[Qemu-devel] [PATCH v5 0/6] char: non-blocking writes, virtio-console flow control

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

Hello,

This series lets interested callers ask for an -EAGAIN return from the
chardev backends (only unix and tcp sockets as of now) to implement
their own flow control.

A new call, qemu_chr_write_nb() is added, that will fallback to
qemu_chr_write() if the backend file isn't non-blocking or if no
callback was supplied.

Support for other backend types is easy to add and will be done in
later patches.

v5:
- Fix bug pointed out by Gerd
- Convert to using a struct for passing on handlers to
  qemu_chr_add_handlers() instead of passing each one
  individually. Simplifies patches. (Inspired by Juan's comment)
- Re-arranged patches

Amit Shah (6):
  virtio-console: Factor out common init between console and generic
    ports
  char: Add a QemuChrHandlers struct to initialise chardev handlers
  char: Let writers know how much data was written in case of errors
  char: Add qemu_chr_write_nb() for nonblocking writes
  char: unix/tcp: Add a non-blocking write handler
  virtio-console: Throttle virtio-serial-bus if we can't consume any
    more guest data

 gdbstub.c            |    9 ++-
 hw/debugcon.c        |    2 +-
 hw/escc.c            |    9 ++-
 hw/etraxfs_ser.c     |   13 +++-
 hw/mcf_uart.c        |    9 ++-
 hw/pl011.c           |    9 ++-
 hw/pxa2xx.c          |   13 +++-
 hw/serial.c          |    9 ++-
 hw/sh_serial.c       |   12 +++-
 hw/syborg_serial.c   |    9 ++-
 hw/usb-serial.c      |    9 ++-
 hw/virtio-console.c  |  162 +++++++++++++++++++++++++++++++++++++++++++------
 hw/xen_console.c     |   16 ++++--
 hw/xilinx_uartlite.c |   11 +++-
 monitor.c            |   19 +++++-
 net/slirp.c          |    8 ++-
 net/socket.c         |    4 +-
 qemu-char.c          |  119 +++++++++++++++++++++++++++++++------
 qemu-char.h          |   20 +++++-
 qemu_socket.h        |    3 +-
 20 files changed, 381 insertions(+), 84 deletions(-)