[PATCH 10/13] eventpoll: simplify sysctl declaration with register_sysctl_subdir()

From: Luis Chamberlain
Date: Fri May 29 2020 - 03:41:41 EST


From: Xiaoming Ni <nixiaoming@xxxxxxxxxx>

Move epoll_table sysctl to fs/eventpoll.c and remove the
clutter out of kernel/sysctl.c by using register_sysctl_subdir()..

Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
fs/eventpoll.c | 10 +++++++++-
include/linux/poll.h | 2 --
include/linux/sysctl.h | 1 -
kernel/sysctl.c | 7 -------
4 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 12eebcdea9c8..957ebc9700e3 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -299,7 +299,7 @@ static LIST_HEAD(tfile_check_list);
static long long_zero;
static long long_max = LONG_MAX;

-struct ctl_table epoll_table[] = {
+static struct ctl_table epoll_table[] = {
{
.procname = "max_user_watches",
.data = &max_user_watches,
@@ -311,6 +311,13 @@ struct ctl_table epoll_table[] = {
},
{ }
};
+
+static void __init epoll_sysctls_init(void)
+{
+ register_sysctl_subdir("fs", "epoll", epoll_table);
+}
+#else
+#define epoll_sysctls_init() do { } while (0)
#endif /* CONFIG_SYSCTL */

static const struct file_operations eventpoll_fops;
@@ -2422,6 +2429,7 @@ static int __init eventpoll_init(void)
/* Allocates slab cache used to allocate "struct eppoll_entry" */
pwq_cache = kmem_cache_create("eventpoll_pwq",
sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL);
+ epoll_sysctls_init();

return 0;
}
diff --git a/include/linux/poll.h b/include/linux/poll.h
index 1cdc32b1f1b0..a9e0e1c2d1f2 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -8,12 +8,10 @@
#include <linux/wait.h>
#include <linux/string.h>
#include <linux/fs.h>
-#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <uapi/linux/poll.h>
#include <uapi/linux/eventpoll.h>

-extern struct ctl_table epoll_table[]; /* for sysctl */
/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
additional memory. */
#ifdef __clang__
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index aa01f54d0442..e5364b69dd95 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -217,7 +217,6 @@ extern int no_unaligned_warning;

extern struct ctl_table sysctl_mount_point[];
extern struct ctl_table random_table[];
-extern struct ctl_table epoll_table[];

#else /* CONFIG_SYSCTL */
static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e007375c8a11..5c116904feb7 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3001,13 +3001,6 @@ static struct ctl_table fs_table[] = {
.proc_handler = proc_dointvec,
},
#endif
-#ifdef CONFIG_EPOLL
- {
- .procname = "epoll",
- .mode = 0555,
- .child = epoll_table,
- },
-#endif
#endif
{
.procname = "protected_symlinks",
--
2.26.2