[PATCH V6 31/33] csky: fix compile error in linux/bug.h with SMP enabled

[Guo Ren]

In linux-4.19 we couldn't include linux/bug.h here when SMP enabled.
It'll cause compile error for bad include.

In file included from ./arch/csky/include/asm/bitops.h:70:0,
                 from ./include/linux/bitops.h:19,
                 from ./include/linux/kernel.h:11,
                 from ./include/asm-generic/bug.h:18,
                 from ./arch/csky/include/asm/bug.h:19,
                 from ./include/linux/bug.h:5,
                 from ./arch/csky/include/asm/cmpxchg.h:6,
                 from ./arch/csky/include/asm/atomic.h:8,
                 from ./include/linux/atomic.h:7,
                 from ./include/linux/rcupdate.h:38,
                 from ./include/linux/init_task.h:5,
                 from init/init_task.c:2:

The asm/bitops.h will lose asm/atomic.h for cycle include.

Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
---
 arch/csky/include/asm/cmpxchg.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/csky/include/asm/cmpxchg.h b/arch/csky/include/asm/cmpxchg.h
index 9b63dd7..ad53006 100644
--- a/arch/csky/include/asm/cmpxchg.h
+++ b/arch/csky/include/asm/cmpxchg.h
@@ -2,9 +2,10 @@
 #define __ASM_CSKY_CMPXCHG_H
 
 #ifdef CONFIG_CPU_HAS_LDSTEX
-#include <linux/bug.h>
 #include <asm/barrier.h>
 
+extern void __bad_xchg(volatile void *ptr, int size);
+
 #define __xchg(new, ptr, size)					\
 ({								\
 	__typeof__(ptr) __ptr = (ptr);				\
@@ -25,7 +26,7 @@
 		smp_mb();					\
 		break;						\
 	default:						\
-		BUILD_BUG();					\
+		__bad_xchg(ptr, size), __ret = 0;		\
 	}							\
 	__ret;							\
 })
@@ -56,7 +57,7 @@
 		smp_mb();					\
 		break;						\
 	default:						\
-		BUILD_BUG();					\
+		__bad_xchg(ptr, size), __ret = 0;		\
 	}							\
 	__ret;							\
 })
-- 
2.7.4