[PATCH 07/20] PCI/sysfs: Convert __resource_resize_store() to use static attributes

["Krzysztof Wilczyński" <kwilczynski@kernel.org>]

Currently, __resource_resize_store() calls pci_remove_resource_files()
and pci_create_resource_files() to tear down and recreate resource
files after a BAR resize.

Replace this with sysfs_update_groups(), which re-evaluates visibility
and also runs the .bin_size callback for the static resource attribute
groups after a BAR resize.

At the moment, the resize code references the static resource group
symbols, so wrap it and the resize group registration in pci_dev_groups[]
under the same "HAVE_PCI_MMAP || ARCH_GENERIC_PCI_MMAP_RESOURCE" guard.

While at it, add a warning if pci_resize_resource() fails to
expose potential failures, and rename resource_resize_is_visible()
to resource_resize_attr_is_visible() and the corresponding group
variable to align with the naming convention used by the resource
attribute groups.

Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
---
 drivers/pci/pci-sysfs.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index e56fddbe7914..1fabd0baeb56 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1386,6 +1386,12 @@ static const struct attribute_group pci_dev_resource_wc_attr_group = {
 	.bin_size = pci_dev_resource_bin_size,
 };
 
+static const struct attribute_group *pci_dev_resource_attr_groups[] = {
+	&pci_dev_resource_io_attr_group,
+	&pci_dev_resource_uc_attr_group,
+	&pci_dev_resource_wc_attr_group,
+	NULL,
+};
 #endif
 
 int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; }
@@ -1643,6 +1649,7 @@ static const struct attribute_group pci_dev_reset_method_attr_group = {
 	.is_visible = pci_dev_reset_attr_is_visible,
 };
 
+#if defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE)
 static ssize_t __resource_resize_show(struct device *dev, int n, char *buf)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
@@ -1692,14 +1699,15 @@ static ssize_t __resource_resize_store(struct device *dev, int n,
 	pci_write_config_word(pdev, PCI_COMMAND,
 			      cmd & ~PCI_COMMAND_MEMORY);
 
-	pci_remove_resource_files(pdev);
-
 	ret = pci_resize_resource(pdev, n, size, 0);
+	if (ret)
+		pci_warn(pdev, "Failed to resize BAR %d: %pe\n",
+			 n, ERR_PTR(ret));
 
 	pci_assign_unassigned_bus_resources(bus);
 
-	if (pci_create_resource_files(pdev))
-		pci_warn(pdev, "Failed to recreate resource files after BAR resizing\n");
+	if (sysfs_update_groups(&pdev->dev.kobj, pci_dev_resource_attr_groups))
+		pci_warn(pdev, "Failed to update resource groups after BAR resizing\n");
 
 	pci_write_config_word(pdev, PCI_COMMAND, cmd);
 pm_put:
@@ -1742,7 +1750,7 @@ static struct attribute *resource_resize_attrs[] = {
 	NULL,
 };
 
-static umode_t resource_resize_is_visible(struct kobject *kobj,
+static umode_t resource_resize_attr_is_visible(struct kobject *kobj,
 					  struct attribute *a, int n)
 {
 	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
@@ -1750,10 +1758,11 @@ static umode_t resource_resize_is_visible(struct kobject *kobj,
 	return pci_rebar_get_current_size(pdev, n) < 0 ? 0 : a->mode;
 }
 
-static const struct attribute_group pci_dev_resource_resize_group = {
+static const struct attribute_group pci_dev_resource_resize_attr_group = {
 	.attrs = resource_resize_attrs,
-	.is_visible = resource_resize_is_visible,
+	.is_visible = resource_resize_attr_is_visible,
 };
+#endif
 
 int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
 {
@@ -1872,6 +1881,7 @@ const struct attribute_group *pci_dev_groups[] = {
 	&pci_dev_resource_io_attr_group,
 	&pci_dev_resource_uc_attr_group,
 	&pci_dev_resource_wc_attr_group,
+	&pci_dev_resource_resize_attr_group,
 #endif
 	&pci_dev_config_attr_group,
 	&pci_dev_rom_attr_group,
@@ -1884,7 +1894,6 @@ const struct attribute_group *pci_dev_groups[] = {
 #ifdef CONFIG_ACPI
 	&pci_dev_acpi_attr_group,
 #endif
-	&pci_dev_resource_resize_group,
 	ARCH_PCI_DEV_GROUPS
 	NULL,
 };
-- 
2.53.0