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 61F3FCA1009 for ; Tue, 2 Sep 2025 09:29:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BBE018E000A; Tue, 2 Sep 2025 05:29:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B95768E0003; Tue, 2 Sep 2025 05:29:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD2BF8E000A; Tue, 2 Sep 2025 05:29:30 -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 999048E0003 for ; Tue, 2 Sep 2025 05:29:30 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 53D0A140AB0 for ; Tue, 2 Sep 2025 09:29:30 +0000 (UTC) X-FDA: 83843787300.20.1CC7CE7 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id 873AA180010 for ; Tue, 2 Sep 2025 09:29:28 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=u+YP0LKc; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of leon@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=leon@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756805368; a=rsa-sha256; cv=none; b=dbfPqwnMv5HrN92cqRaYKLrve8+wwQo4FelNnlse1kLVAXlR/L0l5ZPAQ0WVB70Uelae+C fAUhYY2QHuMjVuWVpXRveSBx5/RN5zQrrm0ONH1xsWME8Lh85b7xdoCByn491ClHhod/Av IouDx5BBkF7PRwFkkUpTX/doB8L9mPM= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=u+YP0LKc; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of leon@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=leon@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756805368; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=RUP9TtL1xAhoFb9CaSEK22nm8Sa8vb9894tliSqEP4U=; b=Ja/LGyXE3w5Xsk63EvhFQ76HqwHDheXC+hwJjDFyQcFCg0zUj9WQt7zTxEPTr4kexkDs5X kK+uXTtbQMaTY5bpFpnF7UlVc7BGQXlZ21lzWGbt4WMn063wkQnGHfp/E2/fipL5PLs2xR xsSz6QpaEgUM9gr9s9Hw2O+E6EuXKP4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 6678F43E7E; Tue, 2 Sep 2025 09:29:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 793FEC4CEED; Tue, 2 Sep 2025 09:29:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756805367; bh=DnDVES5Jg8WrIGoMPMfvxV9Wox20mcRcpnotwmcTmTg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=u+YP0LKc7Ca9KSEGyhHI9LWKXOpYxDkmlx+xi/d94i28PXwnbkADYdG/kMj0eiK5B zd/GooYAccyXKqdo2LtN0swNMmhiizGQIgjHrkSZ2IAXK/1jBPSRk3StbcZycbdrVP g5quZtmGQMVEWVOV9clnOLPmMIcFNqak1dVeFhnzWaY1VIAyIlM9TCnw1bUSOb10fT eYPBFQEGyOkOZzS7K5YPtS3dmkawe2LLvJU33SWPAwVjDdMQDDLsS8LD6Qfe4rZdHI wki/IP/V+av0oWZTHcazqMPHDSPlXAIhw9qhWxKa10uhggFEbKZZEF+GYaHO+zcGYb 634HFrNZvr1dg== Date: Tue, 2 Sep 2025 12:29:20 +0300 From: Leon Romanovsky To: Jason Gunthorpe , Marek Szyprowski Cc: Abdiel Janulgue , Alexander Potapenko , Alex Gaynor , Andrew Morton , Christoph Hellwig , Danilo Krummrich , iommu@lists.linux.dev, Jason Wang , Jens Axboe , Joerg Roedel , Jonathan Corbet , Juergen Gross , kasan-dev@googlegroups.com, Keith Busch , linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvme@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-trace-kernel@vger.kernel.org, Madhavan Srinivasan , Masami Hiramatsu , Michael Ellerman , "Michael S. Tsirkin" , Miguel Ojeda , Robin Murphy , rust-for-linux@vger.kernel.org, Sagi Grimberg , Stefano Stabellini , Steven Rostedt , virtualization@lists.linux.dev, Will Deacon , xen-devel@lists.xenproject.org Subject: Re: [PATCH v4 00/16] dma-mapping: migrate to physical address-based API Message-ID: <20250902092920.GE10073@unreal> References: <20250828115729.GA10073@unreal> <26bd901a-0812-492d-9736-4a7bb2e6d6b4@samsung.com> <20250901222302.GA186519@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250901222302.GA186519@nvidia.com> X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 873AA180010 X-Stat-Signature: 9edua8dw84qzbkt3tw6n44ay6s8pi7qf X-HE-Tag: 1756805368-111420 X-HE-Meta: U2FsdGVkX1+QDwCKd8wlgc8RDq1aga21SiWPf7leh8h9aWLdCRM84wFzTPzWRDQopjiwSccMnwaEQ1CrfmgK0BI6/K7jMTvMiqdkz133X1wCjK7slemHsY2nyZHA5JalMkNHhflOQ1ydE9e2CBdKPlf1n3xM17nMouew+y9RUZZfoI1nDMsKnVjBaGtxZQ9K9DTBULdw5fwk/PBmdLQjm+zh4n0fX6uKK+CVWQJZXYKNTxO2+Xi3Gl8ShWdu5vUz7l3SYGShrnABIUs+y9SJNRoIp3MGyR3GJo8U5UdSE4h7wYb11v3OUTLpouxHT3BF3ms0/IZAM8cC9H+DouhvEDfJHHU64tgYuTqMLv5T0ihwfDTplp1DhiXNedTEp3cCbHD6a3RUAzPSlP1P16VVjHxabhYcwVSiimN/sendvMI3fuUHlKWgwQdQNGIhslEJQ22B2x7nt4GelMs7JpxfgWT0hJqqUNhYuxrvbmNX5UcjiDfBBBL4RXRvG/nC2ehKGVmFhaojcRVBHNR3n5oThW5zxBEWnp3JoXadUSCgpErFSc6OvykMay8+NxOwZhOBVI1MMcB7BADlZ8vJl59VYIKUA3NjFoPwdhtjGkBkFT/KS5uxcg2hBJZVtf4S/E5N/G34IWMo5vKaZdt087LoG2P+x6zhlGx1yyIzdOseH1bUlfdXy5sqX63oNQQ4H68T++fG/w5kU5zQZa+lURnJVRrSp6becV46dLyBKje5VFkLiJNK4n/+2toTbEkVsRQLEZRr5yS3cN12fi5osoRSez8iq8mvJ0/Xr3fuAoXbwlgk3yBoXBPeHEstbw3vEuWukUqUJN0Fo25LczBSCtzfUZw6XwCly1rGVFqAAfU7tusCovVyRAHQiXe+DT+lKwMJ+7R0YA7IZ8kpHz/VVkYetCKKf/ZcwUd9klzDF6G9Z+priEath8hL9IBNL0k8/ngJWezS7+BZ1tcv8faouSw liFwtM16 6u7MlCTsr34ikscd6ueWdYK8JWBBwU/ZBNpKW+JktH3it3xu7sTlApmUGaj8xM14v2OuqYf6Tbo4jy0PCKQLP6v1QLcYyKmp21Hb9+rLHDfdqNRNrzsOBKzU4XpZx4QStJXkLFUfx2uw6Ythwwf8Xl4ZGkY3YuaHV57EsWxaMvtij5upb9fGowdNZqgPXNnsp5LxmhYaUMWNWSGb5JXh6FwrnuZCRgXwY3LxtYM8eyV9DV1/8aElhIL7hQL+w8y8LB+6f5P92ptL9RfqmrXNbUVdkl/y6HtiaD6GYLRrsHlF2NQbXHMAaWsHF8jTVrTPdPDB0ebX+251gPep0jiz64wKF03vBcbdGCuRvnu+zQN4XoWahvK33+w1SVw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Sep 01, 2025 at 07:23:02PM -0300, Jason Gunthorpe wrote: > On Mon, Sep 01, 2025 at 11:47:59PM +0200, Marek Szyprowski wrote: > > I would like to give those patches a try in linux-next, but in meantime > > I tested it on my test farm and found a regression in dma_map_resource() > > handling. Namely the dma_map_resource() is no longer possible with size > > not aligned to kmalloc()'ed buffer, as dma_direct_map_phys() calls > > dma_kmalloc_needs_bounce(), > > Hmm, it's this bit: > > capable = dma_capable(dev, dma_addr, size, !(attrs & DMA_ATTR_MMIO)); > if (unlikely(!capable) || dma_kmalloc_needs_bounce(dev, size, dir)) { > if (is_swiotlb_active(dev) && !(attrs & DMA_ATTR_MMIO)) > return swiotlb_map(dev, phys, size, dir, attrs); > > goto err_overflow; > } > > We shouldn't be checking dma_kmalloc_needs_bounce() on mmio as there > is no cache flushing so the "dma safe alignment" for non-coherent DMA > does not apply. > > Like you say looks good to me, and more of the surrouding code can be > pulled in too, no sense in repeating the boolean logic: > > if (attrs & DMA_ATTR_MMIO) { > dma_addr = phys; > if (unlikely(!dma_capable(dev, dma_addr, size, false))) > goto err_overflow; > } else { > dma_addr = phys_to_dma(dev, phys); > if (unlikely(!dma_capable(dev, dma_addr, size, true)) || I tried to reuse same code as much as possible :( > dma_kmalloc_needs_bounce(dev, size, dir)) { > if (is_swiotlb_active(dev)) > return swiotlb_map(dev, phys, size, dir, attrs); > > goto err_overflow; > } > if (!dev_is_dma_coherent(dev) && > !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) > arch_sync_dma_for_device(phys, size, dir); > } Like Jason wrote, but in diff format: diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index 92dbadcd3b2f..3f4792910604 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -85,7 +85,6 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev, unsigned long attrs) { dma_addr_t dma_addr; - bool capable; if (is_swiotlb_force_bounce(dev)) { if (attrs & DMA_ATTR_MMIO) @@ -94,17 +93,19 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev, return swiotlb_map(dev, phys, size, dir, attrs); } - if (attrs & DMA_ATTR_MMIO) + if (attrs & DMA_ATTR_MMIO) { dma_addr = phys; - else + if (unlikely(dma_capable(dev, dma_addr, size, false))) + goto err_overflow; + } else { dma_addr = phys_to_dma(dev, phys); + if (unlikely(!dma_capable(dev, dma_addr, size, true)) || + dma_kmalloc_needs_bounce(dev, size, dir)) { + if (is_swiotlb_active(dev)) + return swiotlb_map(dev, phys, size, dir, attrs); - capable = dma_capable(dev, dma_addr, size, !(attrs & DMA_ATTR_MMIO)); - if (unlikely(!capable) || dma_kmalloc_needs_bounce(dev, size, dir)) { - if (is_swiotlb_active(dev) && !(attrs & DMA_ATTR_MMIO)) - return swiotlb_map(dev, phys, size, dir, attrs); - - goto err_overflow; + goto err_overflow; + } } if (!dev_is_dma_coherent(dev) && I created new tag with fixed code. https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/tag/?h=dma-phys-Sep-2 Thanks > > Jason