[PATCH v3] PCI: Adjust visibility of boot_display attribute instead of creation

[PATCH v3] PCI: Adjust visibility of boot_display attribute instead of creation

[Mario Limonciello]

From: Mario Limonciello <mario.limonciello@amd.com>

There is a desire to avoid creating new sysfs files late, so instead
of dynamically deciding to create the boot_display attribute, make
it static and use sysfs_update_group() to adjust visibility on the
applicable devices.

This also fixes a compilation failure when compiled without
CONFIG_VIDEO on sparc.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20250718224118.5b3f22b0@canb.auug.org.au/
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v3:
 * Move to pci_sysfs_init()
v2:
 * Change to sysfs_update_group() instead
---
 drivers/pci/pci-sysfs.c | 67 ++++++++++++++++++-----------------------
 1 file changed, 29 insertions(+), 38 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 6b1a0ae254d3a..65ba67af0f6cc 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1059,37 +1059,6 @@ void pci_remove_legacy_files(struct pci_bus *b)
 }
 #endif /* HAVE_PCI_LEGACY */
 
-/**
- * pci_create_boot_display_file - create a file in sysfs for @dev
- * @pdev: dev in question
- *
- * Creates a file `boot_display` in sysfs for the PCI device @pdev
- * if it is the boot display device.
- */
-static int pci_create_boot_display_file(struct pci_dev *pdev)
-{
-#ifdef CONFIG_VIDEO
-	if (video_is_primary_device(&pdev->dev))
-		return sysfs_create_file(&pdev->dev.kobj, &dev_attr_boot_display.attr);
-#endif
-	return 0;
-}
-
-/**
- * pci_remove_boot_display_file - remove the boot display file for @dev
- * @pdev: dev in question
- *
- * Removes the file `boot_display` in sysfs for the PCI device @pdev
- * if it is the boot display device.
- */
-static void pci_remove_boot_display_file(struct pci_dev *pdev)
-{
-#ifdef CONFIG_VIDEO
-	if (video_is_primary_device(&pdev->dev))
-		sysfs_remove_file(&pdev->dev.kobj, &dev_attr_boot_display.attr);
-#endif
-}
-
 #if defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE)
 /**
  * pci_mmap_resource - map a PCI resource into user memory space
@@ -1691,17 +1660,34 @@ static const struct attribute_group pci_dev_resource_resize_group = {
 	.is_visible = resource_resize_is_visible,
 };
 
-int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
+static struct attribute *pci_display_attrs[] = {
+	&dev_attr_boot_display.attr,
+	NULL,
+};
+
+static umode_t pci_boot_display_visible(struct kobject *kobj,
+					struct attribute *a, int n)
 {
-	int retval;
+#ifdef CONFIG_VIDEO
+	struct device *dev = kobj_to_dev(kobj);
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	if (a == &dev_attr_boot_display.attr && video_is_primary_device(&pdev->dev))
+		return a->mode;
+#endif
+	return 0;
+}
 
+static const struct attribute_group pci_display_attr_group = {
+	.attrs = pci_display_attrs,
+	.is_visible = pci_boot_display_visible,
+};
+
+int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
+{
 	if (!sysfs_initialized)
 		return -EACCES;
 
-	retval = pci_create_boot_display_file(pdev);
-	if (retval)
-		return retval;
-
 	return pci_create_resource_files(pdev);
 }
 
@@ -1716,7 +1702,6 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
 	if (!sysfs_initialized)
 		return;
 
-	pci_remove_boot_display_file(pdev);
 	pci_remove_resource_files(pdev);
 }
 
@@ -1728,6 +1713,11 @@ static int __init pci_sysfs_init(void)
 
 	sysfs_initialized = 1;
 	for_each_pci_dev(pdev) {
+		retval = sysfs_update_group(&pdev->dev.kobj, &pci_display_attr_group);
+		if (retval) {
+			pci_dev_put(pdev);
+			return retval;
+		}
 		retval = pci_create_sysfs_dev_files(pdev);
 		if (retval) {
 			pci_dev_put(pdev);
@@ -1845,6 +1835,7 @@ static const struct attribute_group pcie_dev_attr_group = {
 
 const struct attribute_group *pci_dev_attr_groups[] = {
 	&pci_dev_attr_group,
+	&pci_display_attr_group,
 	&pci_dev_hp_attr_group,
 #ifdef CONFIG_PCI_IOV
 	&sriov_pf_dev_attr_group,
-- 
2.43.0