[PATCH v2] Enhance dmar to support device hotplug

[Yijing Wang <wangyijing@huawei.com>]

This is the v2 patch, the v1 link: http://marc.info/?l=linux-pci&m=138364004628824&w=2

v1->v2: keep (pci_dev *) pointer array in dmar_drhd_uni, only use pci device id
		to update pci_dev * pointer info during device hotplug in intel iommu 
		driver notifier.

Currently, DMAR driver save target pci devices pointers for drhd/rmrr/atsr
in (pci_dev *) array, but never update these info after initialization.
It's not safe, because pci devices maybe hot added or removed during 
system running. They will have new pci_dev * pointer. So if there have 
two IOMMUs or more in system, these devices will find a wrong drhd during 
DMA mapping. And DMAR faults will occur. This patch save pci device id 
as well as (pci_dev *) to fix this issue. Pci device id will be used to update
pci_dev * poninter during device hotplug in intel iommu driver notifier.
Other, here use list to manage target devices for IOMMU, 
we can easily use list helper.

Yijing Wang (1):
  IOMMU: enhance dmar to support device hotplug

 drivers/iommu/dmar.c        |   82 +++++++++++-----------
 drivers/iommu/intel-iommu.c |  161 +++++++++++++++++++++++++++++-------------
 include/linux/dmar.h        |   24 ++++--
 3 files changed, 167 insertions(+), 100 deletions(-)