Re: [PATCH v2 net-next] bpf: fix bpf_perf_event_read() helper

[Wangnan (F)]

On 2015/10/22 14:21, Alexei Starovoitov wrote:
> On 10/21/15 10:31 PM, Wangnan (F) wrote:
> > > +    if ((attr->type != PERF_TYPE_RAW &&
> > > +         !(attr->type == PERF_TYPE_SOFTWARE &&
> > > +           attr->config == PERF_COUNT_SW_BPF_OUTPUT) &&
> > > +         attr->type != PERF_TYPE_HARDWARE) ||
> > > +        attr->inherit) {
> >
> > This 'if' statement is so complex. What about using a inline function
> > instead?
>
> hmm. don't see how inline function will help readability.

For example (not tested):

 static inline bool perf_event_can_insert_to_map(struct perf_event_attr 
*attr)
 {
    /* is inherit? */
    if (attr->inherit)
        return false;

    /* is software event? */
    if (attr->type == PERF_TYPE_SOFTWARE)
        if (attr->config == PERF_COUNT_SW_BPF_OUTPUT)
            return true;
        else
            return false;

    /* Comment... */
    if (attr->type == PERF_TYPE_RAW)
        return true;
    if (attr->type == PERF_TYPE_HARDWARE)
        return true;
    return false;
 }

 ...
 if (!perf_event_can_insert_to_map(attr))
    ....

Do you think redability is improved?

Thank you.

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