Commit cb452a40 authored May 28, 2011 by Mike Travis Committed by David Woodhouse Jun 01, 2011

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>

parent 8fcc5372

drivers/pci/intel-iommu.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}