From: Paul Brook <paul@codesourcery.com>
To: Amit Shah <amit.shah@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>, qemu list <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH v3 2/4] char: Add ability to provide a callback when write won't return -EAGAIN
Date: Tue, 20 Apr 2010 13:28:48 +0100 [thread overview]
Message-ID: <201004201328.48953.paul@codesourcery.com> (raw)
In-Reply-To: <20100420114420.GA20123@amit-x200.redhat.com>
> I sent out this series as a "feeler" to see if the approach was
> acceptable.
>
> Paul didn't reply to my reply addressing his concern, so I take that as
> he's OK with the approach as well :-)
I'd probably exposed this as an asyncronous write rather than nonblocking
operation. However both have their issues and I guess for character devices
your approach makes sense (c.f. block devices where we want concurrent
transfers).
It would be useful to have a debugging mode where the chardev layer
deliberately returns spurious EAGAIN and short writes. Otherwise you've got a
lot of very poorly tested device fallback code. I have low confidence in
getting this right first time :-)
Paul
next prev parent reply other threads:[~2010-04-20 12:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-15 8:16 [Qemu-devel] [PATCH v3 0/4] char: write callback, virtio-console: flow control Amit Shah
2010-04-15 8:16 ` [Qemu-devel] [PATCH v3 1/4] char: Let writers know how much data was written in case of errors Amit Shah
2010-04-15 8:16 ` [Qemu-devel] [PATCH v3 2/4] char: Add ability to provide a callback when write won't return -EAGAIN Amit Shah
2010-04-15 8:16 ` [Qemu-devel] [PATCH v3 3/4] virtio-console: Factor out common init between console and generic ports Amit Shah
2010-04-15 8:16 ` [Qemu-devel] [PATCH v3 4/4] virtio-console: Throttle virtio-serial-bus if we can't consume any more guest data Amit Shah
2010-04-20 11:32 ` [Qemu-devel] [PATCH v3 2/4] char: Add ability to provide a callback when write won't return -EAGAIN Gerd Hoffmann
2010-04-20 11:44 ` Amit Shah
2010-04-20 12:28 ` Paul Brook [this message]
2010-04-20 12:39 ` Amit Shah
2010-04-20 18:59 ` Gerd Hoffmann
2010-04-15 12:04 ` [Qemu-devel] [PATCH v3 0/4] char: write callback, virtio-console: flow control Paul Brook
2010-04-15 12:58 ` Amit Shah
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