This patch enhances PCI resource assignemnt logic to support PCI bus lock
mechanism.

Signed-off-by: Jiang Liu <liu...@gmail.com>
---
 drivers/pci/setup-bus.c |   65 +++++++++++++++++++++++++++++++++++------------
 1 file changed, 49 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 192172c..08bac37 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -47,6 +47,7 @@ static void free_list(struct list_head *head)
 
        list_for_each_entry_safe(dev_res, tmp, head, list) {
                list_del(&dev_res->list);
+               pci_dev_put(dev_res->dev);
                kfree(dev_res);
        }
 }
@@ -73,7 +74,7 @@ static int add_to_list(struct list_head *head,
        }
 
        tmp->res = res;
-       tmp->dev = dev;
+       tmp->dev = pci_dev_get(dev);
        tmp->start = res->start;
        tmp->end = res->end;
        tmp->flags = res->flags;
@@ -93,6 +94,7 @@ static void remove_from_list(struct list_head *head,
        list_for_each_entry_safe(dev_res, tmp, head, list) {
                if (dev_res->res == res) {
                        list_del(&dev_res->list);
+                       pci_dev_put(dev_res->dev);
                        kfree(dev_res);
                        break;
                }
@@ -151,7 +153,7 @@ static void pdev_sort_resources(struct pci_dev *dev, struct 
list_head *head)
                        panic("pdev_sort_resources(): "
                              "kmalloc() failed!\n");
                tmp->res = r;
-               tmp->dev = dev;
+               tmp->dev = pci_dev_get(dev);
 
                /* fallback is smallest one or list is empty*/
                n = head;
@@ -257,6 +259,7 @@ static void reassign_resources_sorted(struct list_head 
*realloc_head,
                }
 out:
                list_del(&add_res->list);
+               pci_dev_put(add_res->dev);
                kfree(add_res);
        }
 }
@@ -982,15 +985,16 @@ handle_done:
        ;
 }
 
-void __ref __pci_bus_size_bridges(struct pci_bus *bus,
+static void __ref __pci_bus_size_bridges(struct pci_bus *bus,
                        struct list_head *realloc_head)
 {
        struct pci_dev *dev;
+       struct pci_bus *b;
        unsigned long mask, prefmask;
        resource_size_t additional_mem_size = 0, additional_io_size = 0;
 
        list_for_each_entry(dev, &bus->devices, bus_list) {
-               struct pci_bus *b = dev->subordinate;
+               b = pci_lock_subordinate(dev, PCI_BUS_STATE_STOPPING - 1);
                if (!b)
                        continue;
 
@@ -1004,6 +1008,8 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
                        __pci_bus_size_bridges(b, realloc_head);
                        break;
                }
+
+               pci_bus_unlock(b);
        }
 
        /* The root bus? */
@@ -1063,7 +1069,7 @@ static void __ref __pci_bus_assign_resources(const struct 
pci_bus *bus,
        pbus_assign_resources_sorted(bus, realloc_head, fail_head);
 
        list_for_each_entry(dev, &bus->devices, bus_list) {
-               b = dev->subordinate;
+               b = pci_lock_subordinate(dev, PCI_BUS_STATE_STOPPING - 1);
                if (!b)
                        continue;
 
@@ -1084,6 +1090,8 @@ static void __ref __pci_bus_assign_resources(const struct 
pci_bus *bus,
                                 "%04x:%02x\n", pci_domain_nr(b), b->number);
                        break;
                }
+
+               pci_bus_unlock(b);
        }
 }
 
@@ -1098,11 +1106,11 @@ static void __ref __pci_bridge_assign_resources(const 
struct pci_dev *bridge,
                                         struct list_head *fail_head)
 {
        struct pci_bus *b;
+       struct pci_dev *dev = (struct pci_dev *)bridge;
 
-       pdev_assign_resources_sorted((struct pci_dev *)bridge,
-                                        add_head, fail_head);
+       pdev_assign_resources_sorted(dev, add_head, fail_head);
 
-       b = bridge->subordinate;
+       b = pci_lock_subordinate(dev, PCI_BUS_STATE_STOPPING - 1);
        if (!b)
                return;
 
@@ -1122,7 +1130,10 @@ static void __ref __pci_bridge_assign_resources(const 
struct pci_dev *bridge,
                         "%04x:%02x\n", pci_domain_nr(b), b->number);
                break;
        }
+
+       pci_bus_unlock(b);
 }
+
 static void pci_bridge_release_resources(struct pci_bus *bus,
                                          unsigned long type)
 {
@@ -1169,6 +1180,7 @@ enum release_type {
        leaf_only,
        whole_subtree,
 };
+
 /*
  * try to release pci bridge resources that is from leaf bridge,
  * so we can allocate big new one later
@@ -1190,9 +1202,14 @@ static void __ref 
pci_bus_release_bridge_resources(struct pci_bus *bus,
                if ((dev->class >> 8) != PCI_CLASS_BRIDGE_PCI)
                        continue;
 
-               if (rel_type == whole_subtree)
+               if (rel_type != whole_subtree)
+                       continue;
+
+               if (pci_bus_lock_states(b, PCI_BUS_STATE_STOPPING - 1) > 0) {
                        pci_bus_release_bridge_resources(b, type,
                                                 whole_subtree);
+                       pci_bus_unlock(b);
+               }
        }
 
        if (pci_is_root_bus(bus))
@@ -1253,6 +1270,7 @@ static int __init pci_bus_get_depth(struct pci_bus *bus)
 
        return depth;
 }
+
 static int __init pci_get_max_depth(void)
 {
        int depth = 0;
@@ -1285,6 +1303,7 @@ enum enable_type {
 };
 
 static enum enable_type pci_realloc_enable __initdata = undefined;
+
 void __init pci_realloc_get_opt(char *str)
 {
        if (!strncmp(str, "off", 3))
@@ -1292,6 +1311,7 @@ void __init pci_realloc_get_opt(char *str)
        else if (!strncmp(str, "on", 2))
                pci_realloc_enable = user_enabled;
 }
+
 static bool __init pci_realloc_enabled(void)
 {
        return pci_realloc_enable >= user_enabled;
@@ -1428,7 +1448,7 @@ enable_and_dump:
 
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 {
-       struct pci_bus *parent = bridge->subordinate;
+       struct pci_bus *parent;
        LIST_HEAD(add_list); /* list of resources that
                                        want additional resources */
        int tried_times = 0;
@@ -1438,6 +1458,10 @@ void pci_assign_unassigned_bridge_resources(struct 
pci_dev *bridge)
        unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
                                  IORESOURCE_PREFETCH;
 
+       parent = pci_lock_subordinate(bridge, PCI_BUS_STATE_STOPPING - 1);
+       if (!parent)
+               return;
+
 again:
        __pci_bus_size_bridges(parent, &add_list);
        __pci_bridge_assign_resources(bridge, &add_list, &fail_head);
@@ -1464,8 +1488,13 @@ again:
                struct pci_bus *bus = fail_res->dev->bus;
                unsigned long flags = fail_res->flags;
 
+               if (bus != parent && pci_bus_lock_states(bus,
+                                       PCI_BUS_STATE_STOPPING - 1) < 0)
+                       continue;
                pci_bus_release_bridge_resources(bus, flags & type_mask,
                                                 whole_subtree);
+               if (bus != parent)
+                       pci_bus_unlock(bus);
        }
        /* restore size and flags */
        list_for_each_entry(fail_res, &fail_head, list) {
@@ -1485,6 +1514,7 @@ enable_all:
        retval = pci_reenable_device(bridge);
        pci_set_master(bridge);
        pci_enable_bridges(parent);
+       pci_bus_unlock(parent);
 }
 EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources);
 
@@ -1502,19 +1532,22 @@ unsigned int __ref pci_rescan_bus(struct pci_bus *bus)
 {
        unsigned int max;
        struct pci_dev *dev;
+       struct pci_bus *b;
        LIST_HEAD(add_list); /* list of resources that
                                        want additional resources */
 
        max = pci_scan_child_bus(bus);
 
-       down_read(&pci_bus_sem);
        list_for_each_entry(dev, &bus->devices, bus_list)
                if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
-                   dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
-                       if (dev->subordinate)
-                               __pci_bus_size_bridges(dev->subordinate,
-                                                        &add_list);
-       up_read(&pci_bus_sem);
+                   dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
+                       b = pci_lock_subordinate(dev,
+                                       PCI_BUS_STATE_STOPPING - 1);
+                       if (b) {
+                               __pci_bus_size_bridges(b, &add_list);
+                               pci_bus_unlock(b);
+                       }
+               }
        __pci_bus_assign_resources(bus, &add_list, NULL);
        BUG_ON(!list_empty(&add_list));
 
-- 
1.7.9.5

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