ACPI / hotplug: Introduce common hotplug function acpi_device_hotplug()

Modify the common ACPI device hotplug code to always queue up the
same function, acpi_device_hotplug(), using acpi_hotplug_execute()
and make the PCI host bridge hotplug code use that function too for
device hot removal.

This allows some code duplication to be reduced and a race condition
where the relevant ACPI handle may become invalid between the
notification handler and the function queued up by it via
acpi_hotplug_execute() to be avoided.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 809b8082c134029250ef9c7b9f2167a7c04b78a4..a0d42cf5b0c575d1d21d1c2166978cce56d42c94 100644 (file)
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -89,7 +89,7 @@ void acpi_device_add_finalize(struct acpi_device *device);
 void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
 int acpi_bind_one(struct device *dev, acpi_handle handle);
 int acpi_unbind_one(struct device *dev);
-void acpi_bus_device_eject(void *data, u32 ost_src);
+void acpi_device_hotplug(void *data, u32 ost_src);
 bool acpi_device_is_present(struct acpi_device *adev);
 
 /* --------------------------------------------------------------------------

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 4076491c6ded1840000e4521ef7e129e0d547092..ca05064f3ff72d56b8d5116f3bce60b256d29c84 100644 (file)
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -683,11 +683,13 @@ static void hotplug_event_root(void *data, u32 type)
                if (!root)
                        break;
 
+               acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
+                                         ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
                get_device(&root->device->dev);
 
                acpi_scan_lock_release();
 
-               acpi_bus_device_eject(root->device, ACPI_NOTIFY_EJECT_REQUEST);
+               acpi_device_hotplug(root->device, ACPI_NOTIFY_EJECT_REQUEST);
                return;
        default:
                acpi_handle_warn(handle,

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 4fa416f94f5291aac6fb49fdda57db1cd1673a61..dd0ff9de9277ce4aeceaf7e2abbf42dc779a5278 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -206,12 +206,8 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
        acpi_status status;
        unsigned long long sta;
 
-       /* If there is no handle, the device node has been unregistered. */
-       if (!handle) {
-               dev_dbg(&device->dev, "ACPI handle missing\n");
-               put_device(&device->dev);
-               return -EINVAL;
-       }
+       if (device->handler && device->handler->hotplug.mode == AHM_CONTAINER)
+               kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
 
        /*
         * Carry out two passes here and ignore errors in the first pass,
@@ -230,7 +226,6 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
                dev_warn(errdev, "Offline disabled.\n");
                acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
                                    acpi_bus_online, NULL, NULL, NULL);
-               put_device(&device->dev);
                return -EPERM;
        }
        acpi_bus_offline(handle, 0, (void *)false, (void **)&errdev);
@@ -249,7 +244,6 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
                        acpi_walk_namespace(ACPI_TYPE_ANY, handle,
                                            ACPI_UINT32_MAX, acpi_bus_online,
                                            NULL, NULL, NULL);
-                       put_device(&device->dev);
                        return -EBUSY;
                }
        }
@@ -259,9 +253,6 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
 
        acpi_bus_trim(device);
 
-       put_device(&device->dev);
-       device = NULL;
-
        acpi_evaluate_lck(handle, 0);
        /*
         * TBD: _EJD support.
@@ -288,77 +279,74 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
        return 0;
 }
 
-void acpi_bus_device_eject(void *data, u32 ost_src)
+static int acpi_scan_device_check(struct acpi_device *adev)
 {
-       struct acpi_device *device = data;
-       acpi_handle handle = device->handle;
-       u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
        int error;
 
-       lock_device_hotplug();
-       mutex_lock(&acpi_scan_lock);
-
-       if (ost_src == ACPI_NOTIFY_EJECT_REQUEST)
-               acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
-                                         ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
-
-       if (device->handler && device->handler->hotplug.mode == AHM_CONTAINER)
-               kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
-
-       error = acpi_scan_hot_remove(device);
-       if (error == -EPERM) {
-               goto err_support;
-       } else if (error) {
-               goto err_out;
+       /*
+        * This function is only called for device objects for which matching
+        * scan handlers exist.  The only situation in which the scan handler is
+        * not attached to this device object yet is when the device has just
+        * appeared (either it wasn't present at all before or it was removed
+        * and then added again).
+        */
+       if (adev->handler) {
+               dev_warn(&adev->dev, "Already enumerated\n");
+               return -EBUSY;
        }
-
- out:
-       mutex_unlock(&acpi_scan_lock);
-       unlock_device_hotplug();
-       return;
-
- err_support:
-       ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
- err_out:
-       acpi_evaluate_hotplug_ost(handle, ost_src, ost_code, NULL);
-       goto out;
+       error = acpi_bus_scan(adev->handle);
+       if (error) {
+               dev_warn(&adev->dev, "Namespace scan failure\n");
+               return error;
+       }
+       if (adev->handler) {
+               if (adev->handler->hotplug.mode == AHM_CONTAINER)
+                       kobject_uevent(&adev->dev.kobj, KOBJ_ONLINE);
+       } else {
+               dev_warn(&adev->dev, "Enumeration failure\n");
+               return -ENODEV;
+       }
+       return 0;
 }
 
-static void acpi_scan_bus_device_check(void *data, u32 ost_source)
+void acpi_device_hotplug(void *data, u32 src)
 {
-       acpi_handle handle = data;
-       struct acpi_device *device;
        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+       struct acpi_device *adev = data;
        int error;
 
        lock_device_hotplug();
        mutex_lock(&acpi_scan_lock);
 
-       if (ost_source != ACPI_NOTIFY_BUS_CHECK) {
-               device = NULL;
-               acpi_bus_get_device(handle, &device);
-               if (acpi_device_enumerated(device)) {
-                       dev_warn(&device->dev, "Attempt to re-insert\n");
-                       goto out;
-               }
-       }
-       error = acpi_bus_scan(handle);
-       if (error) {
-               acpi_handle_warn(handle, "Namespace scan failure\n");
-               goto out;
-       }
-       device = NULL;
-       acpi_bus_get_device(handle, &device);
-       if (!acpi_device_enumerated(device)) {
-               acpi_handle_warn(handle, "Device not enumerated\n");
+       /*
+        * The device object's ACPI handle cannot become invalid as long as we
+        * are holding acpi_scan_lock, but it may have become invalid before
+        * that lock was acquired.
+        */
+       if (adev->handle == INVALID_ACPI_HANDLE)
                goto out;
+
+       switch (src) {
+       case ACPI_NOTIFY_BUS_CHECK:
+               error = acpi_bus_scan(adev->handle);
+               break;
+       case ACPI_NOTIFY_DEVICE_CHECK:
+               error = acpi_scan_device_check(adev);
+               break;
+       case ACPI_NOTIFY_EJECT_REQUEST:
+       case ACPI_OST_EC_OSPM_EJECT:
+               error = acpi_scan_hot_remove(adev);
+               break;
+       default:
+               error = -EINVAL;
+               break;
        }
-       ost_code = ACPI_OST_SC_SUCCESS;
-       if (device->handler && device->handler->hotplug.mode == AHM_CONTAINER)
-               kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);
+       if (!error)
+               ost_code = ACPI_OST_SC_SUCCESS;
 
  out:
-       acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
+       acpi_evaluate_hotplug_ost(adev->handle, src, ost_code, NULL);
+       put_device(&adev->dev);
        mutex_unlock(&acpi_scan_lock);
        unlock_device_hotplug();
 }
@@ -370,6 +358,9 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
        struct acpi_device *adev;
        acpi_status status;
 
+       if (acpi_bus_get_device(handle, &adev))
+               goto err_out;
+
        switch (type) {
        case ACPI_NOTIFY_BUS_CHECK:
                acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
@@ -384,24 +375,20 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
                        ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
                        goto err_out;
                }
-               if (acpi_bus_get_device(handle, &adev))
-                       goto err_out;
-
-               get_device(&adev->dev);
-               status = acpi_hotplug_execute(acpi_bus_device_eject, adev, type);
-               if (ACPI_SUCCESS(status))
-                       return;
-
-               put_device(&adev->dev);
-               goto err_out;
+               acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
+                                         ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+               break;
        default:
                /* non-hotplug event; possibly handled by other handler */
                return;
        }
-       status = acpi_hotplug_execute(acpi_scan_bus_device_check, handle, type);
+       get_device(&adev->dev);
+       status = acpi_hotplug_execute(acpi_device_hotplug, adev, type);
        if (ACPI_SUCCESS(status))
                return;
 
+       put_device(&adev->dev);
+
  err_out:
        acpi_evaluate_hotplug_ost(handle, type, ost_code, NULL);
 }
@@ -454,7 +441,7 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
        acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
                                  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
        get_device(&acpi_device->dev);
-       status = acpi_hotplug_execute(acpi_bus_device_eject, acpi_device,
+       status = acpi_hotplug_execute(acpi_device_hotplug, acpi_device,
                                      ACPI_OST_EC_OSPM_EJECT);
        if (ACPI_SUCCESS(status))
                return count;