[PATCH 02/12] pci-p2p: Add sysfs group to display p2pmem stats

[Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>]

Attributes display the total amount of P2P memory, the ammount available
and whether it is published or not.

Signed-off-by: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
---
 Documentation/ABI/testing/sysfs-bus-pci | 25 ++++++++++++++++
 drivers/pci/p2p.c                       | 51 +++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 44d4b2be92fd..7b80ea77faca 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -323,3 +323,28 @@ Description:
 
 		This is similar to /sys/bus/pci/drivers_autoprobe, but
 		affects only the VFs associated with a specific PF.
+
+What:		/sys/bus/pci/devices/.../p2pmem/available
+Date:		November 2017
+Contact:	Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
+Description:
+		If the device has any Peer-to-Peer memory registered, this
+	        file contains the ammount of memory that has not been
+		allocated (in decimal).
+
+What:		/sys/bus/pci/devices/.../p2pmem/size
+Date:		November 2017
+Contact:	Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
+Description:
+		If the device has any Peer-to-Peer memory registered, this
+	        file contains the total ammount of memory that the device
+		provides (in decimal).
+
+What:		/sys/bus/pci/devices/.../p2pmem/published
+Date:		November 2017
+Contact:	Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
+Description:
+		If the device has any Peer-to-Peer memory registered, this
+	        file contains a '1' if the memory has been published for
+		use inside the kernel or a '0' if it is only intended
+		for use within the driver that published it.
diff --git a/drivers/pci/p2p.c b/drivers/pci/p2p.c
index aa465ac9273d..03330c7b5e6d 100644
--- a/drivers/pci/p2p.c
+++ b/drivers/pci/p2p.c
@@ -28,6 +28,53 @@ struct pci_p2p {
 	bool published;
 };
 
+static ssize_t size_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	size_t size = 0;
+
+	if (pdev->p2p->pool)
+		size = gen_pool_size(pdev->p2p->pool);
+
+	return snprintf(buf, PAGE_SIZE, "%zd\n", size);
+}
+static DEVICE_ATTR_RO(size);
+
+static ssize_t available_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	size_t avail = 0;
+
+	if (pdev->p2p->pool)
+		avail = gen_pool_avail(pdev->p2p->pool);
+
+	return snprintf(buf, PAGE_SIZE, "%zd\n", avail);
+}
+static DEVICE_ATTR_RO(available);
+
+static ssize_t published_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", pdev->p2p->published);
+}
+static DEVICE_ATTR_RO(published);
+
+static struct attribute *p2pmem_attrs[] = {
+	&dev_attr_size.attr,
+	&dev_attr_available.attr,
+	&dev_attr_published.attr,
+	NULL,
+};
+
+static const struct attribute_group p2pmem_group = {
+	.attrs = p2pmem_attrs,
+	.name = "p2pmem",
+};
+
 static void pci_p2pmem_percpu_release(struct percpu_ref *ref)
 {
 	struct pci_p2p *p2p =
@@ -54,6 +101,7 @@ static void pci_p2pmem_release(void *data)
 	percpu_ref_exit(&pdev->p2p->devmap_ref);
 
 	gen_pool_destroy(pdev->p2p->pool);
+	sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);
 	pdev->p2p = NULL;
 }
 
@@ -82,6 +130,9 @@ static int pci_p2pmem_setup(struct pci_dev *pdev)
 	if (error)
 		goto out_pool_destroy;
 
+	if (sysfs_create_group(&pdev->dev.kobj, &p2pmem_group))
+		dev_warn(&pdev->dev, "failed to create p2p sysfs group\n");
+
 	pdev->p2p = p2p;
 
 	return 0;
-- 
2.11.0