linux-kernel - RE: [PATCH 3/4] SunRPC: Use no_printk() for the null dprintk() and dfprintk()

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Date:	Thu, 26 Sep 2013 15:42:41 +0000
From:	"Myklebust, Trond" <Trond.Myklebust@...app.com>
To:	David Howells <dhowells@...hat.com>, Joe Perches <joe@...ches.com>
CC:	"bfields@...ldses.org" <bfields@...ldses.org>,
	"olof@...om.net" <olof@...om.net>,
	"linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 3/4] SunRPC: Use no_printk() for the null dprintk() and
 dfprintk()

> -----Original Message-----
> From: David Howells [mailto:dhowells@...hat.com]
> Sent: Thursday, September 26, 2013 10:36 AM
> To: Joe Perches
> Cc: dhowells@...hat.com; bfields@...ldses.org; Myklebust, Trond;
> olof@...om.net; linux-nfs@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 3/4] SunRPC: Use no_printk() for the null dprintk() and
> dfprintk()
> 
> Joe Perches <joe@...ches.com> wrote:
> 
> > no_printk doesn't prevent any argument side-effects from being
> > optimized away by the compiler.
> >
> > ie:
> > 	dprintk("%d", func())
> > func is now always called when before it wasn't.
> 
> Yes, I know.  There are half a dozen places where this is the case.  Those I've
> wrapped in ifdebug(FACILITY) { ... } in the code.  It's not the nicest, but at
> least the compiler always gets to see everything, rather than bits of it getting
> hidden by the preprocessor - which means the call points will be less likely to
> bit rot over time.

Your assumption is that RPC_DEBUG is disabled for most compiles. That is not the case.

Trond
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