Merge branch 'acpi-hotplug'

* acpi-hotplug:
  ACPI / hotplug: Remove containers synchronously
  driver core / ACPI: Avoid device hot remove locking issues

3 files changed, 46 insertions, 50 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e76365136ba3..61d090b6ce25 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -287,6 +287,7 @@ static void acpi_bus_device_eject(void *context)
         struct acpi_device *device = NULL;
         struct acpi_scan_handler *handler;
         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+        int error;
 
         mutex_lock(&acpi_scan_lock);
 
@@ -301,17 +302,13 @@ static void acpi_bus_device_eject(void *context)
         }
         acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
                                   ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
-        if (handler->hotplug.mode == AHM_CONTAINER) {
-                device->flags.eject_pending = true;
+        if (handler->hotplug.mode == AHM_CONTAINER)
                 kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
-        } else {
-                int error;
 
-                get_device(&device->dev);
-                error = acpi_scan_hot_remove(device);
-                if (error)
-                        goto err_out;
-        }
+        get_device(&device->dev);
+        error = acpi_scan_hot_remove(device);
+        if (error)
+                goto err_out;
 
  out:
         mutex_unlock(&acpi_scan_lock);
@@ -496,7 +493,6 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
         struct acpi_eject_event *ej_event;
         acpi_object_type not_used;
         acpi_status status;
-        u32 ost_source;
         int ret;
 
         if (!count || buf[0] != '1')
@@ -510,43 +506,28 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
         if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
                 return -ENODEV;
 
-        mutex_lock(&acpi_scan_lock);
-
-        if (acpi_device->flags.eject_pending) {
-                /* ACPI eject notification event. */
-                ost_source = ACPI_NOTIFY_EJECT_REQUEST;
-                acpi_device->flags.eject_pending = 0;
-        } else {
-                /* Eject initiated by user space. */
-                ost_source = ACPI_OST_EC_OSPM_EJECT;
-        }
         ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
         if (!ej_event) {
                 ret = -ENOMEM;
                 goto err_out;
         }
-        acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+        acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
                                   ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
         ej_event->device = acpi_device;
-        ej_event->event = ost_source;
+        ej_event->event = ACPI_OST_EC_OSPM_EJECT;
         get_device(&acpi_device->dev);
         status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
-        if (ACPI_FAILURE(status)) {
-                put_device(&acpi_device->dev);
-                kfree(ej_event);
-                ret = status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
-                goto err_out;
-        }
-        ret = count;
+        if (ACPI_SUCCESS(status))
+                return count;
 
- out:
-        mutex_unlock(&acpi_scan_lock);
-        return ret;
+        put_device(&acpi_device->dev);
+        kfree(ej_event);
+        ret = status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
 
  err_out:
-        acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+        acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
                                   ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
-        goto out;
+        return ret;
 }
 
 static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8856d74545d9..ac419a15fcd4 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -49,6 +49,28 @@ static struct kobject *dev_kobj;
 struct kobject *sysfs_dev_char_kobj;
 struct kobject *sysfs_dev_block_kobj;
 
+static DEFINE_MUTEX(device_hotplug_lock);
+
+void lock_device_hotplug(void)
+{
+        mutex_lock(&device_hotplug_lock);
+}
+
+void unlock_device_hotplug(void)
+{
+        mutex_unlock(&device_hotplug_lock);
+}
+
+int lock_device_hotplug_sysfs(void)
+{
+        if (mutex_trylock(&device_hotplug_lock))
+                return 0;
+
+        /* Avoid busy looping (5 ms of sleep should do). */
+        msleep(5);
+        return restart_syscall();
+}
+
 #ifdef CONFIG_BLOCK
 static inline int device_is_not_partition(struct device *dev)
 {
@@ -408,9 +430,9 @@ static ssize_t show_online(struct device *dev, struct device_attribute *attr,
 {
         bool val;
 
-        lock_device_hotplug();
+        device_lock(dev);
         val = !dev->offline;
-        unlock_device_hotplug();
+        device_unlock(dev);
         return sprintf(buf, "%u\n", val);
 }
 
@@ -424,7 +446,10 @@ static ssize_t store_online(struct device *dev, struct device_attribute *attr,
         if (ret < 0)
                 return ret;
 
-        lock_device_hotplug();
+        ret = lock_device_hotplug_sysfs();
+        if (ret)
+                return ret;
+
         ret = val ? device_online(dev) : device_offline(dev);
         unlock_device_hotplug();
         return ret < 0 ? ret : count;
@@ -1479,18 +1504,6 @@ EXPORT_SYMBOL_GPL(put_device);
 EXPORT_SYMBOL_GPL(device_create_file);
 EXPORT_SYMBOL_GPL(device_remove_file);
 
-static DEFINE_MUTEX(device_hotplug_lock);
-
-void lock_device_hotplug(void)
-{
-        mutex_lock(&device_hotplug_lock);
-}
-
-void unlock_device_hotplug(void)
-{
-        mutex_unlock(&device_hotplug_lock);
-}
-
 static int device_check_offline(struct device *dev, void *not_used)
 {
         int ret;
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 2b7813ec6d02..6f4c99ff1ce7 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -351,7 +351,9 @@ store_mem_state(struct device *dev,
 
         mem = container_of(dev, struct memory_block, dev);
 
-        lock_device_hotplug();
+        ret = lock_device_hotplug_sysfs();
+        if (ret)
+                return ret;
 
         if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) {
                 offline = false;