+ eventpoll-simplify-sysctl-declaration-with-register_sysctl.patch added to -mm tree

+ eventpoll-simplify-sysctl-declaration-with-register_sysctl.patch added to -mm tree

[akpm]

The patch titled
     Subject: eventpoll: simplify sysctl declaration with register_sysctl()
has been added to the -mm tree.  Its filename is
     eventpoll-simplify-sysctl-declaration-with-register_sysctl.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/eventpoll-simplify-sysctl-declaration-with-register_sysctl.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/eventpoll-simplify-sysctl-declaration-with-register_sysctl.patch

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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there every 3-4 working days

------------------------------------------------------
From: Xiaoming Ni <nixiaoming@huawei.com>
Subject: eventpoll: simplify sysctl declaration with register_sysctl()

The kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we just
care about the core logic.

So move the epoll_table sysctl to fs/eventpoll.c and use use
register_sysctl().

Link: https://lkml.kernel.org/r/20211123202422.819032-9-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hailong Liu <liu.hailong6@zte.com.cn>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Qing Wang <wangqing@vivo.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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(-)

--- a/fs/eventpoll.c~eventpoll-simplify-sysctl-declaration-with-register_sysctl
+++ a/fs/eventpoll.c
@@ -307,7 +307,7 @@ static void unlist_file(struct epitems_h
 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,
@@ -319,6 +319,13 @@ struct ctl_table epoll_table[] = {
 	},
 	{ }
 };
+
+static void __init epoll_sysctls_init(void)
+{
+	register_sysctl("fs/epoll", epoll_table);
+}
+#else
+#define epoll_sysctls_init() do { } while (0)
 #endif /* CONFIG_SYSCTL */
 
 static const struct file_operations eventpoll_fops;
@@ -2378,6 +2385,7 @@ 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();
 
 	ephead_cache = kmem_cache_create("ep_head",
 		sizeof(struct epitems_head), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL);
--- a/include/linux/poll.h~eventpoll-simplify-sysctl-declaration-with-register_sysctl
+++ a/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__
--- a/include/linux/sysctl.h~eventpoll-simplify-sysctl-declaration-with-register_sysctl
+++ a/include/linux/sysctl.h
@@ -218,7 +218,6 @@ extern int no_unaligned_warning;
 extern struct ctl_table sysctl_mount_point[];
 extern struct ctl_table random_table[];
 extern struct ctl_table firmware_config_table[];
-extern struct ctl_table epoll_table[];
 
 #else /* CONFIG_SYSCTL */
 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
--- a/kernel/sysctl.c~eventpoll-simplify-sysctl-declaration-with-register_sysctl
+++ a/kernel/sysctl.c
@@ -3092,13 +3092,6 @@ 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",
_

Patches currently in -mm which might be from nixiaoming@huawei.com are

sysctl-add-a-new-register_sysctl_init-interface.patch
sysctl-move-some-boundary-constants-from-sysctlc-to-sysctl_vals.patch
hung_task-move-hung_task-sysctl-interface-to-hung_taskc.patch
watchdog-move-watchdog-sysctl-interface-to-watchdogc.patch
sysctl-use-const-for-typically-used-max-min-proc-sysctls.patch
sysctl-use-sysctl_zero-to-replace-some-static-int-zero-uses.patch
aio-move-aio-sysctl-to-aioc.patch
dnotify-move-dnotify-sysctl-to-dnotifyc.patch
inotify-simplify-subdirectory-registration-with-register_sysctl.patch
eventpoll-simplify-sysctl-declaration-with-register_sysctl.patch