From mboxrd@z Thu Jan 1 00:00:00 1970 From: dingxiang Subject: Re: [PATCH V2 resend] libata:fix kernel panic when hotplug Date: Wed, 22 Jun 2016 14:46:24 +0800 Message-ID: <576A3440.9090803@huawei.com> References: <1466052340-25520-1-git-send-email-dingxiang@huawei.com> <20160616202045.GF3262@mtj.duckdns.org> <20160621154700.GH3262@mtj.duckdns.org> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160621154700.GH3262@mtj.duckdns.org> Sender: linux-kernel-owner@vger.kernel.org To: Tejun Heo , Dan Williams Cc: "Martin K. Petersen" , jejb@linux.vnet.ibm.com, Wei Fang , miaoxie@huawei.com, wangyijing@huawei.com, zhangaihua1@huawei.com, zhaohongjiang@huawei.com, houtao1@huawei.com, linux-scsi , "linux-kernel@vger.kernel.org" List-Id: linux-scsi@vger.kernel.org Hi,All > Hello, > > On Mon, Jun 20, 2016 at 06:46:55PM -0700, Dan Williams wrote: >> On Mon, Jun 20, 2016 at 6:22 PM, Martin K. Petersen >> wrote: >>>>>>>> "Tejun" == Tejun Heo writes: >>>>> In fact,we don't need libata to deal with hotplug in sas environment. >>>>> So we can't run ata hotplug task when ata port is sas host. >>> Tejun> Martin, can you please confirm whether the above is true. If so, >>> Tejun> I'll route the patch through libata w/ stable cc'd. >>> >>> Not exactly a libsas expert. James? Dan? >> While it is true that libsas itself handles adding / removing devices >> we have historically avoided this conflict because >> ATA_PFLAG_SCSI_HOTPLUG is never set for libsas ata_ports. So the bug >> / behavior change is that ATA_PFLAG_SCSI_HOTPLUG gets set in the >> first place. Ignoring it is a band-aid / not the real fix afaics. > I see. I'll hold off for now then. Ding Xiang, can you find out > where that flag is getting set? > > Thanks! There are two places will set flag ATA_PFLAG_SCSI_HOTPLUG in libata-eh.c. I think both places should be protected. Here is the suggestion. Thanks~ diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index 61dc7a9..2bee041 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -1385,7 +1385,8 @@ void ata_eh_detach_dev(struct ata_device *dev) if (ata_scsi_offline_dev(dev)) { dev->flags |= ATA_DFLAG_DETACHED; - ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG; + if (!(ap->pflags & ATA_FLAG_SAS_HOST)) + ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG; } /* clear per-dev EH info */ @@ -3299,7 +3300,8 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link, } spin_lock_irqsave(ap->lock, flags); - ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG; + if (!(ap->pflags & ATA_FLAG_SAS_HOST)) + ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG; spin_unlock_irqrestore(ap->lock, flags); /* new device discovered, configure xfermode */