[PATCH 15/36] PCI: Bail out early if there is no addon

Yinghai Lu
2015-07-06T23:41:42Z

If the bridge does not support hotplug or no child with sriov support
we could get out early before try must+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 <yinghai@kernel.org>
---
drivers/pci/setup-bus.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 48f5616..e2aedac 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -466,8 +466,21 @@ static bool __assign_resources_must_add_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;
+ int add_count = 0;
+
+ /* check if we have add really */
+ list_for_each_entry(dev_res, head, list) {
+ res = dev_res->res;
+ tmp_res = res_to_dev_res(realloc_head, res);
+ if (!tmp_res || !tmp_res->add_size)
+ continue;
+
+ add_count++;
+ }
+ if (!add_count)
+ return false;

/* Save original start, end, flags etc at first */
list_for_each_entry(dev_res, head, list)
@@ -479,7 +492,12 @@ static bool __assign_resources_must_add_sorted(struct list_head *head,
/* 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:
@@ -573,7 +591,7 @@ static void __assign_resources_sorted(struct list_head *head,
LIST_HEAD(local_fail_head);

/* Check must+optional add */
- if (realloc_head && !list_empty(realloc_head) &&
+ if (realloc_head &&
__assign_resources_must_add_sorted(head, realloc_head))
return;

--
1.8.4.5