PCI: Add lockdep assertion in pci_stop_and_remove_bus_device()

Removing a PCI devices requires holding pci_rescan_remove_lock. Prompted by
this being missed in sriov_disable() and going unnoticed since its
inception, add a lockdep assert so this doesn't get missed again in the
future.

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Julian Ruess <julianr@linux.ibm.com>
Link: https://patch.msgid.link/20250826-pci_fix_sriov_disable-v1-2-2d0bc938f2a3@linux.ibm.com

Author: niklas88

drivers/pci/pci.h

@@ -84,6 +84,8 @@ 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

@@ -3469,7 +3469,7 @@ 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

@@ -138,6 +138,7 @@ 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);
 }