Merge branch 'pci/virtualization'

- Add rescan/remove locking when enabling/disabling SR-IOV, which solves
  list corruption on s390, where disabling SR-IOV also generates hotplug
  events (Niklas Schnelle)

- Add lockdep assertion in pci_stop_and_remove_bus_device() to catch
  device removal without appropriate locking (Niklas Schnelle)

* pci/virtualization:
  PCI: Add lockdep assertion in pci_stop_and_remove_bus_device()
  PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV

Author: bjorn-helgaas

drivers/pci/iov.c

@@ -629,15 +629,18 @@ static int sriov_add_vfs(struct pci_dev *dev, u16 num_vfs)
 	if (dev->no_vf_scan)
 		return 0;
 
+	pci_lock_rescan_remove();
 	for (i = 0; i < num_vfs; i++) {
 		rc = pci_iov_add_virtfn(dev, i);
 		if (rc)
 			goto failed;
 	}
+	pci_unlock_rescan_remove();
 	return 0;
 failed:
 	while (i--)
 		pci_iov_remove_virtfn(dev, i);
+	pci_unlock_rescan_remove();
 
 	return rc;
 }
@@ -762,8 +765,10 @@ static void sriov_del_vfs(struct pci_dev *dev)
 	struct pci_sriov *iov = dev->sriov;
 	int i;
 
+	pci_lock_rescan_remove();
 	for (i = 0; i < iov->num_VFs; i++)
 		pci_iov_remove_virtfn(dev, i);
+	pci_unlock_rescan_remove();
 }
 
 static void sriov_disable(struct pci_dev *dev)

drivers/pci/pci.h

@@ -89,6 +89,8 @@ struct pcie_tlp_log;
 extern const unsigned char pcie_link_speed[];
 extern bool pci_early_dump;
 
+extern struct mutex pci_rescan_remove_lock;
+
 bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
 bool pcie_cap_has_lnkctl2(const struct pci_dev *dev);
 bool pcie_cap_has_rtctl(const struct pci_dev *dev);

drivers/pci/probe.c

@@ -3507,7 +3507,7 @@ EXPORT_SYMBOL_GPL(pci_rescan_bus);
  * pci_rescan_bus(), pci_rescan_bus_bridge_resize() and PCI device removal
  * routines should always be executed under this mutex.
  */
-static DEFINE_MUTEX(pci_rescan_remove_lock);
+DEFINE_MUTEX(pci_rescan_remove_lock);
 
 void pci_lock_rescan_remove(void)
 {

drivers/pci/remove.c

@@ -140,6 +140,7 @@ static void pci_remove_bus_device(struct pci_dev *dev)
  */
 void pci_stop_and_remove_bus_device(struct pci_dev *dev)
 {
+	lockdep_assert_held(&pci_rescan_remove_lock);
 	pci_stop_bus_device(dev);
 	pci_remove_bus_device(dev);
 }