Staging: android: binder: Create dedicated workqueue for binder deferred work

Some drivers flush the global workqueue when closed. This would deadlock if
the last reference to the file was released from the binder.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/android/binder.c

@@ -48,6 +48,7 @@ static struct dentry *binder_debugfs_dir_entry_proc;
 static struct binder_node *binder_context_mgr_node;
 static uid_t binder_context_mgr_uid = -1;
 static int binder_last_id;
+static struct workqueue_struct *binder_deferred_workqueue;
 
 #define BINDER_DEBUG_ENTRY(name) \
 static int binder_##name##_open(struct inode *inode, struct file *file) \
@@ -3109,7 +3110,7 @@ binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer)
 	if (hlist_unhashed(&proc->deferred_work_node)) {
 		hlist_add_head(&proc->deferred_work_node,
 				&binder_deferred_list);
-		schedule_work(&binder_deferred_work);
+		queue_work(binder_deferred_workqueue, &binder_deferred_work);
 	}
 	mutex_unlock(&binder_deferred_lock);
 }
@@ -3552,6 +3553,10 @@ static int __init binder_init(void)
 {
 	int ret;
 
+	binder_deferred_workqueue = create_singlethread_workqueue("binder");
+	if (!binder_deferred_workqueue)
+		return -ENOMEM;
+
 	binder_debugfs_dir_entry_root = debugfs_create_dir("binder", NULL);
 	if (binder_debugfs_dir_entry_root)
 		binder_debugfs_dir_entry_proc = debugfs_create_dir("proc",