fs: move dcache sysctls to its own file

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 dcache sysctl clutter out of kernel/sysctl.c.  This is a
small one-off entry, perhaps later we can simplify this representation,
but for now we use the helpers we have.  We won't know how we can
simplify this further untl we're fully done with the cleanup.

[arnd@arndb.de: avoid unused-function warning]
  Link: https://lkml.kernel.org/r/20211203190123.874239-2-arnd@kernel.org

Link: https://lkml.kernel.org/r/20211129205548.605569-4-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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, 0 insertions, 10 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 9e23d33bb6f1..f5bba51480b2 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -61,16 +61,6 @@ extern const struct qstr empty_name;
 extern const struct qstr slash_name;
 extern const struct qstr dotdot_name;
 
-struct dentry_stat_t {
-	long nr_dentry;
-	long nr_unused;
-	long age_limit;		/* age in seconds */
-	long want_pages;	/* pages requested by system */
-	long nr_negative;	/* # of unused negative dentries */
-	long dummy;		/* Reserved for future use */
-};
-extern struct dentry_stat_t dentry_stat;
-
 /*
  * Try to keep struct dentry aligned on 64 byte cachelines (this will
  * give reasonable cacheline footprint with larger lines without the