b8f7267d49
We already allow free(NULL) and uma_zfree(..., NULL). Make uma_zfree_pcpu(..., NULL) work as well. This also means that counter_u64_free(NULL) will work. These make cleanup code simpler. MFC after: 1 week Sponsored by: Rubicon Communications, LLC ("Netgate") Differential Revision: https://reviews.freebsd.org/D29189