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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 04630C18E5B for ; Mon, 16 Mar 2020 21:44:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB29F205ED for ; Mon, 16 Mar 2020 21:44:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="n7TUMxfS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732768AbgCPVow (ORCPT ); Mon, 16 Mar 2020 17:44:52 -0400 Received: from mail-pj1-f68.google.com ([209.85.216.68]:39348 "EHLO mail-pj1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732652AbgCPVow (ORCPT ); Mon, 16 Mar 2020 17:44:52 -0400 Received: by mail-pj1-f68.google.com with SMTP id d8so9373007pje.4 for ; Mon, 16 Mar 2020 14:44:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=D3D+qRAc+7oS8J6Sb2B1Mz4hpBLBqFH8O13t3FcfVa4=; b=n7TUMxfS05q1sAGxhXfS9KBXthw4r/gV1wXyY3/HpwXnOs+Yf4tGf5oszH9qukZVML Woma4yNpxC5KWOU6oTIBDHv/5/ZOV5plbE8NVxCxOmEAK+nVWI0W/MmSWVPVSwDdtLha skblwS0q9kA8z6T7FDwQcwTZJI1UofMPLd8rpqDlQPEwCp5TdX+CJh3xxCQGkTKFDLX6 lxXaJPjSxD8mLnFCjTOTifmCJ5qyABOPd/kHcOZDE077fAGrmFbdZD5eUu/aC8F8FGMq cLG3FOnrfaRSlMtmlqvG0zr4Wtew6oQhNzY8Xm3csG5EPY3Fn56nbQAhcKNGnt+WVg7g inrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=D3D+qRAc+7oS8J6Sb2B1Mz4hpBLBqFH8O13t3FcfVa4=; b=RCZsvzRWgLhMVAbnWeYVsv+eEhMRxwXQ1SEHI3jtemNVsbI6i8rt9PTvPwBR0oT6v/ SwmcLh98k/fu+z690kzEJxywGxQzBKa3NxW/vW3TFvGvpf8ZwhEE7feLR63O1IBeJx/h 1OEQckKsn5FLRIxoaurljv0O8ndpg7RYPM69Lxc4c0pFIJlOqLAQ61zRJwZMEoQwPrMY oCQ3Dr8TIUa6iJqkgT1VVDg5J4I6T+ly7XzBuDFE5szpsXKLNo2YMe9J0esNZW6D3WrZ izyS54jcQ0UjaqqtRT9L4zlBKeEdqY3KSzmuWsohbBTfmibvxJ/G1v5jOiWX4caGRse7 s7JA== X-Gm-Message-State: ANhLgQ1MwWy46aHGNFL/E5NevJE7SwhhPo8T/GvPCUcBkDa/ReChNSzD W+snIboXAztoSEMrIgW2EDIQvOtO X-Google-Smtp-Source: ADFU+vs60R8/j/ZW6FCkLMviIra7UhFL+U4BLcl8OYqLfjSUIx79EqZSX89WiGJDT2CyWWVnFVsKfg== X-Received: by 2002:a17:902:b118:: with SMTP id q24mr1265410plr.0.1584395091130; Mon, 16 Mar 2020 14:44:51 -0700 (PDT) Received: from Asurada-Nvidia.nvidia.com (thunderhill.nvidia.com. [216.228.112.22]) by smtp.gmail.com with ESMTPSA id j1sm812274pfg.64.2020.03.16.14.44.50 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 16 Mar 2020 14:44:51 -0700 (PDT) Date: Mon, 16 Mar 2020 14:45:06 -0700 From: Nicolin Chen To: Christoph Hellwig Cc: robin.murphy@arm.com, m.szyprowski@samsung.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: Re: [RFC][PATCH] dma-mapping: align default segment_boundary_mask with dma_mask Message-ID: <20200316214506.GC18970@Asurada-Nvidia.nvidia.com> References: <20200314000007.13778-1-nicoleotsuka@gmail.com> <20200316124850.GB17386@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200316124850.GB17386@lst.de> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoph, On Mon, Mar 16, 2020 at 01:48:50PM +0100, Christoph Hellwig wrote: > On Fri, Mar 13, 2020 at 05:00:07PM -0700, Nicolin Chen wrote: > > @@ -736,7 +736,7 @@ static inline unsigned long dma_get_seg_boundary(struct device *dev) > > { > > if (dev->dma_parms && dev->dma_parms->segment_boundary_mask) > > return dev->dma_parms->segment_boundary_mask; > > - return DMA_BIT_MASK(32); > > + return (unsigned long)dma_get_mask(dev); > > Just thinking out loud after my reply - shouldn't we just return ULONG_MAX > by default here to mark this as no limit? Yea, ULONG_MAX (saying no limit) sounds good to me.