From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033745AbeCARtt (ORCPT ); Thu, 1 Mar 2018 12:49:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:48458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033501AbeCARtp (ORCPT ); Thu, 1 Mar 2018 12:49:45 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F7F020856 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=helgaas@kernel.org Date: Thu, 1 Mar 2018 11:49:41 -0600 From: Bjorn Helgaas To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-block@vger.kernel.org, Stephen Bates , Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?iso-8859-1?B?Suly9G1l?= Glisse , Benjamin Herrenschmidt , Alex Williamson Subject: Re: [PATCH v2 03/10] PCI/P2PDMA: Add PCI p2pmem dma mappings to adjust the bus offset Message-ID: <20180301174941.GG13722@bhelgaas-glaptop.roam.corp.google.com> References: <20180228234006.21093-1-logang@deltatee.com> <20180228234006.21093-4-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180228234006.21093-4-logang@deltatee.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 28, 2018 at 04:39:59PM -0700, Logan Gunthorpe wrote: > The DMA address used when mapping PCI P2P memory must be the PCI bus > address. Thus, introduce pci_p2pmem_[un]map_sg() to map the correct > addresses when using P2P memory. > > For this, we assume that an SGL passed to these functions contain all > p2p memory or no p2p memory. > > Signed-off-by: Logan Gunthorpe > --- > drivers/pci/p2pdma.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/memremap.h | 1 + > include/linux/pci-p2pdma.h | 13 ++++++++++++ > 3 files changed, 65 insertions(+) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index a57df78f6a32..4e1c81f64b29 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -188,6 +188,8 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, > pgmap->res.flags = pci_resource_flags(pdev, bar); > pgmap->ref = &pdev->p2pdma->devmap_ref; > pgmap->type = MEMORY_DEVICE_PCI_P2PDMA; > + pgmap->pci_p2pdma_bus_offset = pci_bus_address(pdev, bar) - > + pci_resource_start(pdev, bar); > > addr = devm_memremap_pages(&pdev->dev, pgmap); > if (IS_ERR(addr)) > @@ -616,3 +618,52 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) > pdev->p2pdma->published = publish; > } > EXPORT_SYMBOL_GPL(pci_p2pmem_publish); > + > +/* > + * pci_p2pdma_map_sg - map a PCI peer-to-peer sg for DMA > + * @dev: device doing the DMA request > + * @sg: scatter list to map > + * @nents: elements in the scatterlist > + * @dir: DMA direction Can you fix these so the descriptions all have a single space after the "@dev:", which seems to be the existing convention in this file? The indentation looks pretty random now. > + * > + * Returns the number of SG entries mapped > + */ > +int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, > + enum dma_data_direction dir) Same question as before about why the mixture of "pci_*" interfaces that take "struct device *" parameters. > +{ > + struct dev_pagemap *pgmap; > + struct scatterlist *s; > + phys_addr_t paddr; > + int i; > + > + /* > + * p2pdma mappings are not compatible with devices that use > + * dma_virt_ops. > + */ > + if (IS_ENABLED(CONFIG_DMA_VIRT_OPS) && dev->dma_ops == &dma_virt_ops) > + return 0; > + > + for_each_sg(sg, s, nents, i) { > + pgmap = sg_page(s)->pgmap; > + paddr = sg_phys(s); > + > + s->dma_address = paddr - pgmap->pci_p2pdma_bus_offset; > + sg_dma_len(s) = s->length; > + } > + > + return nents; > +} > +EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg); > + > +/** > + * pci_p2pdma_unmap_sg - unmap a PCI peer-to-peer sg for DMA > + * @dev: device doing the DMA request > + * @sg: scatter list to map > + * @nents: elements in the scatterlist > + * @dir: DMA direction Same whitespace comment as above. > + */ > +void pci_p2pdma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, > + enum dma_data_direction dir) > +{ > +} > +EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg); > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 9e907c338a44..1660f64ce96f 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -125,6 +125,7 @@ struct dev_pagemap { > struct device *dev; > void *data; > enum memory_type type; > + u64 pci_p2pdma_bus_offset; > }; > > #ifdef CONFIG_ZONE_DEVICE > diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h > index c0dde3d3aac4..126eca697ab3 100644 > --- a/include/linux/pci-p2pdma.h > +++ b/include/linux/pci-p2pdma.h > @@ -36,6 +36,10 @@ int pci_p2pmem_alloc_sgl(struct pci_dev *pdev, struct scatterlist **sgl, > void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl, > unsigned int nents); > void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); > +int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, > + enum dma_data_direction dir); > +void pci_p2pdma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, > + enum dma_data_direction dir); > #else /* CONFIG_PCI_P2PDMA */ > static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, > size_t size, u64 offset) > @@ -83,5 +87,14 @@ static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev, > static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) > { > } > +static inline int pci_p2pdma_map_sg(struct device *dev, > + struct scatterlist *sg, int nents, enum dma_data_direction dir) > +{ > + return 0; > +} > +static inline void pci_p2pdma_unmap_sg(struct device *dev, > + struct scatterlist *sg, int nents, enum dma_data_direction dir) > +{ > +} > #endif /* CONFIG_PCI_P2PDMA */ > #endif /* _LINUX_PCI_P2P_H */ > -- > 2.11.0 >