static void virtio_mem_run_wq()

in virtio_mem.c [2343:2423]

• 54 lines of code
• 15 McCabe index (conditional complexity)

static void virtio_mem_run_wq(struct work_struct *work)
{
	struct virtio_mem *vm = container_of(work, struct virtio_mem, wq);
	uint64_t diff;
	int rc;

	if (unlikely(vm->in_kdump)) {
		dev_warn_once(&vm->vdev->dev,
			     "unexpected workqueue run in kdump kernel\n");
		return;
	}

	hrtimer_cancel(&vm->retry_timer);

	if (vm->broken)
		return;

	atomic_set(&vm->wq_active, 1);
retry:
	rc = 0;

	/* Make sure we start with a clean state if there are leftovers. */
	if (unlikely(vm->unplug_all_required))
		rc = virtio_mem_send_unplug_all_request(vm);

	if (atomic_read(&vm->config_changed)) {
		atomic_set(&vm->config_changed, 0);
		virtio_mem_refresh_config(vm);
	}

	/* Unplug any leftovers from previous runs */
	if (!rc)
		rc = virtio_mem_unplug_pending_mb(vm);

	if (!rc && vm->requested_size != vm->plugged_size) {
		if (vm->requested_size > vm->plugged_size) {
			diff = vm->requested_size - vm->plugged_size;
			rc = virtio_mem_plug_request(vm, diff);
		} else {
			diff = vm->plugged_size - vm->requested_size;
			rc = virtio_mem_unplug_request(vm, diff);
		}
	}

	switch (rc) {
	case 0:
		vm->retry_timer_ms = VIRTIO_MEM_RETRY_TIMER_MIN_MS;
		break;
	case -ENOSPC:
		/*
		 * We cannot add any more memory (alignment, physical limit)
		 * or we have too many offline memory blocks.
		 */
		break;
	case -ETXTBSY:
		/*
		 * The hypervisor cannot process our request right now
		 * (e.g., out of memory, migrating);
		 */
	case -EBUSY:
		/*
		 * We cannot free up any memory to unplug it (all plugged memory
		 * is busy).
		 */
	case -ENOMEM:
		/* Out of memory, try again later. */
		hrtimer_start(&vm->retry_timer, ms_to_ktime(vm->retry_timer_ms),
			      HRTIMER_MODE_REL);
		break;
	case -EAGAIN:
		/* Retry immediately (e.g., the config changed). */
		goto retry;
	default:
		/* Unknown error, mark as broken */
		dev_err(&vm->vdev->dev,
			"unknown error, marking device broken: %d\n", rc);
		vm->broken = true;
	}

	atomic_set(&vm->wq_active, 0);
}