From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Subject: Re: Netlink messages without NLM_F_REQUEST flag
Date: Wed, 7 Jun 2017 12:35:11 -0600
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To: Leon Romanovsky <leon@kernel.org>
Cc: Kaike Wan <kaike.wan@intel.com>, John Fleck <john.fleck@intel.com>, Ira Weiny <ira.weiny@intel.com>, Thomas Graf <tgraf@suug.ch>, Doug Ledford <dledford@redhat.com>, Jiri Pirko <jiri@mellanox.com>, RDMA mailing list <linux-rdma@vger.kernel.org>, linux-netdev <netdev@vger.kernel.org>
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On Wed, Jun 07, 2017 at 09:18:10PM +0300, Leon Romanovsky wrote:

> > AFAIK, that is different, that is acking and retriggering a single shot
> > notification, not completing a kernel initiated handshake.
> 
> It is acking that message from user was received by kernel and now
> processing.

But isn't what is cared about here - the SA thing needs to send a
request to user space and collect a reply, it runs the protocol
backwards from normal.

It is not a notification because the request actually needs a reply,
and ACK's don't help because the reply has content.

It does not use the NOTIFICATION/REQUEST/REPLY sequence because it
does not care about reliability of delivering the REQUEST to user
space.

Jason