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powerpc/iommu: Remove IOMMU device references via bus notifier

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After d905c5df9a ("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: d905c5df9a ("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>
This commit is contained in:
Nishanth Aravamudan
2015-02-21 11:00:50 -08:00
committed by Michael Ellerman
parent 875ebe940d
commit 4ad04e5987
4 changed files with 34 additions and 26 deletions
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26
arch/powerpc/kernel/iommu.c
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@@ -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 */