From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753868AbcJDHs0 (ORCPT ); Tue, 4 Oct 2016 03:48:26 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43925 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753778AbcJDHsZ (ORCPT ); Tue, 4 Oct 2016 03:48:25 -0400 Date: Tue, 4 Oct 2016 09:20:15 +0200 From: Greg KH To: Andy Grover Cc: snitzer@redhat.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/9] Generate uevents for all DM events Message-ID: <20161004072015.GA11216@kroah.com> References: <1475522580-16723-1-git-send-email-agrover@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1475522580-16723-1-git-send-email-agrover@redhat.com> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 03, 2016 at 12:22:51PM -0700, Andy Grover wrote: > Hi Mike and GregKH, > > I want a way to get devicemapper events without using the DM ioctl, > because that requires creating a thread to sleep in the ioctl for each > dm device I want events from. > > It would seem like using uevents and KOBJ_CHANGE would be a good way > to do this, but Mike said that the uevent maintainers (Greg that's > you?) did not think this was a good idea? KBOJ_CHANGE is a tricky one. It has been used for a variety of different things, but usually it is used to show that a major change has happened with a device like a docking station plug in or out. How often do DM events happen? What is triggering them? How do you want to send them to userspace? Through a sysfs file? Why not just use your own netlink connection? thanks, greg k-h