staging: zcache: enable zcache to be built/loaded as a module

Allow zcache to be built/loaded as a module.  Note runtime dependency
disallows loading if cleancache/frontswap lazy initialization patches
are not present.  Zsmalloc support has not yet been merged into zcache
but, once merged, could now easily be selected via a module_param.

If built-in (not built as a module), the original mechanism of enabling
via a kernel boot parameter is retained, but this should be considered
deprecated.

Note that module unload is explicitly not yet supported.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v1: Rebased with different order of patches]
[v2: Removed [CLEANCACHE|FRONTSWAP]_HAS_LAZY_INIT ifdef]
[v3: Rebased on top of ramster->zcache move]
[v4: Redid the Makefile]
[v5: s/ZCACHE2/ZCACHE/]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.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>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/staging/zcache/zcache.h b/drivers/staging/zcache/zcache.h
index 81722b33b087..849120095e79 100644
--- a/drivers/staging/zcache/zcache.h
+++ b/drivers/staging/zcache/zcache.h
@@ -39,7 +39,7 @@ extern int zcache_flush_page(int, int, struct tmem_oid *, uint32_t);
 extern int zcache_flush_object(int, int, struct tmem_oid *);
 extern void zcache_decompress_to_page(char *, unsigned int, struct page *);
 
-#ifdef CONFIG_RAMSTER
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
 extern void *zcache_pampd_create(char *, unsigned int, bool, int,
 				struct tmem_handle *);
 int zcache_autocreate_pool(unsigned int cli_id, unsigned int pool_id, bool eph);