nvdimm.lists.linux.dev archive mirror
 help / color / mirror / Atom feed
From: Logan Gunthorpe <logang@deltatee.com>
To: 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
Cc: "Jens Axboe" <axboe@kernel.dk>,
	"Christian König" <christian.koenig@amd.com>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Jason Gunthorpe" <jgg@mellanox.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Max Gurtovoy" <maxg@mellanox.com>,
	"Christoph Hellwig" <hch@lst.de>
Subject: [PATCH v9 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers
Date: Thu,  4 Oct 2018 15:27:38 -0600	[thread overview]
Message-ID: <20181004212747.6301-5-logang@deltatee.com> (raw)
In-Reply-To: <20181004212747.6301-1-logang@deltatee.com>

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 as accepted by strtobool() turn P2P on or off (such as 'y', 'n',
'1', '0', etc). Specifying a full PCI device name/BDF will select the
specific device.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/p2pdma.c       | 82 ++++++++++++++++++++++++++++++++++++++
 include/linux/pci-p2pdma.h | 15 +++++++
 2 files changed, 97 insertions(+)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index e914f04ea1ec..b18b3703ab79 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -8,6 +8,8 @@
  * Copyright (c) 2018, Eideticom Inc.
  */
 
+#define pr_fmt(fmt) "pci-p2pdma: " fmt
+#include <linux/ctype.h>
 #include <linux/pci-p2pdma.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -725,3 +727,83 @@ 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 one was specified in the stored 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) or a boolean (in any format strtobool() accepts). A false
+ * value disables p2pdma, a true value expects the caller
+ * to automatically find a compatible device and specifying a PCI device
+ * expects the caller to use the specific 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)) {
+			pci_err(*p2p_dev,
+				"PCI device has no peer-to-peer memory: %s\n",
+				page);
+			pci_dev_put(*p2p_dev);
+			return -ENODEV;
+		}
+
+		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, "0\n");
+
+	if (!p2p_dev)
+		return sprintf(page, "1\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 b6dfb6dc2e53..bca9bc3e5be7 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -32,6 +32,10 @@ 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)
@@ -82,6 +86,17 @@ 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 */
 
 
-- 
2.19.0

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

  parent reply	other threads:[~2018-10-04 21:27 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-04 21:27 [PATCH v9 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-10-04 21:27 ` [PATCH v9 01/13] PCI/P2PDMA: Support peer-to-peer memory Logan Gunthorpe
2018-10-04 21:27 ` [PATCH v9 02/13] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-10-05  7:08   ` Christoph Hellwig
2018-10-04 21:27 ` [PATCH v9 03/13] PCI/P2PDMA: Add PCI p2pmem DMA mappings to adjust the bus offset Logan Gunthorpe
2018-10-05  7:08   ` Christoph Hellwig
2018-10-04 21:27 ` Logan Gunthorpe [this message]
2018-10-05  7:08   ` [PATCH v9 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers Christoph Hellwig
2018-10-04 21:27 ` [PATCH v9 05/13] docs-rst: Add a new directory for PCI documentation Logan Gunthorpe
2018-10-04 21:27 ` [PATCH v9 06/13] PCI/P2PDMA: Add P2P DMA driver writer's documentation Logan Gunthorpe
2018-10-04 21:27 ` [PATCH v9 07/13] block: Add PCI P2P flag for request queue and check support for requests Logan Gunthorpe
2018-10-05  7:09   ` Christoph Hellwig
2018-10-06  1:16   ` Jens Axboe
2018-10-10 19:59     ` Bjorn Helgaas
2018-10-10 20:00       ` Jens Axboe
2018-10-04 21:27 ` [PATCH v9 08/13] IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-10-05  7:09   ` Christoph Hellwig
2018-10-04 21:27 ` [PATCH v9 09/13] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-10-05  7:09   ` Christoph Hellwig
2018-10-04 21:27 ` [PATCH v9 10/13] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-10-04 21:27 ` [PATCH v9 11/13] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-10-05  7:10   ` Christoph Hellwig
2018-10-05 15:39     ` Logan Gunthorpe
2018-10-04 21:27 ` [PATCH v9 12/13] nvmet: Introduce helper functions to allocate and free request SGLs Logan Gunthorpe
2018-10-05  7:11   ` Christoph Hellwig
2018-10-04 21:27 ` [PATCH v9 13/13] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
2018-10-04 22:20   ` Sagi Grimberg
2018-10-04 22:29     ` Logan Gunthorpe
2018-10-05  7:07       ` Christoph Hellwig
2018-10-05  7:34         ` Sagi Grimberg
2018-10-05 15:42         ` Logan Gunthorpe
2018-10-10 20:19 ` [PATCH v9 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory Bjorn Helgaas
2018-10-10 23:03   ` Logan Gunthorpe
2018-10-11  3:18     ` Bjorn Helgaas
2018-10-11 15:38       ` Logan Gunthorpe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181004212747.6301-5-logang@deltatee.com \
    --to=logang@deltatee.com \
    --cc=alex.williamson@redhat.com \
    --cc=axboe@kernel.dk \
    --cc=benh@kernel.crashing.org \
    --cc=bhelgaas@google.com \
    --cc=christian.koenig@amd.com \
    --cc=hch@lst.de \
    --cc=jgg@mellanox.com \
    --cc=jglisse@redhat.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=maxg@mellanox.com \
    --subject='Re: [PATCH v9 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).