From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f177.google.com (mail-pd0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id 9F6EC6B0138 for ; Mon, 9 Dec 2013 19:50:48 -0500 (EST) Received: by mail-pd0-f177.google.com with SMTP id q10so6177215pdj.36 for ; Mon, 09 Dec 2013 16:50:48 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTP id q8si8772306pav.173.2013.12.09.16.50.46 for ; Mon, 09 Dec 2013 16:50:47 -0800 (PST) Date: Mon, 9 Dec 2013 16:50:44 -0800 From: Andrew Morton Subject: Re: [PATCH] mm: nobootmem: avoid type warning about alignment value Message-Id: <20131209165044.cf7de2edb8f4205d5ac02ab0@linux-foundation.org> In-Reply-To: <52935762.1080409@ti.com> References: <1385249326-9089-1-git-send-email-santosh.shilimkar@ti.com> <529217C7.6030304@cogentembedded.com> <52935762.1080409@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Santosh Shilimkar Cc: Sergei Shtylyov , linux-kernel@vger.kernel.org, Tejun Heo , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org 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? -- 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