kmemtrace, fs, security: move alloc_secdata() and free_secdata() to linux/security.h

Impact: cleanup

We want to remove percpu.h from rcupdate.h (for upcoming kmemtrace
changes), but this is not possible currently without breaking the
build because fs.h has implicit include file depedencies: it uses
GFP_* types in inlines but does not include gfp.h.

In practice most fs.h using .c files get gfp.h included implicitly,
via an indirect route: via rcupdate.h inclusion - so this underlying
problem gets masked in practice.

So we want to solve fs.h's dependency on gfp.h.

gfp.h can not be included here directly because it is not exported and it
would break the build the following way:

  /home/mingo/tip/usr/include/linux/bsg.h:11: found __[us]{8,16,32,64} type without #include <linux/types.h>
  /home/mingo/tip/usr/include/linux/fs.h:11: included file 'linux/gfp.h' is not exported
  make[3]: *** [/home/mingo/tip/usr/include/linux/.check] Error 1
  make[2]: *** [linux] Error 2

As suggested by Alexey Dobriyan, move alloc_secdata() and free_secdata()
to linux/security.h - they belong there. This also cleans fs.h of GFP_*
usage.
Suggested-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
LKML-Reference: <1237906803.25315.96.camel@penberg-laptop>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/linux/fs.h

@@ -2382,27 +2382,6 @@ ssize_t simple_attr_read(struct file *file, char __user *buf,
 ssize_t simple_attr_write(struct file *file, const char __user *buf,
 			  size_t len, loff_t *ppos);
 
-
-#ifdef CONFIG_SECURITY
-static inline char *alloc_secdata(void)
-{
-	return (char *)get_zeroed_page(GFP_KERNEL);
-}
-
-static inline void free_secdata(void *secdata)
-{
-	free_page((unsigned long)secdata);
-}
-#else
-static inline char *alloc_secdata(void)
-{
-	return (char *)1;
-}
-
-static inline void free_secdata(void *secdata)
-{ }
-#endif	/* CONFIG_SECURITY */
-
 struct ctl_table;
 int proc_nr_files(struct ctl_table *table, int write, struct file *filp,
 		  void __user *buffer, size_t *lenp, loff_t *ppos);

include/linux/security.h

@@ -32,6 +32,7 @@
 #include <linux/sched.h>
 #include <linux/key.h>
 #include <linux/xfrm.h>
+#include <linux/gfp.h>
 #include <net/flow.h>
 
 /* Maximum number of letters for an LSM name string */
@@ -2953,5 +2954,28 @@ static inline void securityfs_remove(struct dentry *dentry)
 
 #endif
 
+#ifdef CONFIG_SECURITY
+
+static inline char *alloc_secdata(void)
+{
+	return (char *)get_zeroed_page(GFP_KERNEL);
+}
+
+static inline void free_secdata(void *secdata)
+{
+	free_page((unsigned long)secdata);
+}
+
+#else
+
+static inline char *alloc_secdata(void)
+{
+        return (char *)1;
+}
+
+static inline void free_secdata(void *secdata)
+{ }
+#endif /* CONFIG_SECURITY */
+
 #endif /* ! __LINUX_SECURITY_H */