[PATCH 00/10] (v5) virtio: console: Fixes, new way of discovering ports

[Amit Shah <amit.shah@redhat.com>]

Hello,

This patchset is still based on Linus' tree but I'll rebase when Rusty
sends out the disable multiport patches.

This series reworks the ABI to allow port discovery (only) via the
control queue.

In addition, it adds support for non-blocking write() support, which
means no spinning. This works fine with the recent patches that are on
qemu-devel.

Also included is removal of hvc_remove() as removing one such console
port causes other console ports (registered with hvc) to stall. This
has to be debugged in the hvc_console.c file, I'll do that later, but
we have a nice workaround for this: returning -EPIPE on any hvc
operations will make the hvc console core perform any cleanups for the
removed ports. Looks like we don't lose much by removing hvc_remove().

New in this version:
- Complete support for non-blocking write()
- Don't call hvc_remove()
- Return -EPIPE for hvc operations if a console port was
  hot-unplugged.

Amit Shah (10):
  virtio: console: Add a __send_control_msg() that can send messages
    without a valid port
  virtio: console: Let host know of port or device add failures
  virtio: console: Return -EPIPE to hvc_console if we lost the
    connection
  virtio: console: Don't call hvc_remove() on unplugging console ports
  virtio: console: Remove config work handler
  virtio: console: Move code around for future patches
  virtio: console: Use a control message to add ports
  virtio: console: Don't always create a port 0 if using multiport
  virtio: console: Rename wait_is_over() to will_read_block()
  virtio: console: Add support for nonblocking write()s

 drivers/char/virtio_console.c  |  533 +++++++++++++++++++++-------------------
 include/linux/virtio_console.h |   18 +-
 2 files changed, 288 insertions(+), 263 deletions(-)