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 v8 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers
Date: Thu, 27 Sep 2018 10:54:11 -0600 [thread overview]
Message-ID: <20180927165420.5290-5-logang@deltatee.com> (raw)
In-Reply-To: <20180927165420.5290-1-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 ec56febf08fc..1438f79e95a2 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>
@@ -868,3 +870,83 @@ 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 f039c48990a5..5248540eead2 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -37,6 +37,10 @@ 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)
@@ -104,5 +108,16 @@ 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
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next prev parent reply other threads:[~2018-09-27 16:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-27 16:54 [PATCH v8 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 01/13] PCI/P2PDMA: Support peer-to-peer memory Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 02/13] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 03/13] PCI/P2PDMA: Add PCI p2pmem DMA mappings to adjust the bus offset Logan Gunthorpe
2018-09-27 16:54 ` Logan Gunthorpe [this message]
2018-09-27 16:54 ` [PATCH v8 05/13] docs-rst: Add a new directory for PCI documentation Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 06/13] PCI/P2PDMA: Add P2P DMA driver writer's documentation Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 07/13] block: Add PCI P2P flag for request queue and check support for requests Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 08/13] IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 09/13] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-09-27 17:10 ` Keith Busch
2018-09-27 16:54 ` [PATCH v8 10/13] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-09-27 17:10 ` Keith Busch
2018-09-27 16:54 ` [PATCH v8 11/13] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-09-27 17:09 ` Keith Busch
2018-09-27 16:54 ` [PATCH v8 12/13] nvmet: Introduce helper functions to allocate and free request SGLs Logan Gunthorpe
2018-09-27 16:54 ` [PATCH v8 13/13] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
2018-09-27 17:12 ` Keith Busch
2018-09-27 17:29 ` Logan Gunthorpe
2018-10-01 21:34 ` Sagi Grimberg
2018-10-01 21:55 ` Logan Gunthorpe
2018-10-01 22:23 ` Sagi Grimberg
2018-10-01 23:43 ` Logan Gunthorpe
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