ACPI / hotplug / PCI: Add hotplug contexts to PCI host bridges

After relatively recent changes in the ACPI-based PCI hotplug
(ACPIPHP) code, the acpiphp_check_host_bridge() executed for PCI
host bridges via acpi_pci_root_scan_dependent() doesn't do anything
useful, because those bridges do not have hotplug contexts.  That
happens by mistake, so fix it by making acpiphp_enumerate_slots()
add hotplug contexts to PCI host bridges too and modify
acpiphp_remove_slots() to drop those contexts for host bridges
as appropriate.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=76901
Fixes: 2d8b1d566a5f (ACPI / hotplug / PCI: Get rid of check_sub_bridges())
Reported-and-tested-by: Gavin Guo <gavin.guo@canonical.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/pci/hotplug/acpiphp.h b/drivers/pci/hotplug/acpiphp.h
index 2b85924..b0e61bf 100644 (file)
--- a/drivers/pci/hotplug/acpiphp.h
+++ b/drivers/pci/hotplug/acpiphp.h
@@ -142,6 +142,16 @@ static inline acpi_handle func_to_handle(struct acpiphp_func *func)
        return func_to_acpi_device(func)->handle;
 }
 
+struct acpiphp_root_context {
+       struct acpi_hotplug_context hp;
+       struct acpiphp_bridge *root_bridge;
+};
+
+static inline struct acpiphp_root_context *to_acpiphp_root_context(struct acpi_hotplug_context *hp)
+{
+       return container_of(hp, struct acpiphp_root_context, hp);
+}
+
 /*
  * struct acpiphp_attention_info - device specific attention registration
  *

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 75e1783..91aa3d7 100644 (file)
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -373,17 +373,13 @@ static acpi_status acpiphp_add_context(acpi_handle handle, u32 lvl, void *data,
 
 static struct acpiphp_bridge *acpiphp_dev_to_bridge(struct acpi_device *adev)
 {
-       struct acpiphp_context *context;
        struct acpiphp_bridge *bridge = NULL;
 
        acpi_lock_hp_context();
-       context = acpiphp_get_context(adev);
-       if (context) {
-               bridge = context->bridge;
+       if (adev->hp) {
+               bridge = to_acpiphp_root_context(adev->hp)->root_bridge;
                if (bridge)
                        get_bridge(bridge);
-
-               acpiphp_put_context(context);
        }
        acpi_unlock_hp_context();
        return bridge;
@@ -881,7 +877,17 @@ void acpiphp_enumerate_slots(struct pci_bus *bus)
         */
        get_device(&bus->dev);
 
-       if (!pci_is_root_bus(bridge->pci_bus)) {
+       acpi_lock_hp_context();
+       if (pci_is_root_bus(bridge->pci_bus)) {
+               struct acpiphp_root_context *root_context;
+
+               root_context = kzalloc(sizeof(*root_context), GFP_KERNEL);
+               if (!root_context)
+                       goto err;
+
+               root_context->root_bridge = bridge;
+               acpi_set_hp_context(adev, &root_context->hp, NULL, NULL, NULL);
+       } else {
                struct acpiphp_context *context;
 
                /*
@@ -890,21 +896,16 @@ void acpiphp_enumerate_slots(struct pci_bus *bus)
                 * parent is going to be handled by pciehp, in which case this
                 * bridge is not interesting to us either.
                 */
-               acpi_lock_hp_context();
                context = acpiphp_get_context(adev);
-               if (!context) {
-                       acpi_unlock_hp_context();
-                       put_device(&bus->dev);
-                       pci_dev_put(bridge->pci_dev);
-                       kfree(bridge);
-                       return;
-               }
+               if (!context)
+                       goto err;
+
                bridge->context = context;
                context->bridge = bridge;
                /* Get a reference to the parent bridge. */
                get_bridge(context->func.parent);
-               acpi_unlock_hp_context();
        }
+       acpi_unlock_hp_context();
 
        /* Must be added to the list prior to calling acpiphp_add_context(). */
        mutex_lock(&bridge_mutex);
@@ -919,6 +920,30 @@ void acpiphp_enumerate_slots(struct pci_bus *bus)
                cleanup_bridge(bridge);
                put_bridge(bridge);
        }
+       return;
+
+ err:
+       acpi_unlock_hp_context();
+       put_device(&bus->dev);
+       pci_dev_put(bridge->pci_dev);
+       kfree(bridge);
+}
+
+void acpiphp_drop_bridge(struct acpiphp_bridge *bridge)
+{
+       if (pci_is_root_bus(bridge->pci_bus)) {
+               struct acpiphp_root_context *root_context;
+               struct acpi_device *adev;
+
+               acpi_lock_hp_context();
+               adev = ACPI_COMPANION(bridge->pci_bus->bridge);
+               root_context = to_acpiphp_root_context(adev->hp);
+               adev->hp = NULL;
+               acpi_unlock_hp_context();
+               kfree(root_context);
+       }
+       cleanup_bridge(bridge);
+       put_bridge(bridge);
 }
 
 /**
@@ -936,8 +961,7 @@ void acpiphp_remove_slots(struct pci_bus *bus)
        list_for_each_entry(bridge, &bridge_list, list)
                if (bridge->pci_bus == bus) {
                        mutex_unlock(&bridge_mutex);
-                       cleanup_bridge(bridge);
-                       put_bridge(bridge);
+                       acpiphp_drop_bridge(bridge);
                        return;
                }