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From: Max Reitz <mreitz@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <famz@redhat.com>,
	qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [RFC 3/5] nbd: Use aio_set_fd_handler2()
Date: Sat, 07 Jun 2014 21:27:26 +0200	[thread overview]
Message-ID: <5393679E.9080900@redhat.com> (raw)
In-Reply-To: <53917173.6060107@redhat.com>

On 06.06.2014 09:44, Paolo Bonzini wrote:
> Il 05/06/2014 20:18, Max Reitz ha scritto:
>>>
>>> Why is this design cleaner?  Because NBD code doesn't have to worry
>>> about fd handlers.  It uses straightforward coroutine send/recv for
>>> socket I/O inside nbd_read_req() and nbd_write_resp().  It's easy to 
>>> see
>>> that only one coroutine receives from the socket and that only one
>>> coroutine writes to the socket.
>>
>> Yes, this sounds better. I'll take a look into it and see how far I can
>> get.
>
> But it doesn't solve any problem, and requires rethinking the 
> aio_set_fd_handler API.

It might clean things up. :-)

On the other hand, you are right, it's probably too complicated right now.

> I suggest you just refactor all calls to qemu_set_fd_handler2 into a 
> function like
>
>     qemu_set_fd_handler2(fd, NULL,
>                  nbd_can_read(client) ? nbd_read : NULL,
>                  client->send_coroutine ?
>                     nbd_restart_write : NULL,
>                  opaque);
>
> and call this function every time the result of nbd_can_read() 
> changes.  Then you can switch to aio_set_fd_handler easily.

Seems good, I'll do that.

Max

  reply	other threads:[~2014-06-07 19:27 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1401561792-13410-1-git-send-email-mreitz@redhat.com>
2014-06-03 14:38 ` [Qemu-devel] [RFC 0/5] nbd: Adapt for dataplane Stefan Hajnoczi
2014-06-05 17:41   ` Max Reitz
     [not found] ` <1401561792-13410-3-git-send-email-mreitz@redhat.com>
2014-06-03 17:55   ` [Qemu-devel] [RFC 2/5] aio: Add io_read_poll() callback Paolo Bonzini
2014-06-05 17:29     ` Max Reitz
2014-06-04 11:59   ` Stefan Hajnoczi
     [not found] ` <1401561792-13410-2-git-send-email-mreitz@redhat.com>
2014-06-04 11:52   ` [Qemu-devel] [RFC 1/5] nbd: Correct name comparison for export_set_name() Stefan Hajnoczi
2014-06-05 17:28     ` Max Reitz
     [not found] ` <1401561792-13410-4-git-send-email-mreitz@redhat.com>
2014-06-04 12:37   ` [Qemu-devel] [RFC 3/5] nbd: Use aio_set_fd_handler2() Stefan Hajnoczi
2014-06-04 18:02     ` Paolo Bonzini
2014-06-05  8:12       ` Stefan Hajnoczi
2014-06-05  9:27         ` Paolo Bonzini
2014-06-05 13:32           ` Stefan Hajnoczi
2014-06-05 18:18     ` Max Reitz
2014-06-06  7:44       ` Paolo Bonzini
2014-06-07 19:27         ` Max Reitz [this message]
2014-06-09 13:35           ` Stefan Hajnoczi
     [not found] ` <1401561792-13410-5-git-send-email-mreitz@redhat.com>
2014-06-04 12:41   ` [Qemu-devel] [RFC 4/5] block: Add AIO followers Stefan Hajnoczi
2014-06-05 17:31     ` Max Reitz
     [not found] ` <538A3A8F.3060508@redhat.com>
2014-06-04 12:47   ` [Qemu-devel] [RFC 0/5] nbd: Adapt for dataplane Stefan Hajnoczi
2014-06-04 12:50 ` Stefan Hajnoczi

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