From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [PATCH] mpt2sas: don't handle broadcast primitives Date: Wed, 24 Jul 2013 15:23:57 -0400 Message-ID: <20130724192357.GC3641@logfs.org> References: <20130719220659.GF29404@logfs.org> <20130719221143.GG29404@logfs.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Baruch Even Cc: Nagalakshmi Nandigama , Sreekanth Reddy , Support , "James E.J. Bottomley" , DL-MPTFusionLinux@lsi.com, linux-scsi , linux-kernel@vger.kernel.org, mit@purestorage.com List-Id: linux-scsi@vger.kernel.org On Wed, 24 July 2013 23:42:22 +0300, Baruch Even wrote: > On Sat, Jul 20, 2013 at 1:11 AM, J=C3=B6rn Engel wr= ote: > > On Fri, 19 July 2013 18:06:59 -0400, J=C3=B6rn Engel wrote: > >> > >> The handling of broadcast primitives involves > >> _scsih_block_io_all_device(), which does what the name implies. I= have > >> observed cases with >60s of blocking io on all devices, caused by = a > >> single bad device. The downsides of this code are obvious, while = the > >> upsides are more elusive. > > > > And since this patch looks more like an April fools joke: I have > > gathered a few machine-months of testing, including tortures that > > specifically stress the removed codepaths. This is a serious > > submission and unless someone can show me a _very_ good reason for > > keeping the deleted code, I would like to get it merged. >=20 > This would seem to cause an IO pause through the host whenever there > is a disk removal/insertion or SES (SAS expander) change which seems > like a bad proposition indeed. The part of the work that this code > seems to handle is that when such a change happens something needs to > detect the dead IOs (f.ex. surprise disk removal) but I believe that > the SAS HBA firmware will do that internally already so I do think > this code is needless. >=20 > The only thing I'd like not to lose is the actual notification and > ability to log the fact that there was a broadcast notification on th= e > SAS network. I agree logging would be nice. However my attempts to keep logging and remove the IO pause were unsuccessful. Apparently something inside _scsih_sas_broadcast_primitive_event() is required to get future events. If someone from LSI with data sheets and understanding of the firmware can do a better patch, I would be happy. J=C3=B6rn -- The story so far: In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move. -- Douglas Adams