3 files changed, 32 insertions, 16 deletions

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;
diff --git a/include/linux/device.h b/include/linux/device.h
index 22b546a58591..545a04285120 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -895,6 +895,7 @@ static inline bool device_supports_offline(struct device *dev)
 
 extern void lock_device_hotplug(void);
 extern void unlock_device_hotplug(void);
+extern int lock_device_hotplug_sysfs(void);
 extern int device_offline(struct device *dev);
 extern int device_online(struct device *dev);
 /*