From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH V3] trace/events: add chip name and hwirq to irq entry
 tracepoint
Date: Sun, 5 Jul 2015 23:28:44 +0200 (CEST)
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References: <1435162650-32266-1-git-send-email-ankgupta@codeaurora.org> <20150624124227.1cddbbac@gandalf.local.home>
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ankit Gupta <ankgupta@codeaurora.org>, mingo@redhat.com, agross@codeaurora.org, davem@davemloft.net, rdunlap@infradead.org, standby24x7@gmail.com, sboyd@codeaurora.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, gavidov@codeaurora.org, sdharia@codeaurora.org, linux-arm-msm@vger.kernel.org, mlocke@codeaurora.org

On Wed, 24 Jun 2015, Steven Rostedt wrote:
> > +
> > +#define show_chip_name(irq)					\
> > +	(irq_get_irq_data(irq)					\
> > +			 ? irq_get_irq_data(irq)->chip->name	\
> > +			 : "NULL")
> > +
> > +#define show_hwirq(irq)						\
> > +	(irq_get_irq_data(irq)					\
> > +			 ? irq_get_irq_data(irq)->hwirq		\
> > +			 : -ENODEV)
> 
> Note these magic functions will only be useful for the tracefs reads of
> the trace files. Userspace tools that extract the data (like perf and
> trace-cmd), will have no idea of how to parse it.
> 
> I'm not against doing this, but I'm just letting you know what the
> effect of this change will be.

What's worse is, that they are racy against a concurrent teardown of
the interrupt. Not a good idea ...

Thanks,

	tglx