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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 27740C2BA1A for ; Mon, 6 Apr 2020 21:06:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3D94206B8 for ; Mon, 6 Apr 2020 21:06:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VNG6cwoh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726467AbgDFVGm (ORCPT ); Mon, 6 Apr 2020 17:06:42 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:33162 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725933AbgDFVGm (ORCPT ); Mon, 6 Apr 2020 17:06:42 -0400 Received: by mail-pl1-f196.google.com with SMTP id ay1so364360plb.0 for ; Mon, 06 Apr 2020 14:06:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=F7oyQrycdBGvwHlAg5l8DJr2cSrN+vxfu/5R7n9PHnM=; b=VNG6cwohDXNRbJGMuO22h1hA4687il974YFacYVjjW0YaZFR++a3HGfBJJ7qYyat6E Pqlj+VbHwHV5dgg4V3abZvK3Jx7HPojHNnppBCGjRmy5zttmIJEFyNmrgYnSlX32hMra 3yXr+RSEkAemaAarNl/R7E2W+XqlWrwkrZ/jic14gRTFGVhiuH5wte6NfiUD7YqHiRRz nMsqJ/TPb0p0LRYuqFU6gnBkw7sHpqIXM6WIR13FaknYRtX1Vkxc7xonlfLQ2D/jHtDh Zks1+3n/eKOHAbsFpvOjiIML7IcRhrRuBzyGI2up5/9vtpyFnNp5mxH2BQ4a4JGo7Qt/ Rtrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=F7oyQrycdBGvwHlAg5l8DJr2cSrN+vxfu/5R7n9PHnM=; b=fl1W7k2NDpEaBlYa8Wv5nkvqgqv+ZjnXU6AsZ9wn0IcZ9O8mwUzSKIMvygegF5+Var ZLsfm4aKcaDWsiD1I5GIT25l8o/PlpojxC0swywI45enYPDvxxLLNVcSeDu4g6WbxGQX Tm4K0+XvLTn+WMZ+I/0liM9UFF6s/3naSxpWsCyzgSbCH4NHjKL20ol+Pk+7vEeNH+vD aMLHEKALwa0uIXGs3fQRB8RbeFTzNX0IqcaTU8iQeBuhBrjtyqQ1hynTUDo5ClZ6CNYx Zcl+JzNorHMeyrcM1tNlhlmFZiAc66y1c6iT32HSFJc43mntUfyPMBIFq43MabCm6TxU dgmA== X-Gm-Message-State: AGi0PuYmPn96jad1DCr7TwTO3K6SDy1pRWS44DqpylewrUihEkxWYt4Y EHpV8uNhwcxQkBHbainI10E= X-Google-Smtp-Source: APiQypKJbIkLMaBwh90y6jKxYqWc9V67C01F47EfkGfkWEkFa7Vx6ItiZnoObiuN7fiA/whRFXG+Dg== X-Received: by 2002:a17:902:bd02:: with SMTP id p2mr22035795pls.67.1586207201046; Mon, 06 Apr 2020 14:06:41 -0700 (PDT) Received: from Asurada-Nvidia.nvidia.com (thunderhill.nvidia.com. [216.228.112.22]) by smtp.gmail.com with ESMTPSA id d71sm12427134pfd.46.2020.04.06.14.06.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Apr 2020 14:06:40 -0700 (PDT) From: Nicolin Chen To: robin.murphy@arm.com, m.szyprowski@samsung.com, hch@lst.de Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: [RFC/RFT][PATCH v2] dma-mapping: set default segment_boundary_mask to ULONG_MAX Date: Mon, 6 Apr 2020 14:06:43 -0700 Message-Id: <20200406210643.20665-1-nicoleotsuka@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The default segment_boundary_mask was set to DMA_BIT_MAKS(32) a decade ago by referencing SCSI/block subsystem, as a 32-bit mask was good enough for most of the devices. Now more and more drivers set dma_masks above DMA_BIT_MAKS(32) while only a handful of them call dma_set_seg_boundary(). This means that most drivers have a 4GB segmention boundary because DMA API returns a 32-bit default value, though they might not really have such a limit. The default segment_boundary_mask should mean "no limit" since the device doesn't explicitly set the mask. But a 32-bit mask certainly limits those devices capable of 32+ bits addressing. So this patch sets default segment_boundary_mask to ULONG_MAX. Signed-off-by: Nicolin Chen --- Changelog: v1->v2 * Followed Robin's comments to revise the commit message by dropping one paragraph of not-entirely-true justification (no git-diff level change, so please ack if you tested v1) include/linux/dma-mapping.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 330ad58fbf4d..ff8cefe85f30 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -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 ULONG_MAX; } static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask) -- 2.17.1