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Date: Fri, 16 Jan 2015 08:30:49 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Javi Merino <javi.merino@arm.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Dave P Martin <Dave.Martin@arm.com>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [RESEND PATCH v2 1/2] tracing: Add array printing helpers
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On Fri, 16 Jan 2015 10:14:14 +0000
Javi Merino <javi.merino@arm.com> wrote:


> > BUG() is a bit extreme don't you think? I'm not sure it even
> > deserves a WARN_ON().
> 
> Ok, I used BUG() because that's what you suggested:
> 
> http://article.gmane.org/gmane.linux.kernel/1846749
> 

Whoever suggested that was an idiot ;-)

I know why I suggested that but looking at it again with a clearer head
I think it's better not to bug, or even warn. It's on the output side,
for some reason I was thinking it was on the input (saving to buffer)
side.

> The only way I could think of turning it into a BUILD_BUG was by
> moving it to the __print_array macro, but I think it's ugly.

BUILD_BUG is probably better even if it is ugly. But for now, as this
is only to output the data not to save it, printing is better.

> 
> > I would suggest doing:
> > 
> > 			trace_seq_printf(p, "BAD SIZE:%d 0x%x",
> > el_size, *(u8 *)ptr);
> > 			el_size = 8;
> > 
> > No need to go crashing the kernel or even messing with dmesg over
> > somebody's tracepoint mistake.
> 
> Ok, I'll change it to that.
> 
> > The rest looks fine.
> > 
> > > +		}
> > > +		prefix = ",";
> > > +		ptr += el_size / 8;
> > > +	}
> > > +
> > > +	trace_seq_putc(p, '}');
> > > +	trace_seq_putc(p, 0);
> > 
> > I need to add a trace_seq_terminate() for this.
> 
> That would make it more readable.  Cheers,

It's on my todo list :-)

Thanks!

-- Steve