From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id BF4F721A02937 for ; Mon, 24 Sep 2018 15:39:16 -0700 (PDT) Date: Mon, 24 Sep 2018 17:39:14 -0500 From: Bjorn Helgaas Subject: Re: [PATCH v6 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers Message-ID: <20180924223914.GP224714@bhelgaas-glaptop.roam.corp.google.com> References: <20180913001156.4115-1-logang@deltatee.com> <20180913001156.4115-5-logang@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180913001156.4115-5-logang@deltatee.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Logan Gunthorpe Cc: Jens Axboe , Alex Williamson , linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, =?iso-8859-1?B?Suly9G1l?= Glisse , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , Christoph Hellwig List-ID: On Wed, Sep 12, 2018 at 06:11:47PM -0600, Logan Gunthorpe wrote: > Users of the P2PDMA infrastructure will typically need a way for > the user to tell the kernel to use P2P resources. Typically > this will be a simple on/off boolean operation but sometimes > it may be desirable for the user to specify the exact device to > use for the P2P operation. > > Add new helpers for attributes which take a boolean or a PCI device. > Any boolean, or the word 'auto' turn P2P on or off. Specifying a full > PCI device name/BDF will select the specific device. > > Signed-off-by: Logan Gunthorpe I appreciate your update to drop "auto" and show 0/1/pci_name(). When you post that, include my: Acked-by: Bjorn Helgaas > --- > drivers/pci/p2pdma.c | 83 ++++++++++++++++++++++++++++++++++++++ > include/linux/pci-p2pdma.h | 15 +++++++ > 2 files changed, 98 insertions(+) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 29bd40a87768..3da848f3fe72 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -9,6 +9,7 @@ > */ > > #define pr_fmt(fmt) "pci-p2pdma: " fmt > +#include > #include > #include > #include > @@ -856,3 +857,85 @@ int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, > return nents; > } > EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg); > + > +/** > + * pci_p2pdma_enable_store - parse a configfs/sysfs attribute store > + * to enable p2pdma > + * @page: contents of the value to be stored > + * @p2p_dev: returns the PCI device that was selected to be used > + * (if 'auto', 'none or a boolean isn't the store value) > + * @use_p2pdma: returns whether to enable p2pdma or not > + * > + * Parses an attribute value to decide whether to enable p2pdma. > + * The value can select a PCI device (using it's full BDF device > + * name), a boolean, or 'auto'. 'auto' and a true boolean value > + * have the same meaning. A false value disables p2pdma and > + * a PCI device enables it to use a specific device as the > + * backing provider. > + * > + * pci_p2pdma_enable_show() should be used as the show operation for > + * the attribute. > + * > + * Returns 0 on success > + */ > +int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev, > + bool *use_p2pdma) > +{ > + struct device *dev; > + > + dev = bus_find_device_by_name(&pci_bus_type, NULL, page); > + if (dev) { > + *use_p2pdma = true; > + *p2p_dev = to_pci_dev(dev); > + > + if (!pci_has_p2pmem(*p2p_dev)) { > + pr_err("PCI device has no peer-to-peer memory: %s\n", > + page); > + pci_dev_put(*p2p_dev); > + return -ENODEV; > + } > + > + return 0; > + } else if (sysfs_streq(page, "auto")) { > + *use_p2pdma = true; > + return 0; > + } else if ((page[0] == '0' || page[0] == '1') && !iscntrl(page[1])) { > + /* > + * If the user enters a PCI device that doesn't exist > + * like "0000:01:00.1", we don't want strtobool to think > + * it's a '0' when it's clearly not what the user wanted. > + * So we require 0's and 1's to be exactly one character. > + */ > + } else if (!strtobool(page, use_p2pdma)) { > + return 0; > + } > + > + pr_err("No such PCI device: %.*s\n", (int)strcspn(page, "\n"), page); > + return -ENODEV; > +} > +EXPORT_SYMBOL_GPL(pci_p2pdma_enable_store); > + > +/** > + * pci_p2pdma_enable_show - show a configfs/sysfs attribute indicating > + * whether p2pdma is enabled > + * @page: contents of the stored value > + * @p2p_dev: the selected p2p device (NULL if no device is selected) > + * @use_p2pdma: whether p2pdme has been enabled > + * > + * Attributes that use pci_p2pdma_enable_store() should use this function > + * to show the value of the attribute. > + * > + * Returns 0 on success > + */ > +ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, > + bool use_p2pdma) > +{ > + if (!use_p2pdma) > + return sprintf(page, "none\n"); > + > + if (!p2p_dev) > + return sprintf(page, "auto\n"); > + > + return sprintf(page, "%s\n", pci_name(p2p_dev)); > +} > +EXPORT_SYMBOL_GPL(pci_p2pdma_enable_show); > diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h > index 2f03dbbf5af6..377de4d73767 100644 > --- a/include/linux/pci-p2pdma.h > +++ b/include/linux/pci-p2pdma.h > @@ -38,6 +38,10 @@ void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl); > 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); > +int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev, > + bool *use_p2pdma); > +ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, > + bool use_p2pdma); > #else /* CONFIG_PCI_P2PDMA */ > static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, > size_t size, u64 offset) > @@ -105,5 +109,16 @@ static inline int pci_p2pdma_map_sg(struct device *dev, > { > return 0; > } > +static inline int pci_p2pdma_enable_store(const char *page, > + struct pci_dev **p2p_dev, bool *use_p2pdma) > +{ > + *use_p2pdma = false; > + return 0; > +} > +static inline ssize_t pci_p2pdma_enable_show(char *page, > + struct pci_dev *p2p_dev, bool use_p2pdma) > +{ > + return sprintf(page, "none\n"); > +} > #endif /* CONFIG_PCI_P2PDMA */ > #endif /* _LINUX_PCI_P2P_H */ > -- > 2.19.0 > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm