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powerpc/iommu: Don't detach device without IOMMU group

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Some devices, for example PCI root port, don't have IOMMU table and
group. We needn't detach them from their IOMMU group. Otherwise, it
potentially incurs kernel crash because of referring NULL IOMMU group
as following backtrace indicates:

  .iommu_group_remove_device+0x74/0x1b0
  .iommu_bus_notifier+0x94/0xb4
  .notifier_call_chain+0x78/0xe8
  .__blocking_notifier_call_chain+0x7c/0xbc
  .blocking_notifier_call_chain+0x38/0x48
  .device_del+0x50/0x234
  .pci_remove_bus_device+0x88/0x138
  .pci_stop_and_remove_bus_device+0x2c/0x40
  .pcibios_remove_pci_devices+0xcc/0xfc
  .pcibios_remove_pci_devices+0x3c/0xfc

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Gavin Shan 2014-01-13 11:36:22 +08:00 committed by Benjamin Herrenschmidt
parent f26c7a035b
commit 0c4b9e27b0
1 changed files with 11 additions and 0 deletions
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11
arch/powerpc/kernel/iommu.c
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@ -1144,6 +1144,17 @@ EXPORT_SYMBOL_GPL(iommu_add_device);
void iommu_del_device(struct device *dev)
{
/*
* Some devices might not have IOMMU table and group
* and we needn't detach them from the associated
* IOMMU groups
*/
if (!dev->iommu_group) {
pr_debug("iommu_tce: skipping device %s with no tbl\n",
dev_name(dev));
return;
}
iommu_group_remove_device(dev);
}
EXPORT_SYMBOL_GPL(iommu_del_device);