Message-ID: <1379639226.5862.9.camel@joe-AO722>
Subject: Re: [PATCH 5/5] lib: Add error string support to printks
From: Joe Perches <joe@perches.com>
To: Daniel Santos <daniel.santos@pobox.com>
Cc: David Howells <dhowells@redhat.com>,
        linux-kbuild <linux-kbuild@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, Michal Marek <mmarek@suse.cz>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        George Spelvin <linux@horizon.com>
Date: Thu, 19 Sep 2013 18:07:06 -0700
In-Reply-To: <523A5316.50405@att.net>
References: <1379482610.1787.7.camel@joe-AO722>
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On Wed, 2013-09-18 at 20:27 -0500, Daniel Santos wrote:
> if I use ERR_PTR() on a signed int on a x86_64 where pointer 
> is 64 bits and int is 32, wouldn't that mean a signed conversion 
> instruction where the sign bit has to be moved from bit 31 to 63?

No.  It's cast to long

static inline void * __must_check ERR_PTR(long error)
{
	return (void *) error;
}

> Either way, %pE does seem to make a lot of sense for conditions where we 
> already have a pointer that we would otherwise use PTR_ERR() to convert, 
> but it just seems klunky to use it on an int, to have it treated like a 
> pointer and then re-interpreted as an int.  Maybe we can add %pE as well 
> as %dE and leave [ioxXu] out of it?

I think having just one way to format is better.


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