+ LOCK_SECTION_START("") \
+ "2:\tcall " helper "\n\t" \
+ "jmp 1b\n" \
+ LOCK_SECTION_END \
+ ::"a" (rw) : "memory")
+
+#define __build_write_lock_const(rw, helper) \
+ asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
+ "jnz 2f\n" \
+ "1:\n" \
+ LOCK_SECTION_START("") \
+ "2:\tpushq %%rax\n\t" \
+ "leaq %0,%%rax\n\t" \
+ "call " helper "\n\t" \
+ "popq %%rax\n\t" \
+ "jmp 1b\n" \
+ LOCK_SECTION_END \
+ :"=m" (*((volatile long *)rw))::"memory")
+
+#define __build_write_lock(rw, helper) do { \
+ if (__builtin_constant_p(rw)) \
+ __build_write_lock_const(rw, helper); \
+ else \
+ __build_write_lock_ptr(rw, helper); \
+ } while (0)