netdev - Re: [PATCH v2 net-next 7/7] tcp: make tcp_sendmsg() aware of socket backlog

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Date:	Thu, 28 Apr 2016 22:19:22 -0700
From:	Alexei Starovoitov <ast@...com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Eric Dumazet <edumazet@...gle.com>,
	"David S . Miller" <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>,
	Soheil Hassas Yeganeh <soheil@...gle.com>,
	Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Subject: Re: [PATCH v2 net-next 7/7] tcp: make tcp_sendmsg() aware of socket
 backlog

On 4/28/16 10:05 PM, Eric Dumazet wrote:
> On Thu, 2016-04-28 at 21:43 -0700, Alexei Starovoitov wrote:
>
>>
>> I don't understand the logic completely, but isn't it
>> safer to do 'goto wait_for_memory;' here if we happened
>> to hit this in the middle of the loop?
>
> Well, the wait_for_memory pushes data, and could early return to user
> space with short writes (non blocking IO). This would break things...

I see. Right. My only concern was about restarting the loop
and msg_data_left(), since it's really hard to follow iov_iter logic.