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X-CSE-ConnectionGUID: oTI2g/51Soe2Glddd+HPAg== X-CSE-MsgGUID: HZN1SV/EScGO/cdKaCd/wg== X-IronPort-AV: E=McAfee;i="6700,10204,11417"; a="47641264" X-IronPort-AV: E=Sophos;i="6.15,247,1739865600"; d="scan'208";a="47641264" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2025 19:12:58 -0700 X-CSE-ConnectionGUID: PgtT/sVnTcyJIj7GTIKVrA== X-CSE-MsgGUID: VBjHGcPQSj2zSMxum7MGbA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,247,1739865600"; d="scan'208";a="137721801" Received: from allen-sbox.sh.intel.com (HELO [10.239.159.30]) ([10.239.159.30]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2025 19:12:50 -0700 Message-ID: Date: Tue, 29 Apr 2025 10:08:36 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 01/24] PCI/P2PDMA: Refactor the p2pdma mapping helpers To: Leon Romanovsky , Marek Szyprowski , Jens Axboe , Christoph Hellwig , Keith Busch Cc: Jake Edge , Jonathan Corbet , Jason Gunthorpe , Zhu Yanjun , Robin Murphy , Joerg Roedel , Will Deacon , Sagi Grimberg , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Niklas Schnelle , Chuck Lever , Luis Chamberlain , Matthew Wilcox , Dan Williams , Kanchan Joshi , Chaitanya Kulkarni , Leon Romanovsky References: <3ad16e0fc3b8f66593a837c9cdcd34bda1e1ab22.1745831017.git.leon@kernel.org> Content-Language: en-US From: Baolu Lu In-Reply-To: <3ad16e0fc3b8f66593a837c9cdcd34bda1e1ab22.1745831017.git.leon@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/28/25 17:22, Leon Romanovsky wrote: > From: Christoph Hellwig > > The current scheme with a single helper to determine the P2P status > and map a scatterlist segment force users to always use the map_sg > helper to DMA map, which we're trying to get away from because they > are very cache inefficient. > > Refactor the code so that there is a single helper that checks the P2P > state for a page, including the result that it is not a P2P page to > simplify the callers, and a second one to perform the address translation > for a bus mapped P2P transfer that does not depend on the scatterlist > structure. > > Signed-off-by: Christoph Hellwig > Reviewed-by: Logan Gunthorpe > Acked-by: Bjorn Helgaas > Tested-by: Jens Axboe > Reviewed-by: Luis Chamberlain > Signed-off-by: Leon Romanovsky Reviewed-by: Lu Baolu