mm: cleancache: clean up cleancache_enabled

cleancache_ops is used to decide whether backend is registered.
So now cleancache_enabled is always true if defined CONFIG_CLEANCACHE.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 1 insertions, 12 deletions

diff --git a/include/linux/cleancache.h b/include/linux/cleancache.h
index 3af5ea839558..4ce9056b31a8 100644
--- a/include/linux/cleancache.h
+++ b/include/linux/cleancache.h
@@ -42,9 +42,9 @@ extern void __cleancache_put_page(struct page *);
 extern void __cleancache_invalidate_page(struct address_space *, struct page *);
 extern void __cleancache_invalidate_inode(struct address_space *);
 extern void __cleancache_invalidate_fs(struct super_block *);
-extern int cleancache_enabled;
 
 #ifdef CONFIG_CLEANCACHE
+#define cleancache_enabled (1)
 static inline bool cleancache_fs_enabled(struct page *page)
 {
         return page->mapping->host->i_sb->cleancache_poolid >= 0;
diff --git a/mm/cleancache.c b/mm/cleancache.c
index b3ae19b72035..5875f48ce279 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -19,16 +19,6 @@
 #include <linux/cleancache.h>
 
 /*
- * This global enablement flag may be read thousands of times per second
- * by cleancache_get/put/invalidate even on systems where cleancache_ops
- * is not claimed (e.g. cleancache is config'ed on but remains
- * disabled), so is preferred to the slower alternative: a function
- * call that checks a non-global.
- */
-int cleancache_enabled __read_mostly;
-EXPORT_SYMBOL(cleancache_enabled);
-
-/*
  * cleancache_ops is set by cleancache_ops_register to contain the pointers
  * to the cleancache "backend" implementation functions.
  */
@@ -414,7 +404,6 @@ static int __init init_cleancache(void)
                 fs_poolid_map[i] = FS_UNKNOWN;
                 shared_fs_poolid_map[i] = FS_UNKNOWN;
         }
-        cleancache_enabled = 1;
         return 0;
 }
 module_init(init_cleancache)