From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 2/3] scsi: replace 'tag' with 'hba_private' pointer Date: Fri, 01 Jul 2011 15:11:01 +0200 Message-ID: <4E0DC765.5090200@suse.de> References: <1309506172-17762-1-git-send-email-hare@suse.de> <1309506172-17762-2-git-send-email-hare@suse.de> <1309506172-17762-3-git-send-email-hare@suse.de> <4E0D84DF.7030303@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: qemu-devel@nongnu.org, Stefan Haynoczi , kvm@vger.kernel.org, Alexander Graf To: Paolo Bonzini Return-path: Received: from cantor2.suse.de ([195.135.220.15]:58744 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755010Ab1GANLE (ORCPT ); Fri, 1 Jul 2011 09:11:04 -0400 In-Reply-To: <4E0D84DF.7030303@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 07/01/2011 10:27 AM, Paolo Bonzini wrote: > On 07/01/2011 09:42 AM, Hannes Reinecke wrote: >> 'tag' is just an abstraction to identify the command >> from the driver. So we should make that explicit by >> replacing 'tag' with a driver-defined pointer 'hba_private'. >> This saves the lookup for driver handling several commands >> in parallel. > > This makes tracing a bit harder to follow. Perhaps you can keep the > transport tag (a uint64_t) in the SCSIRequest for debugging purposes? > Hmm. The transport tag wouldn't have any meaning outside scsi-bus.c. And it's a 64-bit value. So why can't we use the hba_private pointer=20 directly here? After some I/O has been ongoing the linear 'tag' number becomes=20 unreadable very quickly, so there's not much difference here ... Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg)