mm,x86,um: move CMPXCHG_DOUBLE config option

Move CMPXCHG_DOUBLE and rename it to HAVE_CMPXCHG_DOUBLE so architectures
can simply select the option if it is supported.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/Kconfig

@@ -196,4 +196,7 @@ config HAVE_ALIGNED_STRUCT_PAGE
 config HAVE_CMPXCHG_LOCAL
 	bool
 
+config HAVE_CMPXCHG_DOUBLE
+	bool
+
 source "kernel/gcov/Kconfig"

arch/x86/Kconfig

@@ -62,6 +62,7 @@ config X86
 	select ANON_INODES
 	select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
 	select HAVE_CMPXCHG_LOCAL if !M386
+	select HAVE_CMPXCHG_DOUBLE
 	select HAVE_ARCH_KMEMCHECK
 	select HAVE_USER_RETURN_NOTIFIER
 	select ARCH_BINFMT_ELF_RANDOMIZE_PIE

arch/x86/Kconfig.cpu

@@ -309,9 +309,6 @@ config X86_INTERNODE_CACHE_SHIFT
 config X86_CMPXCHG
 	def_bool X86_64 || (X86_32 && !M386)
 
-config CMPXCHG_DOUBLE
-	def_bool y
-
 config X86_L1_CACHE_SHIFT
 	int
 	default "7" if MPENTIUM4 || MPSC

arch/x86/um/Kconfig

@@ -6,10 +6,6 @@ menu "UML-specific options"
 
 menu "Host processor type and features"
 
-config CMPXCHG_DOUBLE
-	bool
-	default n
-
 source "arch/x86/Kconfig.cpu"
 
 endmenu

mm/slub.c

@@ -366,7 +366,8 @@ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page
 		const char *n)
 {
 	VM_BUG_ON(!irqs_disabled());
-#if defined(CONFIG_CMPXCHG_DOUBLE) && defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 	if (s->flags & __CMPXCHG_DOUBLE) {
 		if (cmpxchg_double(&page->freelist, &page->counters,
 			freelist_old, counters_old,
@@ -400,7 +401,8 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 		void *freelist_new, unsigned long counters_new,
 		const char *n)
 {
-#if defined(CONFIG_CMPXCHG_DOUBLE) && defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 	if (s->flags & __CMPXCHG_DOUBLE) {
 		if (cmpxchg_double(&page->freelist, &page->counters,
 			freelist_old, counters_old,
@@ -3014,7 +3016,8 @@ static int kmem_cache_open(struct kmem_cache *s,
 		}
 	}
 
-#if defined(CONFIG_CMPXCHG_DOUBLE) && defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 	if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
 		/* Enable fast mode */
 		s->flags |= __CMPXCHG_DOUBLE;