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=-12.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 6BAB4C35257 for ; Wed, 16 Sep 2020 06:28:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C6A221D7D for ; Wed, 16 Sep 2020 06:28:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="kaFJQyPG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726281AbgIPG2Q (ORCPT ); Wed, 16 Sep 2020 02:28:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42270 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726140AbgIPG2N (ORCPT ); Wed, 16 Sep 2020 02:28:13 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C234C06174A; Tue, 15 Sep 2020 23:28:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Sj9/6zg3jBvpe8GWBJtfj7ccMtl/cKmotOW4AeELf0k=; b=kaFJQyPGFngO1rYezn8V4WHTVt bifyPF57Tk4KW6ZXJihhjLUmUxhyNOZUK4hogmfIPx4IEGF7HmjMlXwQkKqSoC5DKQpOh5mz2TcwA h9nqDo+Hc9Y9pLTBIuIX5O9eFitiNQINnXhnSwQhAzSOotBpjP7fmuWmPg0Y9ZmrdERGPmzxV+V2b AZ/toz2BrsjHtlWvKHpmxhL+b5NqgTFXzS5c3QQEHrKB9waDNeovto1ihomE50eY44nWiFIVDJO+4 QGH2ncs+/Sp2SIcFzjs2cQ98GYmTPQnEHa8fZDL77q5xqeenvtITFLDMI/+OrdxwONe8RJgfDTcCM 4+kjLiaA==; Received: from 089144214092.atnat0023.highway.a1.net ([89.144.214.92] helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIQvG-0007fh-Mj; Wed, 16 Sep 2020 06:28:07 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org, Russell King , Santosh Shilimkar , Greg Kroah-Hartman Cc: Jim Quinlan , Nathan Chancellor , Florian Fainelli , Robin Murphy , Rob Herring , Frank Rowand , Ohad Ben-Cohen , Bjorn Andersson , linux-remoteproc@vger.kernel.org, linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org Subject: [PATCH 5/6] usb: don't inherity DMA properties for USB devices Date: Wed, 16 Sep 2020 08:14:58 +0200 Message-Id: <20200916061500.1970090-6-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200916061500.1970090-1-hch@lst.de> References: <20200916061500.1970090-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org As the comment in usb_alloc_dev correctly states, drivers can't use the DMA API on usb device, and at least calling dma_set_mask on them is highly dangerous. Unlike what the comment states upper level drivers also can't really use the presence of a dma mask to check for DMA support, as the dma_mask is set by default for most busses. Setting the dma_mask comes from "[PATCH] usbcore dma updates (and doc)" in BitKeeper times, as it seems like it was primarily for setting the NETIF_F_HIGHDMA flag in USB drivers, something that has long been fixed up since. Setting the dma_pfn_offset comes from commit b44bbc46a8bb ("usb: core: setup dma_pfn_offset for USB devices and, interfaces"), which worked around the fact that the scsi_calculate_bounce_limits functions wasn't going through the proper driver interface to query DMA information, but that function was removed in commit 21e07dba9fb1 ("scsi: reduce use of block bounce buffers") years ago. Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman --- drivers/usb/core/message.c | 6 ------ drivers/usb/core/usb.c | 12 ------------ 2 files changed, 18 deletions(-) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 6197938dcc2d8f..9e45732dc1d1d1 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1954,12 +1954,6 @@ int usb_set_configuration(struct usb_device *dev, int configuration) intf->dev.bus = &usb_bus_type; intf->dev.type = &usb_if_device_type; intf->dev.groups = usb_interface_groups; - /* - * Please refer to usb_alloc_dev() to see why we set - * dma_mask and dma_pfn_offset. - */ - intf->dev.dma_mask = dev->dev.dma_mask; - intf->dev.dma_pfn_offset = dev->dev.dma_pfn_offset; INIT_WORK(&intf->reset_ws, __usb_queue_reset_device); intf->minor = -1; device_initialize(&intf->dev); diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index bafc113f2b3ef3..9b4ac4415f1a47 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -599,18 +599,6 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent, dev->dev.bus = &usb_bus_type; dev->dev.type = &usb_device_type; dev->dev.groups = usb_device_groups; - /* - * Fake a dma_mask/offset for the USB device: - * We cannot really use the dma-mapping API (dma_alloc_* and - * dma_map_*) for USB devices but instead need to use - * usb_alloc_coherent and pass data in 'urb's, but some subsystems - * manually look into the mask/offset pair to determine whether - * they need bounce buffers. - * Note: calling dma_set_mask() on a USB device would set the - * mask for the entire HCD, so don't do that. - */ - dev->dev.dma_mask = bus->sysdev->dma_mask; - dev->dev.dma_pfn_offset = bus->sysdev->dma_pfn_offset; set_dev_node(&dev->dev, dev_to_node(bus->sysdev)); dev->state = USB_STATE_ATTACHED; dev->lpm_disable_count = 1; -- 2.28.0