From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH] sd: use async_probe cookie to avoid deadlocks Date: Tue, 21 Mar 2017 16:32:23 +0100 Message-ID: <1d91c7fa-5b63-f92f-e285-06aae73d93f0@suse.de> References: <1490098475-21884-1-git-send-email-hare@suse.de> <1490101519.2412.13.camel@HansenPartnership.com> <1490103027.2602.5.camel@sandisk.com> <1490103238.2412.17.camel@HansenPartnership.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:54236 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757281AbdCUPcl (ORCPT ); Tue, 21 Mar 2017 11:32:41 -0400 In-Reply-To: <1490103238.2412.17.camel@HansenPartnership.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley , Bart Van Assche , "martin.petersen@oracle.com" Cc: "linux-scsi@vger.kernel.org" , "hck@suse.de" , "hare@suse.com" On 03/21/2017 02:33 PM, James Bottomley wrote: > On Tue, 2017-03-21 at 13:30 +0000, Bart Van Assche wrote: >> On Tue, 2017-03-21 at 09:05 -0400, James Bottomley wrote: >>> How does this preserve ordering? It looks like you have one cookie >>> per sdkp ... is there some sort of ordering guarantee I'm not >>> seeing? >> >> Hello James, >> >> Since the probe order depends on the order in which __async_probe() >> adds entries to the "pending" list, and since the order of the >> __async_probe() calls is not changed by this patch, shouldn't the >> probe order be preserved by this patch? > > I don't know: that's what I'm asking. I believe they complete in order > for a single domain. I thought ordering isn't preserved between > domains? So moving to multiple domains loses us ordering of disk > appearance. > Ah. But we don't move to multiple domains, now do we? We're just terminating the wait until _our_ probe is completed. It's not that we're having a individual probe domain per device... Unless I'm misunderstanding something... Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)