On Tue, 26 Oct 2021 17:48:10 +0800 王贇 <yun.w...@linux.alibaba.com> wrote:
> > The two comments should be updated too since Steven removed the "bit == 0" > > trick. > > Could you please give more hint on how will it be correct? > > I get the point that bit will no longer be 0, there are only -1 or > 0 now > so trace_test_and_set_recursion() will disable preemption on bit > 0 and > trace_clear_recursion() will enabled it since it should only be called when > bit > 0 (I remember we could use a WARN_ON here now :-P). > > > > >> @@ -178,7 +187,7 @@ static __always_inline void trace_clear_recursion(int > >> bit) > >> * tracing recursed in the same context (normal vs interrupt), > >> * > >> * Returns: -1 if a recursion happened. > >> - * >= 0 if no recursion > >> + * > 0 if no recursion. > >> */ > >> static __always_inline int ftrace_test_recursion_trylock(unsigned long ip, > >> unsigned long > >> parent_ip) > > > > And this change would not be correct now. > > I thought it will no longer return 0 so I change it to > 0, isn't that > correct? No it is not. I removed the bit + 1 return value, which means it returns the actual bit now. Which is 0 or more. -- Steve
