PCI/sysfs: Compile pci-sysfs.c only if CONFIG_SYSFS=y

It is possible to enable CONFIG_PCI but disable CONFIG_SYSFS and for
space-constrained devices such as routers, such a configuration may
actually make sense.

However pci-sysfs.c is compiled even if CONFIG_SYSFS is disabled,
unnecessarily increasing the kernel's size.

To rectify that:

* Move pci_mmap_fits() to mmap.c.  It is not only needed by
  pci-sysfs.c, but also proc.c.

* Move pci_dev_type to probe.c and make it private.  It references
  pci_dev_attr_groups in pci-sysfs.c.  Make that public instead for
  consistency with pci_dev_groups, pcibus_groups and pci_bus_groups,
  which are likewise public and referenced by struct definitions in
  pci-driver.c and probe.c.

* Define pci_dev_groups, pci_dev_attr_groups, pcibus_groups and
  pci_bus_groups to NULL if CONFIG_SYSFS is disabled.  Provide empty
  static inlines for pci_{create,remove}_legacy_files() and
  pci_{create,remove}_sysfs_dev_files().

Result:

vmlinux size is reduced by 122996 bytes in my arm 32-bit test build.

Link: https://lore.kernel.org/r/85ca95ae8e4d57ccf082c5c069b8b21eb141846e.1698668982.git.lukas@wunner.de
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

drivers/pci/Makefile

@@ -4,7 +4,7 @@
 
 obj-$(CONFIG_PCI)		+= access.o bus.o probe.o host-bridge.o \
 				   remove.o pci.o pci-driver.o search.o \
-				   pci-sysfs.o rom.o setup-res.o irq.o vpd.o \
+				   rom.o setup-res.o irq.o vpd.o \
 				   setup-bus.o vc.o mmap.o setup-irq.o
 
 obj-$(CONFIG_PCI)		+= msi/
@@ -12,7 +12,7 @@ obj-$(CONFIG_PCI)		+= pcie/
 
 ifdef CONFIG_PCI
 obj-$(CONFIG_PROC_FS)		+= proc.o
-obj-$(CONFIG_SYSFS)		+= slot.o
+obj-$(CONFIG_SYSFS)		+= pci-sysfs.o slot.o
 obj-$(CONFIG_ACPI)		+= pci-acpi.o
 endif
 

drivers/pci/mmap.c

@@ -11,6 +11,8 @@
 #include <linux/mm.h>
 #include <linux/pci.h>
 
+#include "pci.h"
+
 #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
 
 static const struct vm_operations_struct pci_phys_vm_ops = {
@@ -50,3 +52,30 @@ int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
 }
 
 #endif
+
+#if (defined(CONFIG_SYSFS) || defined(CONFIG_PROC_FS)) && \
+    (defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE))
+
+int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma,
+		  enum pci_mmap_api mmap_api)
+{
+	resource_size_t pci_start = 0, pci_end;
+	unsigned long nr, start, size;
+
+	if (pci_resource_len(pdev, resno) == 0)
+		return 0;
+	nr = vma_pages(vma);
+	start = vma->vm_pgoff;
+	size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1;
+	if (mmap_api == PCI_MMAP_PROCFS) {
+		pci_resource_to_user(pdev, resno, &pdev->resource[resno],
+				     &pci_start, &pci_end);
+		pci_start >>= PAGE_SHIFT;
+	}
+	if (start >= pci_start && start < pci_start + size &&
+	    start + nr <= pci_start + size)
+		return 1;
+	return 0;
+}
+
+#endif

drivers/pci/pci-sysfs.c

@@ -1022,29 +1022,6 @@ void pci_remove_legacy_files(struct pci_bus *b)
 #endif /* HAVE_PCI_LEGACY */
 
 #if defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE)
-
-int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma,
-		  enum pci_mmap_api mmap_api)
-{
-	unsigned long nr, start, size;
-	resource_size_t pci_start = 0, pci_end;
-
-	if (pci_resource_len(pdev, resno) == 0)
-		return 0;
-	nr = vma_pages(vma);
-	start = vma->vm_pgoff;
-	size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1;
-	if (mmap_api == PCI_MMAP_PROCFS) {
-		pci_resource_to_user(pdev, resno, &pdev->resource[resno],
-				     &pci_start, &pci_end);
-		pci_start >>= PAGE_SHIFT;
-	}
-	if (start >= pci_start && start < pci_start + size &&
-			start + nr <= pci_start + size)
-		return 1;
-	return 0;
-}
-
 /**
  * pci_mmap_resource - map a PCI resource into user memory space
  * @kobj: kobject for mapping
@@ -1660,7 +1637,7 @@ static const struct attribute_group pcie_dev_attr_group = {
 	.is_visible = pcie_dev_attrs_are_visible,
 };
 
-static const struct attribute_group *pci_dev_attr_groups[] = {
+const struct attribute_group *pci_dev_attr_groups[] = {
 	&pci_dev_attr_group,
 	&pci_dev_hp_attr_group,
 #ifdef CONFIG_PCI_IOV
@@ -1677,7 +1654,3 @@ static const struct attribute_group *pci_dev_attr_groups[] = {
 #endif
 	NULL,
 };
-
-const struct device_type pci_dev_type = {
-	.groups = pci_dev_attr_groups,
-};

drivers/pci/pci.h

@@ -31,8 +31,6 @@ bool pcie_cap_has_rtctl(const struct pci_dev *dev);
 
 /* Functions internal to the PCI core code */
 
-int pci_create_sysfs_dev_files(struct pci_dev *pdev);
-void pci_remove_sysfs_dev_files(struct pci_dev *pdev);
 void pci_cleanup_rom(struct pci_dev *dev);
 #ifdef CONFIG_DMI
 extern const struct attribute_group pci_dev_smbios_attr_group;
@@ -152,7 +150,7 @@ static inline int pci_proc_detach_bus(struct pci_bus *bus) { return 0; }
 /* Functions for PCI Hotplug drivers to use */
 int pci_hp_add_bridge(struct pci_dev *dev);
 
-#ifdef HAVE_PCI_LEGACY
+#if defined(CONFIG_SYSFS) && defined(HAVE_PCI_LEGACY)
 void pci_create_legacy_files(struct pci_bus *bus);
 void pci_remove_legacy_files(struct pci_bus *bus);
 #else
@@ -185,10 +183,22 @@ static inline int pci_no_d1d2(struct pci_dev *dev)
 	return (dev->no_d1d2 || parent_dstates);
 
 }
+
+#ifdef CONFIG_SYSFS
+int pci_create_sysfs_dev_files(struct pci_dev *pdev);
+void pci_remove_sysfs_dev_files(struct pci_dev *pdev);
 extern const struct attribute_group *pci_dev_groups[];
+extern const struct attribute_group *pci_dev_attr_groups[];
 extern const struct attribute_group *pcibus_groups[];
-extern const struct device_type pci_dev_type;
 extern const struct attribute_group *pci_bus_groups[];
+#else
+static inline int pci_create_sysfs_dev_files(struct pci_dev *pdev) { return 0; }
+static inline void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { }
+#define pci_dev_groups NULL
+#define pci_dev_attr_groups NULL
+#define pcibus_groups NULL
+#define pci_bus_groups NULL
+#endif
 
 extern unsigned long pci_hotplug_io_size;
 extern unsigned long pci_hotplug_mmio_size;

drivers/pci/probe.c

@@ -2357,6 +2357,10 @@ static void pci_release_dev(struct device *dev)
 	kfree(pci_dev);
 }
 
+static const struct device_type pci_dev_type = {
+	.groups = pci_dev_attr_groups,
+};
+
 struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
 {
 	struct pci_dev *dev;