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[195.135.220.15]) by mx.google.com with ESMTPS id gq12si20425835ejb.170.2019.07.31.08.48.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 31 Jul 2019 08:48:11 -0700 (PDT) Received-SPF: pass (google.com: domain of nsaenzjulienne@suse.de designates 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=pass (google.com: domain of nsaenzjulienne@suse.de designates 195.135.220.15 as permitted sender) smtp.mailfrom=nsaenzjulienne@suse.de X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 1CBAEB05E; Wed, 31 Jul 2019 15:48:11 +0000 (UTC) From: Nicolas Saenz Julienne To: catalin.marinas@arm.com, hch@lst.de, wahrenst@gmx.net, marc.zyngier@arm.com, Robin Murphy , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, iommu@lists.linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: phill@raspberryi.org, f.fainelli@gmail.com, will@kernel.org, robh+dt@kernel.org, eric@anholt.net, mbrugger@suse.com, nsaenzjulienne@suse.de, akpm@linux-foundation.org, frowand.list@gmail.com, m.szyprowski@samsung.com, linux-rpi-kernel@lists.infradead.org Subject: [PATCH 8/8] mm: comment arm64's usage of 'enum zone_type' Date: Wed, 31 Jul 2019 17:47:51 +0200 Message-Id: <20190731154752.16557-9-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190731154752.16557-1-nsaenzjulienne@suse.de> References: <20190731154752.16557-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 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: X-Virus-Scanned: ClamAV using ClamSMTP arm64 uses both ZONE_DMA and ZONE_DMA32 for the same reasons x86_64 does: peripherals with different DMA addressing limitations. This updates both ZONE_DMAs comments to inform about the usage. Signed-off-by: Nicolas Saenz Julienne --- include/linux/mmzone.h | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index d77d717c620c..8fa6bcf72e7c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -365,23 +365,24 @@ enum zone_type { * * Some examples * - * Architecture Limit - * --------------------------- - * parisc, ia64, sparc <4G - * s390, powerpc <2G - * arm Various - * alpha Unlimited or 0-16MB. + * Architecture Limit + * ---------------------------------- + * parisc, ia64, sparc, arm64 <4G + * s390, powerpc <2G + * arm Various + * alpha Unlimited or 0-16MB. * * i386, x86_64 and multiple other arches - * <16M. + * <16M. */ ZONE_DMA, #endif #ifdef CONFIG_ZONE_DMA32 /* - * x86_64 needs two ZONE_DMAs because it supports devices that are - * only able to do DMA to the lower 16M but also 32 bit devices that - * can only do DMA areas below 4G. + * x86_64 and arm64 need two ZONE_DMAs because they support devices + * that are only able to DMA a fraction of the 32 bit addressable + * memory area, but also devices that are limited to that whole 32 bit + * area. */ ZONE_DMA32, #endif