[PATCH] Calgary IOMMU: fix reference counting of Calgary PCI devices

The pci_get_device() API decrements the reference count on the 'from'
parameter when it continues searching. Therefore, take a ref count on
Calgary bus when we initialize them in either translated or
non-translated mode.

Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 6 insertions, 4 deletions

diff --git a/arch/x86_64/kernel/pci-calgary.c b/arch/x86_64/kernel/pci-calgary.c
index 6c5da1d813f3..7302834718c8 100644
--- a/arch/x86_64/kernel/pci-calgary.c
+++ b/arch/x86_64/kernel/pci-calgary.c
@@ -786,6 +786,7 @@ static inline unsigned int __init locate_register_space(struct pci_dev *dev)
 
 static int __init calgary_init_one_nontraslated(struct pci_dev *dev)
 {
+        pci_dev_get(dev);
         dev->sysdata = NULL;
         dev->bus->self = dev;
 
@@ -810,6 +811,7 @@ static int __init calgary_init_one(struct pci_dev *dev)
         if (ret)
                 goto iounmap;
 
+        pci_dev_get(dev);
         dev->bus->self = dev;
         calgary_enable_translation(dev);
 
@@ -836,10 +838,9 @@ static int __init calgary_init(void)
                         calgary_init_one_nontraslated(dev);
                         continue;
                 }
-                if (!bus_info[dev->bus->number].tce_space && !translate_empty_slots) {
-                        pci_dev_put(dev);
+                if (!bus_info[dev->bus->number].tce_space && !translate_empty_slots)
                         continue;
-                }
+
                 ret = calgary_init_one(dev);
                 if (ret)
                         goto error;
@@ -860,9 +861,10 @@ error:
                 }
                 if (!bus_info[dev->bus->number].tce_space && !translate_empty_slots)
                         continue;
+
                 calgary_disable_translation(dev);
                 calgary_free_bus(dev);
-                pci_dev_put(dev);
+                pci_dev_put(dev); /* Undo calgary_init_one()'s pci_dev_get() */
         }
 
         return ret;