powerpc/iommu: Remove IOMMU device references via bus notifier

commit 4ad04e5987115ece5fa8a0cf1dc72fcd4707e33e upstream.

After d905c5df9aef ("PPC: POWERNV: move iommu_add_device earlier"), the
refcnt on the kobject backing the IOMMU group for a PCI device is
elevated by each call to pci_dma_dev_setup_pSeriesLP() (via
set_iommu_table_base_and_group). When we go to dlpar a multi-function
PCI device out:

        iommu_reconfig_notifier ->
                iommu_free_table ->
                        iommu_group_put
                        BUG_ON(tbl->it_group)

We trip this BUG_ON, because there are still references on the table, so
it is not freed. Fix this by moving the powernv bus notifier to common
code and calling it for both powernv and pseries.

Fixes: d905c5df9aef ("PPC: POWERNV: move iommu_add_device earlier")
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Tested-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 42632c7a2a4e77e86fa0768646f30b7508365fd9..5b51ca28425e526934455247e92b3560235f1f9a 100644 (file)
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -113,6 +113,7 @@ extern void iommu_register_group(struct iommu_table *tbl,
                                 int pci_domain_number, unsigned long pe_num);
 extern int iommu_add_device(struct device *dev);
 extern void iommu_del_device(struct device *dev);
+extern int __init tce_iommu_bus_notifier_init(void);
 #else
 static inline void iommu_register_group(struct iommu_table *tbl,
                                        int pci_domain_number,
@@ -128,6 +129,11 @@ static inline int iommu_add_device(struct device *dev)
 static inline void iommu_del_device(struct device *dev)
 {
 }
+
+static inline int __init tce_iommu_bus_notifier_init(void)
+{
+        return 0;
+}
 #endif /* !CONFIG_IOMMU_API */
 
 static inline void set_iommu_table_base_and_group(struct device *dev,

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 48fb2c18fa8107ec7a40a4124ddd4d5c2ba8c733..2ee19a583b2bcdfbdafad83bc14653bda5a0ad6d 100644 (file)
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1175,4 +1175,30 @@ void iommu_del_device(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_del_device);
 
+static int tce_iommu_bus_notifier(struct notifier_block *nb,
+                unsigned long action, void *data)
+{
+        struct device *dev = data;
+
+        switch (action) {
+        case BUS_NOTIFY_ADD_DEVICE:
+                return iommu_add_device(dev);
+        case BUS_NOTIFY_DEL_DEVICE:
+                if (dev->iommu_group)
+                        iommu_del_device(dev);
+                return 0;
+        default:
+                return 0;
+        }
+}
+
+static struct notifier_block tce_iommu_bus_nb = {
+        .notifier_call = tce_iommu_bus_notifier,
+};
+
+int __init tce_iommu_bus_notifier_init(void)
+{
+        bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
+        return 0;
+}
 #endif /* CONFIG_IOMMU_API */

diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 8326838ab6f65123a6f3487d270ee43a285358f2..1e539d0199731a660f7f3cb60882b38fb8e349ea 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -815,31 +815,4 @@ void __init pnv_pci_init(void)
 #endif
 }
 
-static int tce_iommu_bus_notifier(struct notifier_block *nb,
-               unsigned long action, void *data)
-{
-       struct device *dev = data;
-
-       switch (action) {
-       case BUS_NOTIFY_ADD_DEVICE:
-               return iommu_add_device(dev);
-       case BUS_NOTIFY_DEL_DEVICE:
-               if (dev->iommu_group)
-                       iommu_del_device(dev);
-               return 0;
-       default:
-               return 0;
-       }
-}
-
-static struct notifier_block tce_iommu_bus_nb = {
-       .notifier_call = tce_iommu_bus_notifier,
-};
-
-static int __init tce_iommu_bus_notifier_init(void)
-{
-       bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
-       return 0;
-}
-
 subsys_initcall_sync(tce_iommu_bus_notifier_init);

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index de1ec54a2a57924ac2f3c29a6d43153e773e8aee..78723292c883ea0acfe42637a5e0ac7db60163f0 100644 (file)
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -1341,3 +1341,5 @@ static int __init disable_multitce(char *str)
 }
 
 __setup("multitce=", disable_multitce);
+
+machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init);