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
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: 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: 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>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 06f4c5ae1451eff56e0e4f47ca90926af110155a..e2daa940ebce7c77ee836aca2a6e82a7deb80b18 100644 (file)
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -307,7 +307,7 @@ static void unlist_file(struct epitems_head *head)
 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);

diff --git a/include/linux/poll.h b/include/linux/poll.h
index 1cdc32b1f1b0836e6dccf2ecf446b9aeab0a950b..a9e0e1c2d1f2ff89d99a9377a1de7d0dc78483cd 100644 (file)
--- 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 47cf70c8eb93c8b3d22f21c37355e2e435faaae5..6dd0f277f8443ba207f63d36403bf399800893f4 100644 (file)
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -219,7 +219,6 @@ 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)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 2ee0e76888d8a11600500fa1966ab7360dc12468..09fa72299f188646b80bc8f1083ce7ceedbcdd7e 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3093,13 +3093,6 @@ 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",