PCI/sysfs: Convert "vpd" to static attribute

The "vpd" sysfs attribute allows access to Vital Product Data (VPD).
Previously it was dynamically created either by pci_bus_add_device() or the
pci_sysfs_init() initcall, but since it doesn't need to be created or
removed dynamically, we can use a static attribute so the device model
takes care of addition and removal automatically.

Convert "vpd" to a static attribute and use the .is_bin_visible() callback
to check whether the device supports VPD.

Remove pcie_vpd_create_sysfs_dev_files(),
pcie_vpd_remove_sysfs_dev_files(), pci_create_capabilities_sysfs(), and
pci_create_capabilities_sysfs(), which are no longer needed.

[bhelgaas: This is substantially the same as the earlier patch from Heiner
Kallweit <hkallweit1@gmail.com>.  I included Krzysztof's change here so all
the "convert to static attribute" changes are together.]

[bhelgaas: rename to vpd_read()/vpd_write() and pci_dev_vpd_attr_group]
Suggested-by: NOliver O'Halloran <oohall@gmail.com>
Based-on: https://lore.kernel.org/r/7703024f-8882-9eec-a122-599871728a89@gmail.comBased-on-patch-by: NHeiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/20210416205856.3234481-5-kw@linux.comSigned-off-by: NKrzysztof Wilczyński <kw@linux.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci-sysfs.c

@@ -1378,12 +1378,6 @@ static const struct attribute_group pci_dev_reset_attr_group = {
 	.is_visible = pci_dev_reset_attr_is_visible,
 };
 
-
-static void pci_create_capabilities_sysfs(struct pci_dev *dev)
-{
-	pcie_vpd_create_sysfs_dev_files(dev);
-}
-
 int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
 {
 	int retval;
@@ -1395,18 +1389,11 @@ int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
 	if (retval)
 		return retval;
 
-	/* add sysfs entries for various capabilities */
-	pci_create_capabilities_sysfs(pdev);
 	pci_create_firmware_label_files(pdev);
 
 	return 0;
 }
 
-static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
-{
-	pcie_vpd_remove_sysfs_dev_files(dev);
-}
-
 /**
  * pci_remove_sysfs_dev_files - cleanup PCI specific sysfs files
  * @pdev: device whose entries we should free
@@ -1418,7 +1405,6 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
 	if (!sysfs_initialized)
 		return;
 
-	pci_remove_capabilities_sysfs(pdev);
 	pci_remove_resource_files(pdev);
 	pci_remove_firmware_label_files(pdev);
 }
@@ -1514,6 +1500,7 @@ const struct attribute_group *pci_dev_groups[] = {
 	&pci_dev_config_attr_group,
 	&pci_dev_rom_attr_group,
 	&pci_dev_reset_attr_group,
+	&pci_dev_vpd_attr_group,
 	NULL,
 };
 

drivers/pci/pci.h

@@ -143,8 +143,7 @@ static inline bool pcie_downstream_port(const struct pci_dev *dev)
 
 int pci_vpd_init(struct pci_dev *dev);
 void pci_vpd_release(struct pci_dev *dev);
-void pcie_vpd_create_sysfs_dev_files(struct pci_dev *dev);
-void pcie_vpd_remove_sysfs_dev_files(struct pci_dev *dev);
+extern const struct attribute_group pci_dev_vpd_attr_group;
 
 /* PCI Virtual Channel */
 int pci_save_vc_state(struct pci_dev *dev);

drivers/pci/vpd.c

@@ -21,7 +21,6 @@ struct pci_vpd_ops {
 
 struct pci_vpd {
 	const struct pci_vpd_ops *ops;
-	struct bin_attribute *attr;	/* Descriptor for sysfs VPD entry */
 	struct mutex	lock;
 	unsigned int	len;
 	u16		flag;
@@ -428,41 +427,28 @@ static ssize_t vpd_write(struct file *filp, struct kobject *kobj,
 
 	return pci_write_vpd(dev, off, count, buf);
 }
+static BIN_ATTR(vpd, 0600, vpd_read, vpd_write, 0);
 
-void pcie_vpd_create_sysfs_dev_files(struct pci_dev *dev)
-{
-	int retval;
-	struct bin_attribute *attr;
-
-	if (!dev->vpd)
-		return;
+static struct bin_attribute *vpd_attrs[] = {
+	&bin_attr_vpd,
+	NULL,
+};
 
-	attr = kzalloc(sizeof(*attr), GFP_ATOMIC);
-	if (!attr)
-		return;
+static umode_t vpd_attr_is_visible(struct kobject *kobj,
+				   struct bin_attribute *a, int n)
+{
+	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
 
-	sysfs_bin_attr_init(attr);
-	attr->size = 0;
-	attr->attr.name = "vpd";
-	attr->attr.mode = S_IRUSR | S_IWUSR;
-	attr->read = vpd_read;
-	attr->write = vpd_write;
-	retval = sysfs_create_bin_file(&dev->dev.kobj, attr);
-	if (retval) {
-		kfree(attr);
-		return;
-	}
+	if (!pdev->vpd)
+		return 0;
 
-	dev->vpd->attr = attr;
+	return a->attr.mode;
 }
 
-void pcie_vpd_remove_sysfs_dev_files(struct pci_dev *dev)
-{
-	if (dev->vpd && dev->vpd->attr) {
-		sysfs_remove_bin_file(&dev->dev.kobj, dev->vpd->attr);
-		kfree(dev->vpd->attr);
-	}
-}
+const struct attribute_group pci_dev_vpd_attr_group = {
+	.bin_attrs = vpd_attrs,
+	.is_bin_visible = vpd_attr_is_visible,
+};
 
 int pci_vpd_find_tag(const u8 *buf, unsigned int off, unsigned int len, u8 rdt)
 {