jump_label: remove bug.h, atomic.h dependencies for HAVE_JUMP_LABEL

The current jump_label.h includes bug.h for things such as WARN_ON().
This makes the header problematic for inclusion by kernel.h or any
headers that kernel.h includes, since bug.h includes kernel.h (circular
dependency).  The inclusion of atomic.h is similarly problematic.  Thus,
this should make jump_label.h 'includable' from most places.

Link: http://lkml.kernel.org/r/7060ce35ddd0d20b33bf170685e6b0fab816bdf2.1467837322.git.jbaron@akamai.com
Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 23 insertions, 23 deletions

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 68904469fba1..661af564fae8 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -76,7 +76,6 @@
 
 #include <linux/types.h>
 #include <linux/compiler.h>
-#include <linux/bug.h>
 
 extern bool static_key_initialized;
 
@@ -115,20 +114,8 @@ enum jump_label_type {
 
 struct module;
 
-#include <linux/atomic.h>
-
 #ifdef HAVE_JUMP_LABEL
 
-static inline int static_key_count(struct static_key *key)
-{
-	/*
-	 * -1 means the first static_key_slow_inc() is in progress.
-	 *  static_key_enabled() must return true, so return 1 here.
-	 */
-	int n = atomic_read(&key->enabled);
-	return n >= 0 ? n : 1;
-}
-
 #define JUMP_TYPE_FALSE	0UL
 #define JUMP_TYPE_TRUE	1UL
 #define JUMP_TYPE_MASK	1UL
@@ -157,16 +144,29 @@ extern int jump_label_text_reserved(void *start, void *end);
 extern void static_key_slow_inc(struct static_key *key);
 extern void static_key_slow_dec(struct static_key *key);
 extern void jump_label_apply_nops(struct module *mod);
+extern int static_key_count(struct static_key *key);
+extern void static_key_enable(struct static_key *key);
+extern void static_key_disable(struct static_key *key);
 
+/*
+ * We should be using ATOMIC_INIT() for initializing .enabled, but
+ * the inclusion of atomic.h is problematic for inclusion of jump_label.h
+ * in 'low-level' headers. Thus, we are initializing .enabled with a
+ * raw value, but have added a BUILD_BUG_ON() to catch any issues in
+ * jump_label_init() see: kernel/jump_label.c.
+ */
 #define STATIC_KEY_INIT_TRUE					\
-	{ .enabled = ATOMIC_INIT(1),				\
+	{ .enabled = { 1 },					\
 	  .entries = (void *)JUMP_TYPE_TRUE }
 #define STATIC_KEY_INIT_FALSE					\
-	{ .enabled = ATOMIC_INIT(0),				\
+	{ .enabled = { 0 },					\
 	  .entries = (void *)JUMP_TYPE_FALSE }
 
 #else  /* !HAVE_JUMP_LABEL */
 
+#include <linux/atomic.h>
+#include <linux/bug.h>
+
 static inline int static_key_count(struct static_key *key)
 {
 	return atomic_read(&key->enabled);
@@ -216,14 +216,6 @@ static inline int jump_label_apply_nops(struct module *mod)
 	return 0;
 }
 
-#define STATIC_KEY_INIT_TRUE	{ .enabled = ATOMIC_INIT(1) }
-#define STATIC_KEY_INIT_FALSE	{ .enabled = ATOMIC_INIT(0) }
-
-#endif	/* HAVE_JUMP_LABEL */
-
-#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE
-#define jump_label_enabled static_key_enabled
-
 static inline void static_key_enable(struct static_key *key)
 {
 	int count = static_key_count(key);
@@ -244,6 +236,14 @@ static inline void static_key_disable(struct static_key *key)
 		static_key_slow_dec(key);
 }
 
+#define STATIC_KEY_INIT_TRUE	{ .enabled = ATOMIC_INIT(1) }
+#define STATIC_KEY_INIT_FALSE	{ .enabled = ATOMIC_INIT(0) }
+
+#endif	/* HAVE_JUMP_LABEL */
+
+#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE
+#define jump_label_enabled static_key_enabled
+
 /* -------------------------------------------------------------------------- */
 
 /*