PCI ASPM: remove get_root_port_link

By having a pointer to the root port link, we can remove loops in
get_root_port_link() to search the root port link.

Acked-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 11 insertions, 13 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 04b6a3098505..3d27c97e0486 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -33,6 +33,7 @@ struct aspm_latency {
 
 struct pcie_link_state {
         struct pci_dev *pdev;           /* Upstream component of the Link */
+        struct pcie_link_state *root;   /* pointer to the root port link */
         struct pcie_link_state *parent; /* pointer to the parent Link state */
         struct list_head sibling;       /* node in link_list */
         struct list_head children;      /* list of child link states */
@@ -486,26 +487,17 @@ static void __pcie_aspm_config_link(struct pcie_link_state *link, u32 state)
         link->aspm_enabled = state;
 }
 
-static struct pcie_link_state *get_root_port_link(struct pcie_link_state *link)
-{
-        struct pcie_link_state *root_port_link = link;
-        while (root_port_link->parent)
-                root_port_link = root_port_link->parent;
-        return root_port_link;
-}
-
 /* Check the whole hierarchy, and configure each link in the hierarchy */
 static void __pcie_aspm_configure_link_state(struct pcie_link_state *link,
                                              u32 state)
 {
-        struct pcie_link_state *leaf, *root = get_root_port_link(link);
+        struct pcie_link_state *leaf, *root = link->root;
 
         state &= (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
 
         /* Check all links who have specific root port link */
         list_for_each_entry(leaf, &link_list, sibling) {
-                if (!list_empty(&leaf->children) ||
-                    get_root_port_link(leaf) != root)
+                if (!list_empty(&leaf->children) || (leaf->root != root))
                         continue;
                 state = pcie_aspm_check_state(leaf, state);
         }
@@ -519,12 +511,12 @@ static void __pcie_aspm_configure_link_state(struct pcie_link_state *link,
          **/
         if (state & PCIE_LINK_STATE_L1) {
                 list_for_each_entry(leaf, &link_list, sibling) {
-                        if (get_root_port_link(leaf) == root)
+                        if (leaf->root == root)
                                 __pcie_aspm_config_link(leaf, state);
                 }
         } else {
                 list_for_each_entry_reverse(leaf, &link_list, sibling) {
-                        if (get_root_port_link(leaf) == root)
+                        if (leaf->root == root)
                                 __pcie_aspm_config_link(leaf, state);
                 }
         }
@@ -600,6 +592,12 @@ static struct pcie_link_state *pcie_aspm_setup_link_state(struct pci_dev *pdev)
                 link->parent = parent;
                 list_add(&link->link, &parent->children);
         }
+        /* Setup a pointer to the root port link */
+        if (!link->parent)
+                link->root = link;
+        else
+                link->root = link->parent->root;
+
         list_add(&link->sibling, &link_list);
 
         pdev->link_state = link;