From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1096172-1517922365-2-16097306100895365780 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: plain='utf-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-usb-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1517922364; b=rDby6JUS+vxGig77/e5IjTqJhP7zcVjfHWYV2Lv9GTJnY9H f+Bdr056q9lEz3DFQk9MTTKlPRyOHED+0JJOgAJF32vKRCAqNLYdK0jk3xFytz06 M7f/SjsF89GRVFVma3PjrX0xvOW7mRrA9Oidi5FkOhfITD8dxQtEGk1tUXMMMUlt qc2rGS4awYNaaLdCewgsJanIUDoY+gnftUcLBu2Oz3qUQt9O3BoYV8+Gy64zTZ2d HWo+U0vqREBdGXHAzpv9FXm1X4HnP6MWxwY/skeHRAJQ7yemPoC3qttTwGol6yQf dPXkSo5Ycw8KmXwS3O2GKN/0ZM87JcPZUw02IxQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=subject:to:cc:references:from:message-id :date:mime-version:in-reply-to:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1517922364; bh=ZdqIU0ZTVTNJKQpk3MyqvdmQ70MV6zVWfXICZB7v4TI=; b=w GkelPmkSwtWEnFmaHwD8UUoiDH3T1tqbze5eJpge8MepdTSlZOa66ziQW1jgj98Z fMXz8apeZu6avk2FSFrf4oQihC583K3yTkwTI70fMTAm4s1eF5VKXwJYcOfxIhBy ByF7j/c3rZ4UeV4yTJsNufwxslHh0+judsZaXoEw2ah9VXfNEwpI9lRj3KsmV+Xq HUTwZZ8HUwe4bvju64PfMAfzzMvcmuZO1+PDnH2dH62twsdWZHESmgkmZAleP4wx VZr1KjETtU6V0YI7bVcRkeBQG9TuYBXt2fjYnVk14bn+hlrQZVFefCEPUTrzku33 hJaqgRVwgHgf6oC2yh1qQ== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=arm.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-usb-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=arm.com header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=arm.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-usb-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=arm.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752733AbeBFNFu (ORCPT ); Tue, 6 Feb 2018 08:05:50 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:36726 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752246AbeBFNFs (ORCPT ); Tue, 6 Feb 2018 08:05:48 -0500 Subject: Re: [PATCH/RFC 0/6] Allow compile-testing NO_DMA To: Geert Uytterhoeven , Christoph Hellwig , Marek Szyprowski , Arnd Bergmann , Mark Brown , Richard Weinberger Cc: Felipe Balbi , Greg Kroah-Hartman , "James E . J . Bottomley" , "Martin K . Petersen" , iommu@lists.linux-foundation.org, linux-usb@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org References: <1517912092-15470-1-git-send-email-geert@linux-m68k.org> From: Robin Murphy Message-ID: Date: Tue, 6 Feb 2018 13:05:44 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1517912092-15470-1-git-send-email-geert@linux-m68k.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org X-Mailing-List: linux-usb@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 06/02/18 10:14, Geert Uytterhoeven wrote: > Hi all, > > If NO_DMA=y, get_dma_ops() returns a reference to the non-existing > symbol bad_dma_ops, thus causing a link failure if it is ever used. > > The intention of this is twofold: > 1. To catch users of the DMA API on systems that do no support the DMA > mapping API, > 2. To avoid building drivers that cannot work on such systems anyway. > > However, the disadvantage is that we have to keep on adding dependencies > on HAS_DMA all over the place. > > Thanks to the COMPILE_TEST symbol, lots of drivers now depend on one or > more platform dependencies (that imply HAS_DMA) || COMPILE_TEST, thus > already covering intention #2. Having to add an explicit dependency on > HAS_DMA here is cumbersome, and hinders compile-testing. > > Hence I think the time is ripe to reconsider the link failure. > This patch series: > - Changes get_dma_ops() to return NULL instead, > - Adds a few more dummies to enable compile-testing, > - Removes dependencies on HAS_DMA for symbols that already have > platform dependencies implying HAS_DMA. > > Note that adding more platform dependencies and/or dependencies on > COMPILE_TEST is encouraged! > > This may make life harder for UML, though, as UML usually satisfies all > other platform dependencies for HAS_DMA. Similarly, HAS_IOMEM is even > more complicated. Can/do we want to do something similar for > HAS_IOMEM? It looks like we have only one real arch (score) without IOMEM, and two (s390 and tile) where it is possible to configure out, so it does seem like a reasonable feature to assume. Maybe we could have something like asm-generic/no-io.h to provide an "unimplemented" version of those interfaces. Anyway, for this series: Acked-by: Robin Murphy Thanks, Robin. > This series is against my current local tree, which has a few more > "depends on HAS_DMA" than upstream. Of course I will rebase, and split > the last patch per subsystem, if this RFC is welcomed positively. > > Compile-tested with allmodconfig and allyesconfig for m68k/sun3. > > Thanks for your comments! > > Geert Uytterhoeven (6): > [RFC] dma-mapping: Convert NO_DMA get_dma_ops() into a real dummy > [RFC] dma-coherent: Add NO_DMA dummies for managed DMA API > [RFC] usb: gadget: Add NO_DMA dummies for DMA mapping API > [RFC] mm: Add NO_DMA dummies for DMA pool API > [RFC] scsi: Add NO_DMA dummies for SCSI DMA mapping API > [RFC] Treewide: Remove depends on HAS_DMA in case of platform > dependency > > drivers/ata/Kconfig | 2 -- > drivers/crypto/Kconfig | 14 +++------ > drivers/firewire/Kconfig | 1 - > drivers/fpga/Kconfig | 1 - > drivers/gpu/ipu-v3/Kconfig | 1 - > drivers/i2c/busses/Kconfig | 3 -- > drivers/iio/adc/Kconfig | 3 -- > drivers/iommu/Kconfig | 5 ++-- > drivers/lightnvm/Kconfig | 2 +- > drivers/mailbox/Kconfig | 2 -- > drivers/media/pci/dt3155/Kconfig | 1 - > drivers/media/pci/solo6x10/Kconfig | 1 - > drivers/media/pci/sta2x11/Kconfig | 1 - > drivers/media/pci/tw5864/Kconfig | 1 - > drivers/media/pci/tw686x/Kconfig | 1 - > drivers/media/platform/Kconfig | 40 ++++++++----------------- > drivers/media/platform/am437x/Kconfig | 2 +- > drivers/media/platform/atmel/Kconfig | 4 +-- > drivers/media/platform/blackfin/Kconfig | 1 - > drivers/media/platform/davinci/Kconfig | 6 ---- > drivers/media/platform/marvell-ccic/Kconfig | 3 +- > drivers/media/platform/rcar-vin/Kconfig | 2 +- > drivers/media/platform/soc_camera/Kconfig | 3 +- > drivers/media/platform/sti/c8sectpfe/Kconfig | 2 +- > drivers/mmc/host/Kconfig | 10 ++----- > drivers/mtd/nand/Kconfig | 8 ++--- > drivers/mtd/spi-nor/Kconfig | 2 +- > drivers/net/ethernet/amd/Kconfig | 2 +- > drivers/net/ethernet/apm/xgene-v2/Kconfig | 1 - > drivers/net/ethernet/apm/xgene/Kconfig | 1 - > drivers/net/ethernet/arc/Kconfig | 6 ++-- > drivers/net/ethernet/broadcom/Kconfig | 2 -- > drivers/net/ethernet/calxeda/Kconfig | 2 +- > drivers/net/ethernet/hisilicon/Kconfig | 2 +- > drivers/net/ethernet/marvell/Kconfig | 8 ++--- > drivers/net/ethernet/mellanox/mlxsw/Kconfig | 2 +- > drivers/net/ethernet/renesas/Kconfig | 2 -- > drivers/net/ethernet/socionext/Kconfig | 4 +-- > drivers/net/wireless/broadcom/brcm80211/Kconfig | 1 - > drivers/net/wireless/quantenna/qtnfmac/Kconfig | 2 +- > drivers/remoteproc/Kconfig | 1 - > drivers/scsi/hisi_sas/Kconfig | 2 +- > drivers/spi/Kconfig | 12 ++------ > drivers/staging/media/davinci_vpfe/Kconfig | 1 - > drivers/staging/media/omap4iss/Kconfig | 1 - > drivers/staging/vc04_services/Kconfig | 1 - > drivers/tty/serial/Kconfig | 4 --- > drivers/usb/gadget/udc/Kconfig | 4 +-- > drivers/usb/mtu3/Kconfig | 2 +- > drivers/video/fbdev/Kconfig | 3 +- > include/linux/dma-mapping.h | 19 ++++++++---- > include/linux/dmapool.h | 21 +++++++++++-- > include/linux/usb/gadget.h | 12 ++++++++ > include/scsi/scsi_cmnd.h | 5 ++++ > sound/soc/bcm/Kconfig | 3 +- > sound/soc/kirkwood/Kconfig | 1 - > sound/soc/pxa/Kconfig | 1 - > sound/soc/qcom/Kconfig | 6 ++-- > 58 files changed, 108 insertions(+), 148 deletions(-) >