Date: Mon, 3 Nov 2014 18:39:14 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vince@deater.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
        Stephane Eranian <eranian@google.com>, Ingo Molnar <mingo@kernel.org>,
        Jiri Olsa <jolsa@redhat.com>, Andy Lutomirski <luto@amacapital.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFD] perf syscall error handling
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On Mon, Nov 03, 2014 at 12:12:18PM -0500, Vince Weaver wrote:
> I don't know if having an offset/mask helps much.  Knowing your EINVAL
> comes from ->config is nice to know, but if there's 30 different ways
> to get an EINVAL from an improper config then you still can waste a lot
> of time narrowing things down.
> 
> The string solution might be nice, but it is going to take major changes 
> to the code and increase the size a bit.  For example:
> 
> $ cat arch/x86/kernel/cpu/perf* kernel/events/* | grep EINVAL | wc -l
> 100
> 
> And some of the code is passing the return values back through various
> long callchains (and overloaded pointers via casts) where it's not clear 
> how you could also pass a string value.

Yes, nobody said this would be a quick and easy exercise. But I figure
something needs to happen.
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