Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions

[Jes Sorensen <Jes.Sorensen@redhat.com>]

On 12/07/10 15:48, Michael Roth wrote:
> On 12/07/2010 07:31 AM, Jes Sorensen wrote:
>> On 12/03/10 19:03, Michael Roth wrote:
>>> This allows us to implement an i/o loop outside of vl.c that can
>>> interact with objects that use qemu_set_fd_handler()
>>>
>>> Signed-off-by: Michael Roth<mdroth@linux.vnet.ibm.com>
>>
>> This commit message really tells us nothing. Please be more specific
>> about what is in the commit.
>>
> 
> Currently, in qemu, the virtagent client/server functionality is driven
> by vl.c:main_loop_wait(), which implements a select() loop that kicks
> off handlers registered for various FDs/events via qemu_set_fd_handler().
> 
> To share the code with the agent, qemu-va.c, I re-implemented this i/o
> loop to do same thing, along with vl.c:qemu_set_fd_handler*() and
> friends. It was big nasty copy/paste job and I think most of the
> reviewers agreed that the i/o loop code should be shared.
> 
> This commit moves the shared code into back-end utility functions that
> get called by vl.c:qemu_set_fd_handler()/qemu_process_fd_handlers() and
> friends for qemu, and by
> qemu-tools.c:qemu_set_fd_handler()/qemu_process_fd_handlers() for tools.
> 
> So now to interact with code that uses qemu_set_fd_handler() you can
> built a select() loop around these utility functions.

Please put some of this in the commit message.

>> I am not happy with this addition of numbers to these functions, it
>> doesn't tell us why we have a 3 and how it differs from 2. If 3 is
>> really the backend for implementing 2, maybe it would be better to name
>> it __qemu_set_fd_handler2() and then have macros/wrappers calling into
>> it.
> 
> That was the initial plan, but qemu_set_fd_handler2() is a back-end of
> sorts for qemu_set_fd_handler(), so I was just trying to be consistent
> with the naming. Personally I don't have any objections one way or the
> other.

Anything to avoid qemu_set_fd_handler17() at some point. I think using
__qemu_set_fd_handler() encourages people to modify that code rather
than copy it.

Cheers,
Jes