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>

diff --git a/fs/dcache.c b/fs/dcache.c
index cf871a81f4fdcc5501463c3c3a35e4aac3c03eec..c84269c6e8bf6df3b9e53ed42bb450bd500e2afe 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -115,10 +115,13 @@ static inline struct hlist_bl_head *in_lookup_hash(const struct dentry *parent,
        return in_lookup_hashtable + hash_32(hash, IN_LOOKUP_SHIFT);
 }
 
-
-/* Statistics gathering. */
-struct dentry_stat_t dentry_stat = {
-       .age_limit = 45,
+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 */
 };
 
 static DEFINE_PER_CPU(long, nr_dentry);
@@ -126,6 +129,10 @@ static DEFINE_PER_CPU(long, nr_dentry_unused);
 static DEFINE_PER_CPU(long, nr_dentry_negative);
 
 #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+/* Statistics gathering. */
+static struct dentry_stat_t dentry_stat = {
+       .age_limit = 45,
+};
 
 /*
  * Here we resort to our own counters instead of using generic per-cpu counters
@@ -167,14 +174,32 @@ static long get_nr_dentry_negative(void)
        return sum < 0 ? 0 : sum;
 }
 
-int proc_nr_dentry(struct ctl_table *table, int write, void *buffer,
-                  size_t *lenp, loff_t *ppos)
+static int proc_nr_dentry(struct ctl_table *table, int write, void *buffer,
+                         size_t *lenp, loff_t *ppos)
 {
        dentry_stat.nr_dentry = get_nr_dentry();
        dentry_stat.nr_unused = get_nr_dentry_unused();
        dentry_stat.nr_negative = get_nr_dentry_negative();
        return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 }
+
+static struct ctl_table fs_dcache_sysctls[] = {
+       {
+               .procname       = "dentry-state",
+               .data           = &dentry_stat,
+               .maxlen         = 6*sizeof(long),
+               .mode           = 0444,
+               .proc_handler   = proc_nr_dentry,
+       },
+       { }
+};
+
+static int __init init_fs_dcache_sysctls(void)
+{
+       register_sysctl_init("fs", fs_dcache_sysctls);
+       return 0;
+}
+fs_initcall(init_fs_dcache_sysctls);
 #endif
 
 /*

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 9e23d33bb6f1c853d7c22aa03d6bcd9b3c823cd2..f5bba51480b2f720b45fda36567e0dc8b30b0f24 100644 (file)
--- 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

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1e676196612030a2dcf591fb9901e3c111c3ffff..9b856d5da9e2689d953ab8aedd5ebe1394df6787 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3531,8 +3531,6 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
                          size_t len, loff_t *ppos);
 
 struct ctl_table;
-int proc_nr_dentry(struct ctl_table *table, int write,
-                 void *buffer, size_t *lenp, loff_t *ppos);
 int __init list_bdev_fs_names(char *buf, size_t size);
 
 #define __FMODE_EXEC           ((__force int) FMODE_EXEC)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d2c411b158540590590d865193eb16c312ee6008..4d182fb5c22e48141b3497997cc98982ee2fc4ca 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2901,13 +2901,6 @@ static struct ctl_table vm_table[] = {
 };
 
 static struct ctl_table fs_table[] = {
-       {
-               .procname       = "dentry-state",
-               .data           = &dentry_stat,
-               .maxlen         = 6*sizeof(long),
-               .mode           = 0444,
-               .proc_handler   = proc_nr_dentry,
-       },
        {
                .procname       = "overflowuid",
                .data           = &fs_overflowuid,