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intel-iommu: Speed up processing of the identity_mapping function 

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 <travis@sgi.com>
Reviewed-by: Mike Habeck <habeck@sgi.com>
Cc: stable@kernel.org
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Mike Travis 2011-05-28 13:15:03 -05:00 committed by David Woodhouse
parent 8fcc5372fb
commit cb452a4040
1 changed files with 3 additions and 3 deletions
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6
drivers/pci/intel-iommu.c
View File

@ -2235,10 +2235,10 @@ static int identity_mapping(struct pci_dev *pdev)
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;
}