Re: [Qemu-devel] [PATCH 0/9] Clear fd handlers

[Anthony Liguori <anthony@codemonkey.ws>]

On 03/09/2010 05:53 PM, malc wrote:
> On Tue, 9 Mar 2010, Juan Quintela wrote:
>
>    
>> Hi
>>
>> This series :
>> - convert io_handlers to one QLIST
>> - once there, qemu_set_fd_handlers2() has lots of arguments that are a lot of times NULL.
>>    Introduce a set of functions to not have to pass NULL values.
>>   - qemu_clear_fd_handlers(): remove it
>>   - qemu_set_fd_read_handler(): only read
>>   - qemu_set_fd_write_handler(): only write
>>   - qemu_set_fd_rw_handler(): read/write
>>   - qemu_set_fd_poll_handler(): it was only used for reads and in qemu-char.c.
>>
>> - once there fix bt that don't need poll at all (having a poll function that always return true
>>    is the equivalent of not having one).
>> - remove cast to (void *)(unsigned long) for things that already were pointers
>> - IOCanRWHandler is only used for reads ->  rename it (almost no users).
>>
>> ToDo:
>> - to remove the export of qemu_set_fd_handlers2() we need a solution for tap.
>>    Tap is the only user in qemu that uses poll, read and write, and it changes in very imaginative
>>    ways:
>>      qemu_set_fd_handler2(s->fd,
>>                           s->read_poll  ? tap_can_send : NULL,
>>                           s->read_poll  ? tap_send     : NULL,
>>                           s->write_poll ? tap_writable : NULL,
>>                           s);
>>
>>    No ideas about how to transform this into something that don't use NULL's in any of its fields
>>    other than a row of if's.
>>
>> - removal of poll function. comment of qemu_set_fd_handler2()
>>    /* XXX: fd_read_poll should be suppressed, but an API change is
>>      necessary in the character devices to suppress fd_can_read(). */
>>
>>    But qemu-char.c is a complex beast, and would preffer to 1st get this patches in, and then
>>    work on the other stuff.
>>
>> - obvious optimization now is to have the FD_SET() for write/read already filled, but I
>>    haven't done any meassurement.
>>
>> Comments?
>>
>> Juan Quintela (9):
>>    Convert io handlers to QLIST
>>    Introduce qemu_clear_fd_handler()
>>    Introduce qemu_set_fd_read_handler()
>>    Introduce qemu_set_fd_write_handler()
>>    Introduce qemu_set_fd_rw_handler()
>>    bt: remove bt_host_read_poll()
>>    Introduce qemu_set_fd_poll_handler()
>>    remove useless cast
>>    rename IOCanRWHandler to IOCanReadHandler
>>
>>   aio.c               |    2 +-
>>   audio/alsaaudio.c   |   12 +++---
>>   audio/ossaudio.c    |   10 ++--
>>   bt-host.c           |    9 +----
>>   bt-vhci.c           |    2 +-
>>   hw/baum.c           |    2 +-
>>   hw/xen_backend.c    |   10 ++--
>>   migration-exec.c    |    8 ++--
>>   migration-fd.c      |    5 +-
>>   migration-tcp.c     |   10 ++--
>>   migration-unix.c    |   10 ++--
>>   migration.c         |    8 ++--
>>   net/socket.c        |   14 +++---
>>   net/vde.c           |    4 +-
>>   qemu-aio.h          |    4 +-
>>   qemu-char.c         |   48 +++++++++++-----------
>>   qemu-char.h         |   25 ++++++++---
>>   qemu-common.h       |    2 +-
>>   qemu-tool.c         |    9 ++--
>>   usb-linux.c         |    4 +-
>>   vl.c                |  114 +++++++++++++++++++++++++++++++++++---------------
>>   vnc-auth-sasl.c     |    2 +-
>>   vnc-auth-vencrypt.c |    6 +-
>>   vnc.c               |   12 +++---
>>   24 files changed, 190 insertions(+), 142 deletions(-)
>>      
> What's the point if it ends up adding 48 lines of code?
>    

Yeah, I think this would be more interesting if it eliminated the 
can_read handlers altogether.

Regards,

Anthony Liguori