[PATCH] iommu: narrow the search range by iterating on current bus

[Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

According to the comments and code, get_pci_function_alias_group() and
get_pci_alias_group() do the search on the same pci bus. This means we can
just iterate on the bus the pci device attaches to.

This patch narrows the search range by just iterating on the current bus
and fix one typo in comment.

Signed-off-by: Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/iommu/iommu.c |   22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3000051..0338a81 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -643,17 +643,15 @@ static struct iommu_group *get_pci_function_alias_group(struct pci_dev *pdev,
 	if (!pdev->multifunction || pci_acs_enabled(pdev, REQ_ACS_FLAGS))
 		return NULL;
 
-	for_each_pci_dev(tmp) {
-		if (tmp == pdev || tmp->bus != pdev->bus ||
+	list_for_each_entry(tmp, &pdev->bus->devices, bus_list) {
+		if (tmp == pdev ||
 		    PCI_SLOT(tmp->devfn) != PCI_SLOT(pdev->devfn) ||
 		    pci_acs_enabled(tmp, REQ_ACS_FLAGS))
 			continue;
 
 		group = get_pci_alias_group(tmp, devfns);
-		if (group) {
-			pci_dev_put(tmp);
+		if (group)
 			return group;
-		}
 	}
 
 	return NULL;
@@ -681,23 +679,19 @@ static struct iommu_group *get_pci_alias_group(struct pci_dev *pdev,
 	if (group)
 		return group;
 
-	for_each_pci_dev(tmp) {
-		if (tmp == pdev || tmp->bus != pdev->bus)
+	list_for_each_entry(tmp, &pdev->bus->devices, bus_list) {
+		if (tmp == pdev)
 			continue;
 
 		/* We alias them or they alias us */
 		if (pci_devs_are_dma_aliases(pdev, tmp)) {
 			group = get_pci_alias_group(tmp, devfns);
-			if (group) {
-				pci_dev_put(tmp);
+			if (group)
 				return group;
-			}
 
 			group = get_pci_function_alias_group(tmp, devfns);
-			if (group) {
-				pci_dev_put(tmp);
+			if (group)
 				return group;
-			}
 		}
 	}
 
@@ -794,7 +788,7 @@ struct iommu_group *pci_device_group(struct device *dev)
 
 	/*
 	 * Look for existing groups on non-isolated functions on the same
-	 * slot and aliases of those funcions, if any.  No need to clear
+	 * slot and aliases of those functions, if any. No need to clear
 	 * the search bitmap, the tested devfns are still valid.
 	 */
 	group = get_pci_function_alias_group(pdev, (unsigned long *)devfns);
-- 
1.7.9.5