From ab171b952c6e065779687b44041038efdadb3915 Mon Sep 17 00:00:00 2001
From: Luis Chamberlain <mcgrof@kernel.org>
Date: Fri, 21 Jan 2022 22:13:27 -0800
Subject: fs: move namespace sysctls and declare fs base directory

This moves the namespace sysctls to its own file as part of the
kernel/sysctl.c spring cleaning

Since we have now removed all sysctls for "fs", we now have to declare
it on the filesystem code, we do that using the new helper, which
reduces boiler plate code.

We rename init_fs_shared_sysctls() to init_fs_sysctls() to reflect that
now fs/sysctls.c is taking on the burden of being the first to register
the base directory as well.

Lastly, since init code will load in the order in which we link it we
have to move the sysctl code to be linked in early, so that its early
init routine runs prior to other fs code.  This way, other filesystem
code can register their own sysctls using the helpers after this:

  * register_sysctl_init()
  * register_sysctl()

Link: https://lkml.kernel.org/r/20211129211943.640266-3-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/namespace.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

(limited to 'fs/namespace.c')

diff --git a/fs/namespace.c b/fs/namespace.c
index dc31ad6b370f..40b994a29e90 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -37,7 +37,7 @@
 #include "internal.h"
 
 /* Maximum number of mounts in a mount namespace */
-unsigned int sysctl_mount_max __read_mostly = 100000;
+static unsigned int sysctl_mount_max __read_mostly = 100000;
 
 static unsigned int m_hash_mask __read_mostly;
 static unsigned int m_hash_shift __read_mostly;
@@ -4620,3 +4620,25 @@ const struct proc_ns_operations mntns_operations = {
 	.install	= mntns_install,
 	.owner		= mntns_owner,
 };
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table fs_namespace_sysctls[] = {
+	{
+		.procname	= "mount-max",
+		.data		= &sysctl_mount_max,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ONE,
+	},
+	{ }
+};
+
+static int __init init_fs_namespace_sysctls(void)
+{
+	register_sysctl_init("fs", fs_namespace_sysctls);
+	return 0;
+}
+fs_initcall(init_fs_namespace_sysctls);
+
+#endif /* CONFIG_SYSCTL */
-- 
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