[PATCH] nvmet: Don't queue fatal error work if csts.cfs is set

[Christoph Hellwig]

>  {
> -	ctrl->csts |= NVME_CSTS_CFS;
> +	if (test_and_set_bit(NVME_CSTS_CFS, (unsigned long *)&ctrl->csts))
> +		return;
> +

This can't work - test_and_set_bit takes a bit index and NVME_CSTS_CFS
is the actual value.  I think we'll need a lock to protect ->csts
instead.