cbqtrace
struct cbqtrace cbqtrace_buffer[NCBQTRACE+1];
struct cbqtrace *cbqtrace_ptr = NULL;
extern struct cbqtrace cbqtrace_buffer[];
extern struct cbqtrace *cbqtrace_ptr;
if ((struct cbqtrace *)(void *)_p >= &cbqtrace_buffer[NCBQTRACE])\
cbqtrace_ptr = (struct cbqtrace *)(void *)_p; \