Date: Fri, 28 Feb 2014 21:46:21 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Vince Weaver <vincent.weaver@maine.edu>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@redhat.com>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Subject: Re: [PATCH] x86: Rename copy_from_user_nmi() to
 copy_from_user_trace()
Message-ID: <20140228204621.GA14089@laptop.programming.kicks-ass.net>
References: <alpine.DEB.2.10.1402272032140.6271@vincent-weaver-1.um.maine.edu>
 <20140227215726.7018c861@gandalf.local.home>
 <alpine.DEB.2.10.1402280914550.6727@vincent-weaver-1.um.maine.edu>
 <20140228092341.12a40f7c@gandalf.local.home>
 <alpine.DEB.2.10.1402280957470.6727@vincent-weaver-1.um.maine.edu>
 <1c583986-74f8-4829-883b-390dc49ddabb@email.android.com>
 <20140228154026.GH9987@twins.programming.kicks-ass.net>
 <5310B60F.30806@zytor.com>
 <20140228112946.1f194397@gandalf.local.home>
 <20140228143316.211d4034@gandalf.local.home>
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On Fri, Feb 28, 2014 at 02:33:16PM -0500, Steven Rostedt wrote:
> [ H. Peter, Here's the rename patch. I did not include your update. You
> can add that first and then massage this patch on top. But this isn't
> critical for mainline or stable, where as I believe your patch is. ]
> 
> The tracing utilities sometimes need to read from userspace (stack tracing),
> and to do this it has as special copy_from_user function called
> copy_from_user_nmi(). Well, as tracers can call this from outside of
> nmi context, the "_nmi" part is a misnomer and "_trace" is a better
> name.

NAK, spin_lock_irq() is very much an IRQ safe lock. Similarly
copy_from_user_nmi() is an NMI safe copy from user.

Furthermore, there's exactly 0 trace users, so the proposed name is
actively worse.
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