fs: move fs stat sysctls to file_table.c

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.

We can create the sysctl dynamically on early init for fs stat to help
with this clutter.  This dusts off the fs stat syctls knobs and puts
them into where they are declared.

Link: https://lkml.kernel.org/r/20211129205548.605569-3-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
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>

1 files changed, 39 insertions, 8 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 45437f8e1003..57edef16dce4 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -33,7 +33,7 @@
 #include "internal.h"
 
 /* sysctl tunables... */
-struct files_stat_struct files_stat = {
+static struct files_stat_struct files_stat = {
 	.max_files = NR_FILE
 };
 
@@ -75,22 +75,53 @@ unsigned long get_max_files(void)
 }
 EXPORT_SYMBOL_GPL(get_max_files);
 
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+
 /*
  * Handle nr_files sysctl
  */
-#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
-int proc_nr_files(struct ctl_table *table, int write,
-                     void *buffer, size_t *lenp, loff_t *ppos)
+static int proc_nr_files(struct ctl_table *table, int write, void *buffer,
+			 size_t *lenp, loff_t *ppos)
 {
 	files_stat.nr_files = get_nr_files();
 	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 }
-#else
-int proc_nr_files(struct ctl_table *table, int write,
-                     void *buffer, size_t *lenp, loff_t *ppos)
+
+static struct ctl_table fs_stat_sysctls[] = {
+	{
+		.procname	= "file-nr",
+		.data		= &files_stat,
+		.maxlen		= sizeof(files_stat),
+		.mode		= 0444,
+		.proc_handler	= proc_nr_files,
+	},
+	{
+		.procname	= "file-max",
+		.data		= &files_stat.max_files,
+		.maxlen		= sizeof(files_stat.max_files),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+		.extra1		= SYSCTL_LONG_ZERO,
+		.extra2		= SYSCTL_LONG_MAX,
+	},
+	{
+		.procname	= "nr_open",
+		.data		= &sysctl_nr_open,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &sysctl_nr_open_min,
+		.extra2		= &sysctl_nr_open_max,
+	},
+	{ }
+};
+
+static int __init init_fs_stat_sysctls(void)
 {
-	return -ENOSYS;
+	register_sysctl_init("fs", fs_stat_sysctls);
+	return 0;
 }
+fs_initcall(init_fs_stat_sysctls);
 #endif
 
 static struct file *__alloc_file(int flags, const struct cred *cred)