[PATCH v4 08/24] 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 these with sysfs_remove_groups() before the resize and
sysfs_create_groups() after, which re-evaluates visibility and
runs the .bin_size callback for the static resource attribute
groups.  Also, add a warning if pci_resize_resource() fails to
expose potential failures.

For architectures without HAVE_PCI_MMAP or ARCH_GENERIC_PCI_MMAP_RESOURCE,
define pci_dev_resource_attr_groups as NULL so the resize path compiles
unconditionally and sysfs_remove_groups() and sysfs_create_groups() become
no-ops.

While at it, rename the 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, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 2922905ff070..c0925bdc9ecd 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1386,6 +1386,14 @@ 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,
+};
+#else
+#define pci_dev_resource_attr_groups NULL
 #endif
 
 int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; }
@@ -1692,14 +1700,17 @@ 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);
+	sysfs_remove_groups(&pdev->dev.kobj, pci_dev_resource_attr_groups);
 
 	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_create_groups(&pdev->dev.kobj, pci_dev_resource_attr_groups))
+		pci_warn(pdev, "Failed to recreate resource groups after BAR resizing\n");
 
 	pci_write_config_word(pdev, PCI_COMMAND, cmd);
 pm_put:
@@ -1742,7 +1753,7 @@ 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));
@@ -1750,9 +1761,9 @@ 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,
 };
 
 int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
@@ -1873,6 +1884,7 @@ const struct attribute_group *pci_dev_groups[] = {
 	&pci_dev_resource_uc_attr_group,
 	&pci_dev_resource_wc_attr_group,
 #endif
+	&pci_dev_resource_resize_attr_group,
 	&pci_dev_config_attr_group,
 	&pci_dev_rom_attr_group,
 	&pci_dev_reset_attr_group,
@@ -1884,7 +1896,6 @@ 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