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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D0F80106ACCF for ; Thu, 12 Mar 2026 16:47:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 201F16B008A; Thu, 12 Mar 2026 12:47:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1E3C76B008C; Thu, 12 Mar 2026 12:47:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 110EB6B0092; Thu, 12 Mar 2026 12:47:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 00BA66B008A for ; Thu, 12 Mar 2026 12:47:53 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 970841C393 for ; Thu, 12 Mar 2026 16:47:53 +0000 (UTC) X-FDA: 84537992826.11.29D8117 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf04.hostedemail.com (Postfix) with ESMTP id DA5054000C for ; Thu, 12 Mar 2026 16:47:51 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Sk2jgHEx; spf=pass (imf04.hostedemail.com: domain of leon@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=leon@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1773334072; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=n5rcVNrIGFHHabNrtksNEJRyhpjC7StOpagdUtZ5YEE=; b=fr7eWgm8J2IIIZzZUx7Lgb0xCI9a46+NShm61aQCdvgHzI1FA38d611FrY6doVw6/NEe/n 0CNhzIn916llKKAG5INXwcNu+egm9MheKIwFAzuXGI4XE0IOmrov8HhEf+4wzG3EidVV4B J0a2qtiO+/cpX//jgsQXZyG4H3j4QR4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1773334072; a=rsa-sha256; cv=none; b=SrRulnIiqqU1edjLL7SY+jBwqBjOfSOI8yR03SClDgleLUzSx73nu5rnDCuJtgHfu76r8R ltPeBAylZsdj+hg1eLYwfhrn/LiiC8gb+gFxfzAuXE7tqeC4GIUtVh96gpY132R81DGUJJ gxtehgxbFCL8jfO0/HWxX/oW+kkIPqE= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Sk2jgHEx; spf=pass (imf04.hostedemail.com: domain of leon@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=leon@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id D5F2E4403D; Thu, 12 Mar 2026 16:47:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A4EEC4CEF7; Thu, 12 Mar 2026 16:47:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773334070; bh=bgaeZYcsitfVCRSp3Rb+I23Wjj9WuTcz7df8k9CxCU0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Sk2jgHEx9bowGHuBUzaTSIxN6dUlkVZ5hiKf7nbs7hz2diGk+BqZlhbT3RVHASW+t Chek9Pxn+aNegRCgrWLKCc41aGJFNL429DoAlqDkqrfAksE8bx8qjVtW8qPl/E9554 fL5fjcd2PTMR53v0L6TdvU2THoyhfWVUwsHZx0z557SH71dZ32MbJ2/ROUh1+f43Mw y2hPlFqV7pRvRCga0doEN8wd1K3aoRv147GHVkDLPuW/0DGR3VKjHMbdgaQXZ1IcBb 9xrq+LkDTQ+VuDVm22x3MJM+kg1e5RtiEnHVaUwye0odgqLVuMwo08x+iJeBE7/abI +kiyEnpHUEX8A== Date: Thu, 12 Mar 2026 18:47:47 +0200 From: Leon Romanovsky To: Jason Gunthorpe Cc: Marek Szyprowski , Robin Murphy , "Michael S. Tsirkin" , Petr Tesarik , Jonathan Corbet , Shuah Khan , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Joerg Roedel , Will Deacon , Andrew Morton , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, virtualization@lists.linux.dev, linux-rdma@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 5/8] dma-direct: prevent SWIOTLB path when DMA_ATTR_REQUIRE_COHERENT is set Message-ID: <20260312164747.GA12611@unreal> References: <20260311-dma-debug-overlap-v2-0-e00bc2ca346d@nvidia.com> <20260311-dma-debug-overlap-v2-5-e00bc2ca346d@nvidia.com> <20260312122058.GE1469476@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260312122058.GE1469476@ziepe.ca> X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: DA5054000C X-Stat-Signature: 88m89c6auhc3oehuxd1quti4n4d7o98q X-HE-Tag: 1773334071-987493 X-HE-Meta: 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 +tIUTz5K ax2kVlMIGoY+i6L2fRf4h+E9iwFOiHzNQa8ltxtbjZD+4f3nYR/j1TRoHxXP760MnlY2Sv7/46MQbwTnw6lZW4PFCfrL/caQZ/a1QIyDQC3wQ4xOWJuefKc6foO415PX0v7+BU7Xo1IQvaFyK1yrpC0AKfSpaqGh9m7m3+okz7qLOz/WEuKxxLb1nOPu/EoVqXCSdcwjPJtJnLtr0IuQ6TxybovhUwXcrNMX6vpXsHOLf2GSScBXfUT0JJne9AVanCMmBXlEA1ZMU1D9c+MyFE9Q4H8cBPEE4RVl8qjhy33MCLZ/+pesJzFxyHdss8cC+DDT3 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 12, 2026 at 09:20:58AM -0300, Jason Gunthorpe wrote: > On Wed, Mar 11, 2026 at 09:08:48PM +0200, Leon Romanovsky wrote: > > From: Leon Romanovsky > > > > DMA_ATTR_REQUIRE_COHERENT indicates that SWIOTLB must not be used. > > Ensure the SWIOTLB path is declined whenever the DMA direct path is > > selected. > > > > Signed-off-by: Leon Romanovsky > > --- > > kernel/dma/direct.h | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h > > index e89f175e9c2d0..6184ff303f080 100644 > > --- a/kernel/dma/direct.h > > +++ b/kernel/dma/direct.h > > @@ -84,7 +84,7 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev, > > dma_addr_t dma_addr; > > > > if (is_swiotlb_force_bounce(dev)) { > > - if (attrs & DMA_ATTR_MMIO) > > + if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT)) > > return DMA_MAPPING_ERROR; > > > > return swiotlb_map(dev, phys, size, dir, attrs); > > Oh here it is, still maybe it is better to put it in swiotlb_map() ? It is better do not call function which is not going to work. We have same flow for DMA_ATTR_REQUIRE_COHERENT and DMA_ATTR_MMIO, which both don't work with SWIOTLB. Thanks > > Jason >