From: Gerd Hoffmann <kraxel@redhat.com>
To: Amit Shah <amit.shah@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 7/7] virtio: console: Return -EPIPE if port on the host isn't connected
Date: Tue, 23 Mar 2010 11:46:54 +0100 [thread overview]
Message-ID: <4BA89C1E.7090403@redhat.com> (raw)
In-Reply-To: <20100323091352.GI8675@amit-x200.redhat.com>
On 03/23/10 10:13, Amit Shah wrote:
>>> + if (use_multiport(port->portdev)&& !port->host_connected)
>>> + return -EPIPE;
>>> +
>>
>> Hmm, do applications actually handle this error?
>
> Don't know; there aren't any apps yet that use this functionality too.
Looks sensible to me.
> However, some error has to be indicated to the app otherwise it's just
> messy if the app keeps writing and receiving EAGAIN; we just get a tight
> loop in this case.
With poll support done right (don't signal "writable" when not
connected) this shouldn't be a issue. Apps retrying over and over
without waiting for the filehandle becoming writable are broken by design.
But apps can't disturgish between "ring full" and "host disconnected"
then. So think returning -EPIPE here isn't a bad choice.
cheers,
Gerd
next prev parent reply other threads:[~2010-03-23 10:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-23 8:57 [PATCH 0/7] virtio: console: Fixes, new flexible way of discovering ports Amit Shah
2010-03-23 8:57 ` [PATCH 1/7] MAINTAINERS: Put the virtio-console entry in correct alphabetical order Amit Shah
2010-03-23 8:57 ` [PATCH 2/7] virtio: console: Remove config work handler Amit Shah
2010-03-23 8:57 ` [PATCH 3/7] virtio: console: Add a __send_control_msg() that can send messages without a valid port Amit Shah
2010-03-23 8:57 ` [PATCH 4/7] virtio: console: Move code around for future patches Amit Shah
2010-03-23 8:57 ` [PATCH 5/7] virtio: console: Use a control message to add ports Amit Shah
2010-03-23 8:57 ` [PATCH 6/7] virtio: console: Don't always create a port 0 if using multiport Amit Shah
2010-03-23 8:58 ` [PATCH 7/7] virtio: console: Return -EPIPE if port on the host isn't connected Amit Shah
2010-03-23 9:00 ` Michael S. Tsirkin
2010-03-23 9:13 ` Amit Shah
2010-03-23 10:46 ` Gerd Hoffmann [this message]
2010-03-23 10:52 ` Amit Shah
2010-03-23 11:04 ` Gerd Hoffmann
2010-03-23 11:09 ` Amit Shah
2010-03-23 11:15 ` Gerd Hoffmann
2010-03-23 11:21 ` Amit Shah
2010-03-23 11:06 ` Amit Shah
2010-03-30 5:16 ` [PATCH 0/7] virtio: console: Fixes, new flexible way of discovering ports Rusty Russell
2010-03-30 5:20 ` Amit Shah
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