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SubjectRe: [PATCH 01/12] perf/breakpoint: Split attribute parse and commit
Date
Frederic Weisbecker <frederic@kernel.org> writes:

> On Thu, May 24, 2018 at 11:56:01AM +1000, Michael Ellerman wrote:
>> Frederic Weisbecker <frederic@kernel.org> writes:
>>
>> > diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
>> > index 6e28d28..51320c2 100644
>> > --- a/kernel/events/hw_breakpoint.c
>> > +++ b/kernel/events/hw_breakpoint.c
>> > @@ -424,19 +443,22 @@ static int validate_hw_breakpoint(struct perf_event *bp)
>> >
>> > int register_perf_hw_breakpoint(struct perf_event *bp)
>> > {
>> > - int ret;
>> > + struct arch_hw_breakpoint hw;
>> > + int err;
>> >
>> > - ret = reserve_bp_slot(bp);
>> > - if (ret)
>> > - return ret;
>> > + err = reserve_bp_slot(bp);
>> > + if (err)
>> > + return err;
>> >
>> > - ret = validate_hw_breakpoint(bp);
>> > -
>> > - /* if arch_validate_hwbkpt_settings() fails then release bp slot */
>> > - if (ret)
>> > + err = hw_breakpoint_parse(bp, &bp->attr, &hw);
>>
>> Is there a good reason we pass bp and bp->attr? (I assume so)
>>
>> That added to the confusion in the existing code I think.
>
> Yes, on breakpoint creation (which is the above function) it's not needed
> but breakpoint modification wants it as we need to pass the attr that are
> to be validated, and those are not yet copied to the breakpoint at this
> stage. This happens in the end of the series.

OK thanks.

cheers

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