static int virtio_mem_sbm_unplug_any_sb_online()

in virtio_mem.c [1958:2009]

• 39 lines of code
• 14 McCabe index (conditional complexity)

static int virtio_mem_sbm_unplug_any_sb_online(struct virtio_mem *vm,
					       unsigned long mb_id,
					       uint64_t *nb_sb)
{
	int rc, sb_id;

	/* If possible, try to unplug the complete block in one shot. */
	if (*nb_sb >= vm->sbm.sbs_per_mb &&
	    virtio_mem_sbm_test_sb_plugged(vm, mb_id, 0, vm->sbm.sbs_per_mb)) {
		rc = virtio_mem_sbm_unplug_sb_online(vm, mb_id, 0,
						     vm->sbm.sbs_per_mb);
		if (!rc) {
			*nb_sb -= vm->sbm.sbs_per_mb;
			goto unplugged;
		} else if (rc != -EBUSY)
			return rc;
	}

	/* Fallback to single subblocks. */
	for (sb_id = vm->sbm.sbs_per_mb - 1; sb_id >= 0 && *nb_sb; sb_id--) {
		/* Find the next candidate subblock */
		while (sb_id >= 0 &&
		       !virtio_mem_sbm_test_sb_plugged(vm, mb_id, sb_id, 1))
			sb_id--;
		if (sb_id < 0)
			break;

		rc = virtio_mem_sbm_unplug_sb_online(vm, mb_id, sb_id, 1);
		if (rc == -EBUSY)
			continue;
		else if (rc)
			return rc;
		*nb_sb -= 1;
	}

unplugged:
	/*
	 * Once all subblocks of a memory block were unplugged, offline and
	 * remove it. This will usually not fail, as no memory is in use
	 * anymore - however some other notifiers might NACK the request.
	 */
	if (virtio_mem_sbm_test_sb_unplugged(vm, mb_id, 0, vm->sbm.sbs_per_mb)) {
		mutex_unlock(&vm->hotplug_mutex);
		rc = virtio_mem_sbm_offline_and_remove_mb(vm, mb_id);
		mutex_lock(&vm->hotplug_mutex);
		if (!rc)
			virtio_mem_sbm_set_mb_state(vm, mb_id,
						    VIRTIO_MEM_SBM_MB_UNUSED);
	}

	return 0;
}