[PATCH 2/2] PCI: Add lockdep assertion in pci_stop_and_remove_bus_device()

[Niklas Schnelle]

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.

Reviewed-by: Benjamin Block <bblock@xxxxxxxxxxxxx>
Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
---
 drivers/pci/pci.h    | 2 ++
 drivers/pci/probe.c  | 2 +-
 drivers/pci/remove.c | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 34f65d69662e9f61f0c489ec58de2ce17d21c0c6..1ad2e3ab147f3b2c42b3257e4f366fc5e424ede3 100644
--- a/drivers/pci/pci.h
+++ b/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);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f41128f91ca76ab014ad669ae84a53032c7c6b6b..2b35bb39ab0366bbf86b43e721811575b9fbcefb 100644
--- a/drivers/pci/probe.c
+++ b/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)
 {
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 445afdfa6498edc88f1ef89df279af1419025495..0b9a609392cecba36a818bc496a0af64061c259a 100644
--- a/drivers/pci/remove.c
+++ b/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);
 }

-- 
2.48.1