From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH v3] tcp: ioctl type SIOCOUTQNSD returns amount of data
 not sent
Date: Thu, 10 Mar 2011 14:16:05 -0800 (PST)
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From: Hagen Paul Pfeifer <hagen@jauu.net>
Date: Thu, 10 Mar 2011 23:12:05 +0100

> * David Miller | 2011-03-09 14:09:51 [-0800]:
> 
>>From: Steffen Sledz <sledz@dresearch.de>
>>Date: Sun,  6 Mar 2011 20:59:55 +0100
>>
>>> From: Mario Schuknecht <m.schuknecht@dresearch.de>
>>> 
>>> In contrast to SIOCOUTQ which returns the amount of data sent
>>> but not yet acknowledged plus data not yet sent this patch only
>>> returns the data not sent.
>>> 
>>> For various methods of live streaming bitrate control it may
>>> be helpful to know how much data are in the tcp outqueue are
>>> not sent yet.
>>> 
>>> Signed-off-by: Mario Schuknecht <m.schuknecht@dresearch.de>
>>> Signed-off-by: Steffen Sledz <sledz@dresearch.de>
>>
>>Applied, thanks.
> 
> A little bit late - but why not using struct tcp_info for that? The
> information is already provided via getsockopt(TCP_INFO).

It's pretty heavy handed to copy that entire TCP_INFO struct into
userspace during every I/O sequence the application makes.