PCI/ERR: Reduce compile time for CONFIG_PCIEAER=n

The sole non-static function in err.c, pcie_do_recovery(), is only
called from:

* aer.c (if CONFIG_PCIEAER=y)
* dpc.c (if CONFIG_PCIE_DPC=y, which depends on CONFIG_PCIEAER)
* edr.c (if CONFIG_PCIE_EDR=y, which depends on CONFIG_PCIE_DPC)

Thus, err.c need not be compiled if CONFIG_PCIEAER=n.

Also, pci_uevent_ers() and pcie_clear_device_status(), which are called
from err.c, can be #ifdef'ed away unless CONFIG_PCIEAER=y.

Since x86_64_defconfig doesn't enable CONFIG_PCIEAER, this change may
slightly reduce compile time for anyone doing a test build with that
config.

Link: https://lore.kernel.org/r/98f9041151268c1c035ab64cca320ad86803f64a.1627638184.git.lukas@wunner.deSigned-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci-driver.c

@@ -1542,7 +1542,7 @@ static int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
-#if defined(CONFIG_PCIEPORTBUS) || defined(CONFIG_EEH)
+#if defined(CONFIG_PCIEAER) || defined(CONFIG_EEH)
 /**
  * pci_uevent_ers - emit a uevent during recovery path of PCI device
  * @pdev: PCI device undergoing error recovery

drivers/pci/pci.c

@@ -2218,6 +2218,7 @@ int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
 }
 EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state);
 
+#ifdef CONFIG_PCIEAER
 void pcie_clear_device_status(struct pci_dev *dev)
 {
 	u16 sta;
@@ -2225,6 +2226,7 @@ void pcie_clear_device_status(struct pci_dev *dev)
 	pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &sta);
 	pcie_capability_write_word(dev, PCI_EXP_DEVSTA, sta);
 }
+#endif
 
 /**
  * pcie_clear_root_pme_status - Clear root port PME interrupt status.

drivers/pci/pcie/Makefile

@@ -2,12 +2,12 @@
 #
 # Makefile for PCI Express features and port driver
 
-pcieportdrv-y			:= portdrv_core.o portdrv_pci.o err.o rcec.o
+pcieportdrv-y			:= portdrv_core.o portdrv_pci.o rcec.o
 
 obj-$(CONFIG_PCIEPORTBUS)	+= pcieportdrv.o
 
 obj-$(CONFIG_PCIEASPM)		+= aspm.o
-obj-$(CONFIG_PCIEAER)		+= aer.o
+obj-$(CONFIG_PCIEAER)		+= aer.o err.o
 obj-$(CONFIG_PCIEAER_INJECT)	+= aer_inject.o
 obj-$(CONFIG_PCIE_PME)		+= pme.o
 obj-$(CONFIG_PCIE_DPC)		+= dpc.o