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 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.lore.kernel.org (Postfix) with ESMTPS id DD1A7CD5BA4 for ; Thu, 21 May 2026 11:54:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=AfaRmOFwq9PG0Q9lB7Y5h4Js0tCrSyooaZYJ9TAjF4I=; b=hZzVJtYUtSkIci7U/xly5DM5o4 1TN1JmnNIxqm0r48ea44o5bB1sGv/qPFx+DJ2JNnVPLcPQ4NHnZfG7hnAWlL9rNxjd2ytj6yy3zEm fI9tO8eDxRd5mN2vcsKU6nxrjVX1KJnIV+K/G5svsgCR0PvrlUeEgBl7z4HdWttoLM8xCKSdfq6AY 5buA1loAsxHzqjkc5FMplLqYc215FHD1ZyH68lWoBd7JF73rNLp1UfDua3mo+6OaV8onfCHmuDhWi H+eJjU2pjXnwSO0PL4Ig14/54UBSx/rU6JATra0PWg5FA1ol8OMo8aCdSq1nzDkDmA2/xSUKYzSYp Ru4fk04A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQ1yt-00000007ewi-3kvi; Thu, 21 May 2026 11:54:27 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQ1yp-00000007ew2-26B6 for linux-arm-kernel@lists.infradead.org; Thu, 21 May 2026 11:54:26 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 5740A437CB; Thu, 21 May 2026 11:54:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D60901F000E9; Thu, 21 May 2026 11:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779364462; bh=AfaRmOFwq9PG0Q9lB7Y5h4Js0tCrSyooaZYJ9TAjF4I=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=VRoV8Obk6Db2yTrA5yAdD7bmtQFvSWYfd/ZMw0E5GBL5jIdP8p2frzgVjebJ/AI8N hR/ltXnLmqYytDDOSL4NfrAm8WWL6Eapslk7nKLHkiEPTsINTDc/s/wXE5nhOEOkw0 ocFPhIherbIJmWmA0TT9aOS8dxo5zor2QipnNUscdwsm508C2EjBqUXMBblgS8bTHy VTwtO3pIzg195ryyporAX+AUffxjuJV03eR50aV96prxY5h11jwtvbWjHvTe3DepXz Q2BR9ERr09ummMuYbcfqyARU4HAkb3n2S7jWp660Rin4hD/1ttPs8n0zhk15N2/FrI IAG1as/hVnwgg== X-Mailer: emacs 30.2 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev Cc: Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun , linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , x86@kernel.org Subject: Re: [PATCH v4 13/13] x86/amd-gart: preserve the direct DMA address until GART mapping succeeds In-Reply-To: <20260512090408.794195-14-aneesh.kumar@kernel.org> References: <20260512090408.794195-1-aneesh.kumar@kernel.org> <20260512090408.794195-14-aneesh.kumar@kernel.org> Date: Thu, 21 May 2026 17:24:07 +0530 Message-ID: MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260521_045423_576521_9026E107 X-CRM114-Status: GOOD ( 16.62 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org "Aneesh Kumar K.V (Arm)" writes: > gart_alloc_coherent() first allocates memory through dma_direct_alloc(), > which returns a direct-mapped DMA address in dma_addr. When force_iommu is > enabled, the buffer is then remapped. > > Do not overwrite dma_addr before dma_map_area() has succeeded. Keep the > dma_map_area result in a temporary variable so the direct DMA address > remains available for dma_direct_free() on the error path. > > Signed-off-by: Aneesh Kumar K.V (Arm) > --- > arch/x86/kernel/amd_gart_64.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c > index b5f1f031d45b..a109649c5649 100644 > --- a/arch/x86/kernel/amd_gart_64.c > +++ b/arch/x86/kernel/amd_gart_64.c > @@ -467,18 +467,20 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr, > gfp_t flag, unsigned long attrs) > { > void *vaddr; > + dma_addr_t dma_map_addr; > > vaddr = dma_direct_alloc(dev, size, dma_addr, flag, attrs); > if (!vaddr || > !force_iommu || dev->coherent_dma_mask <= DMA_BIT_MASK(24)) > return vaddr; > > - *dma_addr = dma_map_area(dev, virt_to_phys(vaddr), size, > - DMA_BIDIRECTIONAL, > - (1UL << get_order(size)) - 1, attrs); > + dma_map_addr = dma_map_area(dev, virt_to_phys(vaddr), size, > + DMA_BIDIRECTIONAL, > + (1UL << get_order(size)) - 1, attrs); > flush_gart(); > - if (unlikely(*dma_addr == DMA_MAPPING_ERROR)) > + if (unlikely(dma_map_addr == DMA_MAPPING_ERROR)) > goto out_free; > + *dma_addr = dma_map_addr; > return vaddr; > out_free: > dma_direct_free(dev, size, vaddr, *dma_addr, attrs); > -- > 2.43.0 > This needs corresponding changes on the gart_free_coherent() side as well. https://sashiko.dev/#/patchset/20260512090408.794195-1-aneesh.kumar%40kernel.org?part=13 I will avoid making that change as part of this series, since I assume it would require specific testing. -aneesh