[PATCH v11 42/60] PCI: Skip required+optional if there is no optional

[Yinghai Lu]

If the bridge does not support hotplug and has no child with sriov support,
We will not have optional resources. We could get out early and
don't try required+optional allocation.

Also in the loop that update res with optional add info, skip resource
that add_size is 0.

Signed-off-by: Yinghai Lu <ying...@kernel.org>
---
 drivers/pci/setup-bus.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index a4f53ec..373f76f 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -449,6 +449,24 @@ static bool pci_need_to_release(unsigned long mask, struct 
resource *res)
        return false;   /* should not get here */
 }
 
+static bool has_addon(struct list_head *head,
+                       struct list_head *realloc_head)
+{
+       int add_count = 0;
+       struct pci_dev_resource *dev_res, *tmp_res;
+
+       /* check if we have add really */
+       list_for_each_entry(dev_res, head, list) {
+               tmp_res = res_to_dev_res(realloc_head, dev_res->res);
+               if (!tmp_res || !tmp_res->add_size)
+                       continue;
+
+               add_count++;
+       }
+
+       return add_count != 0;
+}
+
 static bool save_resources(struct list_head *head,
                           struct list_head *save_head)
 {
@@ -480,16 +498,24 @@ static bool 
__assign_resources_required_optional_sorted(struct list_head *head,
        struct pci_dev_resource *save_res;
        struct pci_dev_resource *dev_res, *tmp_res;
        unsigned long fail_type;
-       resource_size_t add_align;
+       resource_size_t add_align, add_size;
        struct resource *res;
 
+       if (!has_addon(head, realloc_head))
+               return false;
+
        if (!save_resources(head, &save_head))
                return false;
 
        /* Update res in head list with add_size in realloc_head list */
        list_for_each_entry(dev_res, head, list) {
                res = dev_res->res;
-               res->end += get_res_add_size(realloc_head, res);
+               add_size = get_res_add_size(realloc_head, res);
+
+               if (!add_size)
+                       continue;
+
+               res->end += add_size;
 
                /*
                 * There are two kinds of additional resources in the list:
@@ -577,7 +603,7 @@ static void __assign_resources_sorted(struct list_head 
*head,
         */
 
        /* Check required+optional add */
-       if (realloc_head && !list_empty(realloc_head) &&
+       if (realloc_head &&
            __assign_resources_required_optional_sorted(head, realloc_head))
                return;
 
-- 
1.8.4.5