_max_stack",
@@ -1207,7 +1202,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= perf_event_max_stack_handler,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_thousand,
+		.extra2		= SYSCTL_ONE_THOUSAND,
 	},
 #endif
 	{
@@ -1282,7 +1277,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
 	},
 	{
 		.procname	= "panic_on_oom",
@@ -1291,7 +1286,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
 	},
 	{
 		.procname	= "oom_kill_allocating_task",
@@ -1336,7 +1331,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= dirty_background_ratio_handler,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 	{
 		.procname	= "dirty_background_bytes",
@@ -1353,7 +1348,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= dirty_ratio_handler,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 	{
 		.procname	= "dirty_bytes",
@@ -1393,7 +1388,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 #ifdef CONFIG_HUGETLB_PAGE
 	{
@@ -1450,7 +1445,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0200,
 		.proc_handler	= drop_caches_sysctl_handler,
 		.extra1		= SYSCTL_ONE,
-		.extra2		= &four,
+		.extra2		= SYSCTL_FOUR,
 	},
 #ifdef CONFIG_COMPACTION
 	{
@@ -1503,7 +1498,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= watermark_scale_factor_sysctl_handler,
 		.extra1		= SYSCTL_ONE,
-		.extra2		= &one_thousand,
+		.extra2		= SYSCTL_ONE_THOUSAND,
 	},
 	{
 		.procname	= "percpu_pagelist_fraction",
@@ -1582,7 +1577,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 	{
 		.procname	= "min_slab_ratio",
@@ -1591,7 +1586,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 #endif
 #ifdef CONFIG_SMP
@@ -1874,7 +1869,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
 	},
 	{
 		.procname	= "protected_regular",
@@ -1883,7 +1878,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
 	},
 	{
 		.procname	= "suid_dumpable",
@@ -1892,7 +1887,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax_coredump,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
 	},
 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
 	{