From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f48.google.com (mail-yh0-f48.google.com [209.85.213.48]) by kanga.kvack.org (Postfix) with ESMTP id 078DA6B013B for ; Mon, 9 Dec 2013 20:02:41 -0500 (EST) Received: by mail-yh0-f48.google.com with SMTP id f73so3363917yha.21 for ; Mon, 09 Dec 2013 17:02:41 -0800 (PST) Received: from comal.ext.ti.com (comal.ext.ti.com. [198.47.26.152]) by mx.google.com with ESMTPS id m9si11755374yha.173.2013.12.09.17.02.40 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 09 Dec 2013 17:02:41 -0800 (PST) Message-ID: <52A66826.7060204@ti.com> Date: Mon, 9 Dec 2013 20:02:30 -0500 From: Santosh Shilimkar MIME-Version: 1.0 Subject: Re: [PATCH] mm: nobootmem: avoid type warning about alignment value References: <1385249326-9089-1-git-send-email-santosh.shilimkar@ti.com> <529217C7.6030304@cogentembedded.com> <52935762.1080409@ti.com> <20131209165044.cf7de2edb8f4205d5ac02ab0@linux-foundation.org> <20131210005454.GX4360@n2100.arm.linux.org.uk> In-Reply-To: <20131210005454.GX4360@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Russell King - ARM Linux Cc: Andrew Morton , Tejun Heo , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergei Shtylyov , linux-arm-kernel@lists.infradead.org On Monday 09 December 2013 07:54 PM, Russell King - ARM Linux wrote: > On Mon, Dec 09, 2013 at 04:50:44PM -0800, Andrew Morton wrote: >> On Mon, 25 Nov 2013 08:57:54 -0500 Santosh Shilimkar wrote: >> >>> On Sunday 24 November 2013 10:14 AM, Sergei Shtylyov wrote: >>>> Hello. >>>> >>>> On 24-11-2013 3:28, Santosh Shilimkar wrote: >>>> >>>>> Building ARM with NO_BOOTMEM generates below warning. Using min_t >>>> >>>> Where is that below? :-) >>>> >>> Damn.. Posted a wrong version of the patch ;-( >>> Here is the one with warning message included. >>> >>> >From 571dfdf4cf8ac7dfd50bd9b7519717c42824f1c3 Mon Sep 17 00:00:00 2001 >>> From: Santosh Shilimkar >>> Date: Sat, 23 Nov 2013 18:16:50 -0500 >>> Subject: [PATCH] mm: nobootmem: avoid type warning about alignment value >>> >>> Building ARM with NO_BOOTMEM generates below warning. >>> >>> mm/nobootmem.c: In function _____free_pages_memory___: >>> mm/nobootmem.c:88:11: warning: comparison of distinct pointer types lacks a cast >>> >>> Using min_t to find the correct alignment avoids the warning. >>> >>> Cc: Tejun Heo >>> Cc: Andrew Morton >>> Signed-off-by: Santosh Shilimkar >>> --- >>> mm/nobootmem.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/mm/nobootmem.c b/mm/nobootmem.c >>> index 2c254d3..8954e43 100644 >>> --- a/mm/nobootmem.c >>> +++ b/mm/nobootmem.c >>> @@ -85,7 +85,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end) >>> int order; >>> >>> while (start < end) { >>> - order = min(MAX_ORDER - 1UL, __ffs(start)); >>> + order = min_t(size_t, MAX_ORDER - 1UL, __ffs(start)); >>> >> >> size_t makes no sense. Neither `order', `MAX_ORDER', 1UL nor __ffs() >> have that type. >> >> min() warnings often indicate that the chosen types are inappropriate, >> and suppressing them with min_t() should be a last resort. >> >> MAX_ORDER-1UL has type `unsigned long' (yes?) and __ffs() should return >> unsigned long (except arch/arc which decided to be different). >> >> Why does it warn? What's the underlying reason? > > The underlying reason is that - as I've already explained - ARM's __ffs() > differs from other architectures in that it ends up being an int, whereas > almost everyone else is unsigned long. > > The fix is to fix ARMs __ffs() to conform to other architectures. > I was just about to cross-post your reply here. Obviously I didn't think this far when I made $subject fix. So lets ignore the $subject patch which is not correct. Sorry for noise Regards, Santosh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org