Catch up with Bryan Venteicher's virtio git repo:

a8af6270bd96be6ccd86f70b60fa6512b710e4f0
      virtio_blk: Include function name in panic string

cbdb03a694b76c5253d7ae3a59b9995b9afbb67a
      virtio_balloon: Do the notify outside of the lock

      By the time we return from virtqueue_notify(), the descriptor
      will be in the used ring so we shouldn't have to sleep.

10ba392e60692529a5cbc1e9987e4064e0128447
      virtio: Use DEVMETHOD_END

80cbcc4d6552cac758be67f0c99c36f23ce62110
      virtqueue: Add support for VIRTIO_F_RING_EVENT_IDX

      This can be used to reduce the number of guest/host and
      host/guest interrupts by delaying the interrupt until a
      certain index value is reached.

      Actual use by the network driver will come along later.

8fc465969acc0c58477153e4c3530390db436c02
      virtqueue: Simplify virtqueue_nused()

      Since the values just wrap naturally at UINT16_MAX, we
      can just subtract the two values directly, rather than
      doing 2's complement math.

a8aa22f25959e2767d006cd621b69050e7ffb0ae
      virtio_blk: Remove debugging crud from 75dd732a

      There seems to be an issue with Qemu (or FreeBSD VirtIO) that sets
      the PCI register space for the device config to bogus values. This
      only seems to happen after unloading and reloading the module.

d404800661cb2a9769c033f8a50b2133934501aa
      virtio_blk: Use better variable name

75dd732a97743d96e7c63f7ced3c2169696dadd3
      virtio_blk: Partially revert 92ba40e65

      Just use the virtqueue to determine if any requests are
      still inflight.

06661ed66b7a9efaea240f99f414c368f1bbcdc7
      virtio_blk: error if allowed too few segments

      Should never happen unless the host provides use with a
      bogus seg_max value.

4b33e5085bc87a818433d7e664a0a2c8f56a1a89
      virtio_blk: Sort function declarations

426b9f5cac892c9c64cc7631966461514f7e08c6
      virtio_blk: Cleanup whitespace

617c23e12c61e3c2233d942db713c6b8ff0bd112
      virtio_blk: Call disk_err() on error'd completed requests

081a5712d4b2e0abf273be4d26affcf3870263a9
      virtio_blk: ASSERT the ready and inflight request queues are empty

a9be2631a4f770a84145c18ee03a3f103bed4ca8
      virtio_blk: Simplify check for too many segments

      At the cost of a small style violation.

e00ec09da014f2e60cc75542d0ab78898672d521
      virtio_blk: Add beginnings of suspend/resume

      Still not sure if we need to virtio_stop()/virtio_reinit()
      the device before/after a suspend.

      Don't start additional IO when marked as suspending.

47c71dc6ce8c238aa59ce8afd4bda5aa294bc884
      virtio_blk: Panic when dealt an unhandled BIO cmd

1055544f90fb8c0cc6a2395f5b6104039606aafe
      virtio_blk: Add VQ enqueue/dequeue wrappers

      Wrapper functions managed the added/removing to the in-flight
      list of requests.

      Normally biodone() any completed IO when draining the virtqueue.

92ba40e65b3bb5e4acb9300ece711f1ea8f3f7f4
      virtio_blk: Add in-flight list of requests

74f6d260e075443544522c0833dc2712dd93f49b
      virtio_blk: Rename VTBLK_FLAG_DETACHING to VTBLK_FLAG_DETACH

7aa549050f6fc6551c09c6362ed6b2a0728956ef
      virtio_blk: Finish all BIOs through vtblk_finish_bio()

      Also properly set bio_resid in the case of errors. Most geom_disk
      providers seem to do the same.

9eef6d0e6f7e5dd362f71ba097f2e2e4c3744882
      Added function to translate VirtIO status to error code

ef06adc337f31e1129d6d5f26de6d8d1be27bcd2
      Reset dumping flag when given unexpected parameters

393b3e390c644193a2e392220dcc6a6c50b212d9
      Added missing VTBLK_LOCK() in dump handler

Obtained from:	Bryan Venteicher  bryanv at daemoninthecloset dot org