From mboxrd@z Thu Jan 1 00:00:00 1970 From: Potnuri Bharat Teja Subject: Re: [PATCH 0/3] target: Fix queue-full callback error signaling Date: Mon, 3 Apr 2017 11:53:30 +0530 Message-ID: <20170403062329.GA13647@chelsio.com> References: <1477891554-26222-1-git-send-email-nab@linux-iscsi.org> <20170323053602.GA2323@chelsio.com> <1490934729.6977.27.camel@haakon3.risingtidesystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <1490934729.6977.27.camel@haakon3.risingtidesystems.com> Sender: target-devel-owner@vger.kernel.org To: "Nicholas A. Bellinger" Cc: target-devel , linux-rdma , SWise OGC , Sagi Grimberg List-Id: linux-rdma@vger.kernel.org On Friday, March 03/31/17, 2017 at 10:02:09 +0530, Nicholas A. Bellinger wrote: Hi Nicholas, > Hi Bharat & Co, > > On Thu, 2017-03-23 at 11:06 +0530, Potnuri Bharat Teja wrote: > > On Monday, October 10/31/16, 2016 at 10:55:51 +0530, Nicholas A. > Bellinger wrote: > > >    From: Nicholas Bellinger > > Hi Nicholas, > > This patch series fixes the post failures due to Send Queue overflow > when > > tested along with Sagi's "iser-target: avoid posting a recv buffer > twice", which > > goes on top of these 3 patches. > > > > Combined patches series(Nicholas's, Sagi's) works fine. > > Tested with iWARP iser. > > > > As these changes are critical for devices with lower sg resources, > hoping this > > series will be queued for next RC. > > > > Reviewed-by: Potnuri Bharat Teja > > Tested-by: Potnuri Bharat Teja > > As mentioned, the original three patches along with Sagi's have been > applied to target-pending/master. Thanks a lot! > > Thank you for your testing and patch review. > > I'm still considering if they should be CC'ed for stable, considering > AFAICT they are pretty much a requirement for iser-target to be stable > with iw_cxgb4.  It should be OK to include the series back to v4.1.y > stable, but I'm reviewing the target change again just to be sure. Yes, It would be nice to have them backported to v4.1 > > Also, I've been thinking a bit more about the hung tasks you reported > earlier during session reinstatement + repeated queue full preceding > Sagi's patch here: > > [1]http://www.spinics.net/lists/target-devel/msg14868.html > > and have some clarity as to what was going on.. > > The issue is that queue full handling for TFO->write_pending(), > TFO->queue_data_in() and TFO->queue_status failures will retry > indefinitely until they successfully complete, and currently do not > honor se_cmd quiesce that occurs during normal session reinstatement. > > Which means that if a fabric driver fails any of these three TFO > callbacks forever, the se_cmd descriptor will never be properly quiesced > back to fabric driver code, resulting in hung tasks you observed while > session shutdown waits for this action to complete. > > So as-is, this patch series doesn't address this particular scenario but > doesn't make it any worse either..  ;) > > That said, it's fine to merge this series now to allow iser-target + > iw_cxgb4 to function, and I'll be looking into addressing the infinite > queue_full + session reinstatement scenario for target-core in separate > patch series. Thanks, I shall get back to you with some more debug in the above scenario. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  [2]http://vger.kernel.org/majordomo-info.html > > References > > Visible links > 1. http://www.spinics.net/lists/target-devel/msg14868.html > 2. http://vger.kernel.org/majordomo-info.html