linux-kernel - Re: virtio scsi host draft specification, v3

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110612075140.GB11941@redhat.com>
Date:	Sun, 12 Jun 2011 10:51:41 +0300
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Hannes Reinecke <hare@...e.de>
Cc:	Paolo Bonzini <pbonzini@...hat.com>,
	Linux Virtualization <virtualization@...ts.linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	qemu-devel <qemu-devel@...gnu.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Stefan Hajnoczi <stefanha@...ux.vnet.ibm.com>,
	Christoph Hellwig <chellwig@...hat.com>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>
Subject: Re: virtio scsi host draft specification, v3

On Fri, Jun 10, 2011 at 02:55:35PM +0200, Hannes Reinecke wrote:
> >Device operation: request queues
> >--------------------------------
> >
> >The driver queues requests to an arbitrary request queue, and they are
> >used by the device on that same queue.
> >
> What about request ordering?
> If requests are placed on arbitrary queues you'll inevitably run on
> locking issues to ensure strict request ordering.
> I would add here:
> 
> If a device uses more than one queue it is the responsibility of the
> device to ensure strict request ordering.

Maybe I misunderstand - how can this be the responsibility of
the device if the device does not get the information about
the original ordering of the requests?

For example, if the driver is crazy enough to put
all write requests on one queue and all barriers
on another one, how is the device supposed to ensure
ordering?

-- 
MST
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/