MFC: r201932

- Add code allowing a network device to only be open and closed once
  by keeping it opened after the first open and closing it via the
  cleanup handler when NETIF_OPEN_CLOSE_ONCE is defined in order to
  avoid the open-close-dance on every file access which with firmware
  that for example performs an auto-negotiation on every open causes
  netbooting to take horribly long. Basically the behavior with this
  knob enabled resembles the one employed between r60506 and r177108
  (and for sparc64 also again since r182919) with the addition that
  the network device now is closed eventually before entering the
  kernel and before rebooting. Actually I think this should be the
  desired MI behavior, however the U-Boot loader actually requires
  net_close() to be called after every transaction in order for some
  local shutdown operations to be performed (and which I think thus
  will break on concurrent opens, i.e. when netdev_opens is > 1, like
  the loader does at least for disks when LOADER_GZIP_SUPPORT is
  enabled).
- Use NETIF_OPEN_CLOSE_ONCE to replace the hack, which artificially
  increased netdev_opens for sparc64 in order to keep the network
  device opened forever, as at least some firmware versions require
  the network device to be closed eventually before entering the
  kernel or otherwise will DMA received packets to stale memory.
  The powerpc OFW loader probably wants NETIF_OPEN_CLOSE_ONCE to be
  set as well for the same reasons.

0 files changed, 0 insertions, 0 deletions