From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shiraz Saleem Subject: Re: [PATCH rdma-next] Revert "IB/core: Add flow control to the portmapper netlink calls" Date: Fri, 2 Jun 2017 11:28:49 -0500 Message-ID: <20170602162849.GA28660@ssaleem-MOBL4.amr.corp.intel.com> References: <20170529082423.1180-1-leon@kernel.org> <20170530212431.GA21008@ssaleem-MOBL4.amr.corp.intel.com> <20170531040437.GE5406@mtr-leonro.local> <20170531174245.GA16304@ssaleem-MOBL4.amr.corp.intel.com> <1496261429.2608.15.camel@sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1496261429.2608.15.camel-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche Cc: "leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "Latif, Faisal" , "leonro-Nfu5REtnQAJWk0Htik3J/w@public.gmane.org" , "Ismail, Mustafa" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On Wed, May 31, 2017 at 02:10:31PM -0600, Bart Van Assche wrote: > On Wed, 2017-05-31 at 12:42 -0500, Shiraz Saleem wrote: > > > 5. I proposed a solution -> go and fix your user space program. > > > > This is a kernel patch you are trying to revert, you are breaking existing > > kernel functionality. Nothing to do with user space. > > > > Bottom line, come up with a solution that will address both port mapper > > functionality and your issue. > > Hello Shiraz, > > Sorry that this means additional work for you, but I agree with Leon that > user space software should not assume that netlink sockets are a reliable > communication mechanism. Hi Bart - Thank you for your response. The original problem was that ibnl_unicast, which is used to send nl messages from portmapper kernel space to user-space, would occasionally and momentarily fail under stress. We could have retried the call for a certain amount of time, but since netlink_unicast has a nonblock/block parameter, we chose to use the blocking option with a timeout. So we thought we did account for deadlocks with this timeout. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html