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Fri, 27 May 2022 09:35:15 -0600 Message-ID: Date: Fri, 27 May 2022 09:35:07 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Content-Language: en-CA To: Jason Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , =?UTF-8?Q?Christian_K=c3=b6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni , Ralph Campbell , Bjorn Helgaas References: <20220407154717.7695-1-logang@deltatee.com> <20220407154717.7695-21-logang@deltatee.com> <20220527125501.GD2960187@ziepe.ca> From: Logan Gunthorpe In-Reply-To: <20220527125501.GD2960187@ziepe.ca> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, sbates@raithlin.com, hch@lst.de, dan.j.williams@intel.com, christian.koenig@amd.com, jhubbard@nvidia.com, ddutile@redhat.com, willy@infradead.org, daniel.vetter@ffwll.ch, andrzej.jakowski@intel.com, dave.b.minturn@intel.com, jason@jlekstrand.net, dave.hansen@linux.intel.com, jianxin.xiong@intel.com, helgaas@kernel.org, ira.weiny@intel.com, robin.murphy@arm.com, martin.oliveira@eideticom.com, ckulkarnilinux@gmail.com, rcampbell@nvidia.com, bhelgaas@google.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v6 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem() X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 2B1E1100036 X-Stat-Signature: xohzqt64ryx7fzgeq67ih6mrxkzt6uoo Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=deltatee.com header.s=20200525 header.b=LK0tOmWx; dmarc=pass (policy=none) header.from=deltatee.com; spf=pass (imf14.hostedemail.com: domain of logang@deltatee.com designates 204.191.154.188 as permitted sender) smtp.mailfrom=logang@deltatee.com X-HE-Tag: 1653665718-875881 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: On 2022-05-27 06:55, Jason Gunthorpe wrote: > On Thu, Apr 07, 2022 at 09:47:16AM -0600, Logan Gunthorpe wrote: >> +static void pci_p2pdma_unmap_mappings(void *data) >> +{ >> + struct pci_dev *pdev = data; >> + struct pci_p2pdma *p2pdma = rcu_dereference_protected(pdev->p2pdma, 1); >> + >> + /* Ensure no new pages can be allocated in mappings */ >> + p2pdma->active = false; >> + synchronize_rcu(); >> + >> + unmap_mapping_range(p2pdma->inode->i_mapping, 0, 0, 1); >> + >> + /* >> + * On some architectures, TLB flushes are done with call_rcu() >> + * so to ensure GUP fast is done with the pages, call synchronize_rcu() >> + * before freeing them. >> + */ >> + synchronize_rcu(); >> + pci_p2pdma_free_mappings(p2pdma->inode->i_mapping); > > With the series from Felix getting close this should get updated to > not set pte_devmap and use proper natural refcounting without any of > this stuff. Can you send a link? I'm not sure what you are referring to. Thanks, Logan