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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 37E8CC0650F for ; Thu, 8 Aug 2019 16:57:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CB0321874 for ; Thu, 8 Aug 2019 16:57:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="HEtOaayA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404101AbfHHQ5q (ORCPT ); Thu, 8 Aug 2019 12:57:46 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:43560 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728289AbfHHQ5q (ORCPT ); Thu, 8 Aug 2019 12:57:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ED7e8Ih4bHyHDCY/4eqes98RiULX2Mf6sQjwvNk6YLI=; b=HEtOaayAs5z8Q5QJuNZExgI6F +T+yjUP8Hqtm24tikmCLflGGfe9VSn1Z082YkaVMXOWfxFGi8lnoUbE2YaL0km1Z0eWOk4LsVu0Va z9eWLGV4vP5t3FZZi30rn0MFUBtloE91Wfre/vO1Xb3ltF3o1EyMonQVtNC15qYhKpt0pEs2yymm3 Fo7kmZSPxiopdMS2S6w4ZQ6wWC4t2hDKHizKG0Tj2RAC4Gyajo+SqJmr5evxLb46Qscw3pujg9UfB 2f6i04O7odGaoWvSU9jdx65LeNs3ycRg+XFkismkKLvfwxTobZA9soPtRmZTOdpeQn9B5JakiuRYz /1lprmjUQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:54188) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1hvljO-00059I-Tx; Thu, 08 Aug 2019 17:57:39 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1hvljK-0002pQ-7m; Thu, 08 Aug 2019 17:57:34 +0100 Date: Thu, 8 Aug 2019 17:57:34 +0100 From: Russell King - ARM Linux admin To: Christoph Hellwig Cc: yvahkhfo.1df7f8c2@hashmail.org, security@kernel.org, linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: usb zero copy dma handling Message-ID: <20190808165734.GG5193@shell.armlinux.org.uk> References: <20190808084636.GB15080@priv-mua.localdomain> <20190808161015.GA8470@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190808161015.GA8470@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, Aug 08, 2019 at 09:10:15AM -0700, Christoph Hellwig wrote: > On Thu, Aug 08, 2019 at 10:46:36AM +0200, yvahkhfo.1df7f8c2@hashmail.org wrote: > > --- a/drivers/usb/core/devio.c > > +++ b/drivers/usb/core/devio.c > > @@ -238,9 +238,14 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma) > > usbm->vma_use_count = 1; > > INIT_LIST_HEAD(&usbm->memlist); > > > > +#ifdef CONFIG_X86 > > if (remap_pfn_range(vma, vma->vm_start, > > virt_to_phys(usbm->mem) >> PAGE_SHIFT, > > size, vma->vm_page_prot) < 0) { > > +#else /* !CONFIG_X86 */ > > + if (dma_mmap_coherent(ps->dev->bus->sysdev, > > + vma, mem, dma_handle, size) < 0) { > > +#endif /* !CONFIG_X86 */ > > Doing the dma_mmap_coherent unconditionally is the right thing here. So what if usbm->mem is from kmalloc because the host doesn't support DMA? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up