From cb452a4040bb051d92e85d6e7eb60c11734c1781 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Sat, 28 May 2011 13:15:03 -0500 Subject: intel-iommu: Speed up processing of the identity_mapping function From: Mike Travis commit cb452a4040bb051d92e85d6e7eb60c11734c1781 upstream. When there are a large count of PCI devices, and the pass through option for iommu is set, much time is spent in the identity_mapping function hunting though the iommu domains to check if a specific device is "identity mapped". Speed up the function by checking the cached info to see if it's mapped to the static identity domain. Signed-off-by: Mike Travis Reviewed-by: Mike Habeck Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- drivers/pci/intel-iommu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -2109,10 +2109,10 @@ static int identity_mapping(struct pci_d if (likely(!iommu_identity_mapping)) return 0; + info = pdev->dev.archdata.iommu; + if (info && info != DUMMY_DEVICE_DOMAIN_INFO) + return (info->domain == si_domain); - list_for_each_entry(info, &si_domain->devices, link) - if (info->dev == pdev) - return 1; return 0; }