UMA zinit/zctor function error returning

[Bosko Milekic]

Brian Fundakowski Feldman wrote:
> <URL:http://green.homeunix.org/~green/uma_error_checking.patch>

  Good work, overall.  I've looked at it, here are comments:

  - in mb_ctor_mbuf(), you need to free the mbuf if mac_init_mbuf()
    failed, before you return error (SERIOUS).

  - return (0) should be "return 0" (STYLE).

  - in mb_ctor_pack(), you need to free the mbuf if mac_init_mbuf()
    failed, before you return error (SERIOUS).

  - you didn't make the change for keginit and you split out the
    init function types into init (for zones) and keginit (for kegs).
    However, keg inits should be able to fail too and it should
    probably be the SAME type as the zone init.  This is a mistake.
    It is especially a mistake since most zones actually use the
    keg init, not the zone init (by default).  Only if you add
    a secondary zone do you get to talk about zone inits.  Let me
    know if this isn't clear for you.

  - You seem to misunderstand where inits are called.  Refer to
    my netbuf paper at www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf
    (specifically the diagrams) to see where the zone init and keg inits
    are called; for example, I have no idea why you've now defined
    zero_keginit and zero_init, this makes no sense.  This part of the
    patch (including how you now cast to uma_keginit explicitly in
    zone_ctor) needs to be redone.  I don't think you should split up
    the init types (i.e., zone init and keg init have same types) and
    have both of them be able to fail.  I know you might find this
    tougher since you have to deal with freeing back to the slab from
    the keg code on allocation failure, but that complexity is part of
    this change's requirement.

  - the uma_dbg.c changes call the ctor explicitly from the fini.
    I forget the exact reason this is, but now that we're expecting
    the ctor to return something, if you are ignoring the return
    value, please cast void explicitly here (STYLE).  Alternately,
    make both keg and zone inits able to fail and propagate the failure,
    if any, upwards.

Regards,
-Bosko