From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753468AbdFMOJa (ORCPT ); Tue, 13 Jun 2017 10:09:30 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:7817 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752109AbdFMOJ2 (ORCPT ); Tue, 13 Jun 2017 10:09:28 -0400 Subject: Re: [PATCH 20/22] scsi: hisi_sas: Add v3 code to support ECC and AXI bus fatal error To: Arnd Bergmann References: <1495018197-120535-1-git-send-email-john.garry@huawei.com> <1495018197-120535-21-git-send-email-john.garry@huawei.com> <438a97a7-b424-a599-0c65-1e79dcdf8e86@huawei.com> CC: "James E.J. Bottomley" , "Martin K. Petersen" , John Garry , , , "Linux Kernel Mailing List" , Xiang Chen From: John Garry Message-ID: Date: Tue, 13 Jun 2017 15:05:30 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <438a97a7-b424-a599-0c65-1e79dcdf8e86@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.203.181.153] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.593FF138.026C,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 49cf5ff1da65f1133661263e21b4dc90 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/05/2017 13:38, John Garry wrote: > On 17/05/2017 13:27, Arnd Bergmann wrote: >> On Wed, May 17, 2017 at 12:49 PM, John Garry >> wrote: >>> > From: Xiang Chen >>> > >>> > For ECC 1bit error, logic can recover it, so we only print a warning. >>> > For ECC multi-bit and AXI bus fatal error, we panic. >>> > >>> > Signed-off-by: John Garry >>> > Signed-off-by: Xiang Chen >> This one is tricky as there are conflicting requirements: >> >> - For debugging purposes, you want to continue running the system >> to figure out what exactly went wrong. Often enough, having the >> kernel panic means you don't get to see the panic message because >> console access is unavailable and you cannot log in any more >> >> - For data consistency purposes you want to stop the system as >> soon as there is any uncorrectable data error >> >> I see that most scsi drivers don't ever call panic or BUG(), though >> you already do so for v1 and v2 hw. >> >> Maybe the SCSI maintainers can provide some more guidance here. >> >> Arnd >> >> . >> > > Hi Arnd, > > Actually latest code for v2 has been updated to do a controller reset, > and not panic, for unrecoverable error: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c?h=v4.12-rc1#n2926 > > > We never got around to implementing controller reset for v1 as this > platform (hip05) is not used much anymore. > > As for v3, we will change to to do same once controller reset is > implemented. I should have added this to the commit log. > > Thanks, > John It has come to light that hip08 RAS architecture requires handling certain errors with firmware first model. I am not sure on the flow of controller reset for fatal errors - I'm currently checking the details. But it is not worth adding this non-critical patch and reverting it later, so I'll omit this patch when sending the v6 patchset which includes the fix for sloppy spinlock usage. Thanks, John