From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83CCD25776; Mon, 14 Apr 2025 05:55:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744610105; cv=none; b=NkVYC6aMx4ehej2eH8im9HqUZfXd5fSjU8Ag/AW6pSlQsfWN46vq04ZcwgdkIVShEPbr1yybyM5IIaUB8nKvd53Z1qqQ9K9MxAGpezEI/eY2J/VNkqQ+gNKX7RpC15yWxm/mTZxDdiRzbk1N/KchYEbRF3fqpjuVv+8TFbdGH+4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744610105; c=relaxed/simple; bh=Twf51frDL1JgECgIjkhofiy9l7pFeDlWuBWZG0A6w00=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TI+tBDsRMi/j4IE/4wZTMLdr12IvDowYaGr1hi/ddwVSJsvmRNyNuPTSYv+r1Es7brlkWBzcYnAmykt0lLC/ilbvoIP+dQdDeoWk9sGulwPXyvtO/BdJKxsIG7ropisGoUxhpBOWYyQUGw97Qdlu/6vidBTISGi2TNLvoBNglXE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=I8KfdBzl; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="I8KfdBzl" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ThCKDRswempuOEJ84yo2mtU9l4yxvOGeZE8tpO0fpn4=; b=I8KfdBzlRA2N9nmXn+STRIjztw 2+LGoe/I754+SGvknv8AkTj4J3+46jJ89atsgpbyhLPLRKCwIkQkHkK8x1oiaGMmwVYgtgeaI/Yad V0Fc7vx+6DT3abW+WLCZGC4V82XGjT2VZPHOwz4Zv2UgLPRWgysoSC3j7+xuf1jo3vxN6aqcXmen0 0f+GApbMTtVUVG6rUxjfUFq1ilH/d7lGRoTrWo/O9PYM2FPirNXuIq5o68vxqqS3V1N6x8i/ODWDg Hoz31hEt89k+/PMu8U1jAQK6nQBGwiRk05KrDW/szU/+NcBQ9diDOH1iclyGdr2SFsrcAddYXijea pyEzPO8Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4Cmc-00000000kIO-48Kt; Mon, 14 Apr 2025 05:55:02 +0000 Date: Sun, 13 Apr 2025 22:55:02 -0700 From: Christoph Hellwig To: Bastien Curutchet Cc: Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , Greg Kroah-Hartman , Thomas Petazzoni , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] uio/dma-buf: Give UIO users access to DMA addresses. Message-ID: References: <20250410-uio-dma-v1-0-6468ace2c786@bootlin.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250410-uio-dma-v1-0-6468ace2c786@bootlin.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Apr 10, 2025 at 04:53:17PM +0200, Bastien Curutchet wrote: > Hi all, > > Many UIO users performing DMA from their UIO device need to access the > DMA addresses of the allocated buffers. There are out-of-tree drivers > that allow to do it but nothing in the mainline. In which case it does not matter at all for mainline. FYI the proper and safe way to do DMA from userspace is to use vfio/iommufd.