fs: dcache: move the sysctl to fs/dcache.c

The sysctl_vfs_cache_pressure belongs to fs/dcache.c, move it to
fs/dcache.c from kernel/sysctl.c. As a part of fs/dcache.c cleaning,
sysctl_vfs_cache_pressure is changed to a static variable, and change
the inline-type function vfs_pressure_ratio() to out-of-inline type,
export vfs_pressure_ratio() with EXPORT_SYMBOL_GPL to be used by other
files. Move the unneeded include(linux/dcache.h).

Signed-off-by: Kaixiong Yu <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Christian Brauner <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

Author: yukaixiong

fs/dcache.c

@@ -73,8 +73,13 @@
  * If no ancestor relationship:
  * arbitrary, since it's serialized on rename_lock
  */
-int sysctl_vfs_cache_pressure __read_mostly = 100;
-EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
+static int sysctl_vfs_cache_pressure __read_mostly = 100;
+
+unsigned long vfs_pressure_ratio(unsigned long val)
+{
+	return mult_frac(val, sysctl_vfs_cache_pressure, 100);
+}
+EXPORT_SYMBOL_GPL(vfs_pressure_ratio);
 
 __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
 
@@ -211,8 +216,20 @@ static const struct ctl_table fs_dcache_sysctls[] = {
 	},
 };
 
+static const struct ctl_table vm_dcache_sysctls[] = {
+	{
+		.procname	= "vfs_cache_pressure",
+		.data		= &sysctl_vfs_cache_pressure,
+		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+};
+
 static int __init init_fs_dcache_sysctls(void)
 {
+	register_sysctl_init("vm", vm_dcache_sysctls);
 	register_sysctl_init("fs", fs_dcache_sysctls);
 	return 0;
 }

include/linux/dcache.h

@@ -520,12 +520,7 @@ static inline int simple_positive(const struct dentry *dentry)
 	return d_really_is_positive(dentry) && !d_unhashed(dentry);
 }
 
-extern int sysctl_vfs_cache_pressure;
-
-static inline unsigned long vfs_pressure_ratio(unsigned long val)
-{
-	return mult_frac(val, sysctl_vfs_cache_pressure, 100);
-}
+unsigned long vfs_pressure_ratio(unsigned long val);
 
 /**
  * d_inode - Get the actual inode of this dentry

kernel/sysctl.c

@@ -46,7 +46,6 @@
 #include <linux/key.h>
 #include <linux/times.h>
 #include <linux/limits.h>
-#include <linux/dcache.h>
 #include <linux/syscalls.h>
 #include <linux/nfs_fs.h>
 #include <linux/acpi.h>
@@ -2014,14 +2013,6 @@ static const struct ctl_table kern_table[] = {
 };
 
 static const struct ctl_table vm_table[] = {
-	{
-		.procname	= "vfs_cache_pressure",
-		.data		= &sysctl_vfs_cache_pressure,
-		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-	},
 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
 	{