From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F62CC433E0 for ; Thu, 11 Feb 2021 08:06:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5BE9864E7D for ; Thu, 11 Feb 2021 08:06:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229968AbhBKIEx (ORCPT ); Thu, 11 Feb 2021 03:04:53 -0500 Received: from verein.lst.de ([213.95.11.211]:54394 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229690AbhBKIES (ORCPT ); Thu, 11 Feb 2021 03:04:18 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 244AE68BFE; Thu, 11 Feb 2021 09:04:17 +0100 (CET) Date: Thu, 11 Feb 2021 09:04:17 +0100 From: Christoph Hellwig To: Anshuman Khandual Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, akpm@linux-foundation.org, will@kernel.org, Robin Murphy , Marek Szyprowski , Christoph Hellwig , David Hildenbrand , Mark Rutland , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] dma-contiguous: Type cast MAX_ORDER as unsigned int Message-ID: <20210211080417.GC14448@lst.de> References: <1613024531-19040-1-git-send-email-anshuman.khandual@arm.com> <1613024531-19040-4-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1613024531-19040-4-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 11, 2021 at 11:52:11AM +0530, Anshuman Khandual wrote: > Type cast MAX_ORDER as unsigned int to fix the following build warning. > > In file included from ./include/linux/kernel.h:14, > from ./include/asm-generic/bug.h:20, > from ./arch/arm64/include/asm/bug.h:26, > from ./include/linux/bug.h:5, > from ./include/linux/mmdebug.h:5, > from ./arch/arm64/include/asm/memory.h:166, > from ./arch/arm64/include/asm/page.h:42, > from kernel/dma/contiguous.c:46: > kernel/dma/contiguous.c: In function ‘rmem_cma_setup’: > ./include/linux/minmax.h:18:28: warning: comparison of distinct pointer > types lacks a cast > (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) > ^~ > ./include/linux/minmax.h:32:4: note: in expansion of macro ‘__typecheck’ > (__typecheck(x, y) && __no_side_effects(x, y)) > ^~~~~~~~~~~ > ./include/linux/minmax.h:42:24: note: in expansion of macro ‘__safe_cmp’ > __builtin_choose_expr(__safe_cmp(x, y), \ > ^~~~~~~~~~ > ./include/linux/minmax.h:58:19: note: in expansion of macro > ‘__careful_cmp’ > #define max(x, y) __careful_cmp(x, y, >) > ^~~~~~~~~~~~~ > kernel/dma/contiguous.c:402:35: note: in expansion of macro ‘max’ > phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); > > Cc: Christoph Hellwig > Cc: Marek Szyprowski > Cc: Robin Murphy > Cc: iommu@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > kernel/dma/contiguous.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c > index 3d63d91cba5c..1c2782349d71 100644 > --- a/kernel/dma/contiguous.c > +++ b/kernel/dma/contiguous.c > @@ -399,7 +399,7 @@ static const struct reserved_mem_ops rmem_cma_ops = { > > static int __init rmem_cma_setup(struct reserved_mem *rmem) > { > - phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); > + phys_addr_t align = PAGE_SIZE << max((unsigned int)MAX_ORDER - 1, pageblock_order); MAX_ORDER and pageblock_order should be the same type. So either fix MAX_ORDER to be an unsigned constant, which would be fundamentally the right thing to do but might cause some fallout, or turn pageblock_order into an int, which is probably much either as the stub define of it already has an integer type derived from MAX_ORDER as well.