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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 959F0C4332F for ; Mon, 27 Sep 2021 18:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 778AF60E09 for ; Mon, 27 Sep 2021 18:46:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236357AbhI0Ssa (ORCPT ); Mon, 27 Sep 2021 14:48:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:59164 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234211AbhI0Ss2 (ORCPT ); Mon, 27 Sep 2021 14:48:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 351AC60F70; Mon, 27 Sep 2021 18:46:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632768410; bh=aAUpJLAvxQ+tHaQKvkiHUoC8zvr3SDhJ8uiCDNoeqXs=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=qzynkof5Gd1zNVPHo3jVrAnP115kuAFhtBukKFpONdjp87NprCm91HDbrE/owxdhZ xxo+KOoGVV8xi+r/xixAGATY/mdBwwFHbvwyMTntL/h4E9NIije4CwzKImO+Ft2TkT esRYtMPRx+sjIdI+yAhG+ZMuViJGWjFRbn/mUsDAUOmzw+aAGycJPSGKcxVsrEIzp8 X0mn6JIfspomXpax77aqWhehi+1mnH/vQ4jhS6hEKe6Mz0SIuDNSMiJKjScDPZ41Nq qTUq0ayObtqPUirRQM9z42nmYatHl4UCiTIAydz4MMVW/EurQNGzuSW/wTRFFDwp+A k19lzCPqTmXVQ== Date: Mon, 27 Sep 2021 13:46:48 -0500 From: Bjorn Helgaas To: Logan 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 , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni Subject: Re: [PATCH v3 03/20] PCI/P2PDMA: make pci_p2pdma_map_type() non-static Message-ID: <20210927184648.GA667259@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210916234100.122368-4-logang@deltatee.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 16, 2021 at 05:40:43PM -0600, Logan Gunthorpe wrote: > pci_p2pdma_map_type() will be needed by the dma-iommu map_sg > implementation because it will need to determine the mapping type > ahead of actually doing the mapping to create the actual iommu mapping. I don't expect this to go via the PCI tree, but if it did I would silently: s/PCI/P2PDMA: make pci_p2pdma_map_type() non-static/ PCI/P2PDMA: Expose pci_p2pdma_map_type()/ s/iommu/IOMMU/ and mention what this patch does in the commit log (in addition to the subject) and fix a couple minor typos below. > Signed-off-by: Logan Gunthorpe Acked-by: Bjorn Helgaas > --- > drivers/pci/p2pdma.c | 24 +++++++++++++--------- > include/linux/pci-p2pdma.h | 41 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 1192c465ba6d..b656d8c801a7 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -20,13 +20,6 @@ > #include > #include > > -enum pci_p2pdma_map_type { > - PCI_P2PDMA_MAP_UNKNOWN = 0, > - PCI_P2PDMA_MAP_NOT_SUPPORTED, > - PCI_P2PDMA_MAP_BUS_ADDR, > - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, > -}; > - > struct pci_p2pdma { > struct gen_pool *pool; > bool p2pmem_published; > @@ -841,8 +834,21 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) > } > EXPORT_SYMBOL_GPL(pci_p2pmem_publish); > > -static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > - struct device *dev) > +/** > + * pci_p2pdma_map_type - return the type of mapping that should be used for > + * a given device and pgmap > + * @pgmap: the pagemap of a page to determine the mapping type for > + * @dev: device that is mapping the page > + * > + * Returns one of: > + * PCI_P2PDMA_MAP_NOT_SUPPORTED - The mapping should not be done > + * PCI_P2PDMA_MAP_BUS_ADDR - The mapping should use the PCI bus address > + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE - The mapping should be done normally > + * using the CPU physical address (in dma-direct) or an IOVA > + * mapping for the IOMMU. > + */ > +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > + struct device *dev) > { > enum pci_p2pdma_map_type type = PCI_P2PDMA_MAP_NOT_SUPPORTED; > struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; > diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h > index 8318a97c9c61..caac2d023f8f 100644 > --- a/include/linux/pci-p2pdma.h > +++ b/include/linux/pci-p2pdma.h > @@ -16,6 +16,40 @@ > struct block_device; > struct scatterlist; > > +enum pci_p2pdma_map_type { > + /* > + * PCI_P2PDMA_MAP_UNKNOWN: Used internally for indicating the mapping > + * type hasn't been calculated yet. Functions that return this enum > + * never return this value. > + */ > + PCI_P2PDMA_MAP_UNKNOWN = 0, > + > + /* > + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will > + * traverse the host bridge and the host bridge is not in the > + * whitelist. DMA Mapping routines should return an error when > + * this is returned. > + */ > + PCI_P2PDMA_MAP_NOT_SUPPORTED, > + > + /* > + * PCI_P2PDMA_BUS_ADDR: Indicates that two devices can talk to > + * eachother directly through a PCI switch and the transaction will > + * not traverse the host bridge. Such a mapping should program > + * the DMA engine with PCI bus addresses. s/eachother/each other/ > + */ > + PCI_P2PDMA_MAP_BUS_ADDR, > + > + /* > + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk > + * to eachother, but the transaction traverses a host bridge on the > + * whitelist. In this case, a normal mapping either with CPU physical > + * addresses (in the case of dma-direct) or IOVA addresses (in the > + * case of IOMMUs) should be used to program the DMA engine. s/eachother/each other/ > + */ > + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, > +}; > + > #ifdef CONFIG_PCI_P2PDMA > int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, > u64 offset); > @@ -30,6 +64,8 @@ struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev, > unsigned int *nents, u32 length); > void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl); > void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); > +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > + struct device *dev); > int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, > int nents, enum dma_data_direction dir, unsigned long attrs); > void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, > @@ -83,6 +119,11 @@ 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 enum pci_p2pdma_map_type > +pci_p2pdma_map_type(struct dev_pagemap *pgmap, struct device *dev) > +{ > + return PCI_P2PDMA_MAP_NOT_SUPPORTED; > +} > static inline int pci_p2pdma_map_sg_attrs(struct device *dev, > struct scatterlist *sg, int nents, enum dma_data_direction dir, > unsigned long attrs) > -- > 2.30.2 >