Re: [PATCH v4 07/11] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head()

[Leo Yan]

On Mon, Jul 12, 2021 at 05:32:11PM +0300, Adrian Hunter wrote:

[...]

> > --- a/tools/perf/util/auxtrace.c
> > +++ b/tools/perf/util/auxtrace.c
> > @@ -1686,13 +1686,12 @@ static int __auxtrace_mmap__read(struct mmap *map,
> >  	union perf_event ev;
> >  	void *data1, *data2;
> >  
> > +	head = auxtrace_mmap__read_head(mm);
> > +
> >  	if (snapshot) {
> > -		head = auxtrace_mmap__read_snapshot_head(mm);
> >  		if (auxtrace_record__find_snapshot(itr, mm->idx, mm, data,
> >  						   &head, &old))
> 
> That leaves a nested 'if' which is not kernel style i.e. could be
> 
> 	if (snapshot &&
> 	    auxtrace_record__find_snapshot(itr, mm->idx, mm, data, &head, &old))

Will refine in next spin, thanks for suggestion!

> >  			return -1;
> > -	} else {
> > -		head = auxtrace_mmap__read_head(mm);
> >  	}
> >  
> >  	if (old == head)