[PATCH v2 8/8] sysctl: share unsigned long const values

Luis Chamberlain
2021-11-24T23:15:23Z

Provide a way to share unsigned long values.
This will allow others to not have to re-invent
these values.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
fs/proc/proc_sysctl.c | 3 +++
include/linux/sysctl.h | 6 ++++++
kernel/sysctl.c | 9 +++------
3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index aa743bbb8400..2b73648a19a5 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -29,6 +29,9 @@ static const struct inode_operations proc_sys_dir_operations;
const int sysctl_vals[] = { -1, 0, 1, 2, 4, 100, 200, 1000, INT_MAX };
EXPORT_SYMBOL(sysctl_vals);

+const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX };
+EXPORT_SYMBOL_GPL(sysctl_long_vals);
+
/* Support for permanently empty directories */

struct ctl_table sysctl_mount_point[] = {
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 7946b532e964..162aaee92daf 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -50,6 +50,12 @@ struct ctl_dir;

extern const int sysctl_vals[];

+#define SYSCTL_LONG_ZERO ((void *)&sysctl_long_vals[0])
+#define SYSCTL_LONG_ONE ((void *)&sysctl_long_vals[1])
+#define SYSCTL_LONG_MAX ((void *)&sysctl_long_vals[2])
+
+extern const unsigned long sysctl_long_vals[];
+
typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
size_t *lenp, loff_t *ppos);

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5812d76ecee1..b8a3dcf7b925 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -99,9 +99,6 @@

/* Constants used for minimum and maximum */

-static const unsigned long zero_ul;
-static const unsigned long one_ul = 1;
-static const unsigned long long_max = LONG_MAX;
#ifdef CONFIG_PRINTK
static const int ten_thousand = 10000;
#endif
@@ -2512,7 +2509,7 @@ static struct ctl_table vm_table[] = {
.maxlen = sizeof(dirty_background_bytes),
.mode = 0644,
.proc_handler = dirty_background_bytes_handler,
- .extra1 = (void *)&one_ul,
+ .extra1 = SYSCTL_LONG_ONE,
},
{
.procname = "dirty_ratio",
@@ -2930,8 +2927,8 @@ static struct ctl_table fs_table[] = {
.maxlen = sizeof(files_stat.max_files),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
- .extra1 = (void *)&zero_ul,
- .extra2 = (void *)&long_max,
+ .extra1 = SYSCTL_LONG_ZERO,
+ .extra2 = SYSCTL_LONG_MAX,
},
{
.procname = "nr_open",
--
2.33.0