tcmu: split unmap_thread_fn

Separate unmap_thread_fn to make it easier to read.

Note: this patch does not fix the bug where we might
miss a wake up call. The next patch will fix that.
This patch only separates the code into functions.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_user.c

@@ -1973,22 +1973,13 @@ static struct target_backend_ops tcmu_ops = {
 	.tb_dev_attrib_attrs	= NULL,
 };
 
-static int unmap_thread_fn(void *data)
+
+static void find_free_blocks(void)
 {
 	struct tcmu_dev *udev;
 	loff_t off;
 	uint32_t start, end, block;
 
-	while (!kthread_should_stop()) {
-		DEFINE_WAIT(__wait);
-
-		prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE);
-		schedule();
-		finish_wait(&unmap_wait, &__wait);
-
-		if (kthread_should_stop())
-			break;
-
 	mutex_lock(&root_udev_mutex);
 	list_for_each_entry(udev, &root_udev, node) {
 		mutex_lock(&udev->cmdr_lock);
@@ -2028,16 +2019,45 @@ static int unmap_thread_fn(void *data)
 		tcmu_blocks_release(&udev->data_blocks, start, end);
 		mutex_unlock(&udev->cmdr_lock);
 	}
+	mutex_unlock(&root_udev_mutex);
+}
+
+static void run_cmdr_queues(void)
+{
+	struct tcmu_dev *udev;
 
 	/*
 	 * Try to wake up the udevs who are waiting
-		 * for the global data pool.
+	 * for the global data block pool.
 	 */
+	mutex_lock(&root_udev_mutex);
 	list_for_each_entry(udev, &root_udev, node) {
-			if (udev->waiting_global)
+		mutex_lock(&udev->cmdr_lock);
+		if (!udev->waiting_global) {
+			mutex_unlock(&udev->cmdr_lock);
+			break;
+		}
+		mutex_unlock(&udev->cmdr_lock);
+
 		wake_up(&udev->wait_cmdr);
 	}
 	mutex_unlock(&root_udev_mutex);
+}
+
+static int unmap_thread_fn(void *data)
+{
+	while (!kthread_should_stop()) {
+		DEFINE_WAIT(__wait);
+
+		prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE);
+		schedule();
+		finish_wait(&unmap_wait, &__wait);
+
+		if (kthread_should_stop())
+			break;
+
+		find_free_blocks();
+		run_cmdr_queues();
 	}
 
 	return 0;