PCI: Catch attempts to disable already-disabled devices

Warn when disabling a device that has already been disabled.

[bhelgaas: message wording]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 5cb5820fae40..29a09b705f04 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1401,6 +1401,9 @@ pci_disable_device(struct pci_dev *dev)
         if (dr)
                 dr->enabled = 0;
 
+        dev_WARN_ONCE(&dev->dev, atomic_read(&dev->enable_cnt) <= 0,
+                      "disabling already-disabled device");
+
         if (atomic_sub_return(1, &dev->enable_cnt) != 0)
                 return;