From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752762Ab2GQIBk (ORCPT ); Tue, 17 Jul 2012 04:01:40 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:38675 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750764Ab2GQIBe (ORCPT ); Tue, 17 Jul 2012 04:01:34 -0400 Message-ID: <1342511100.3039.9.camel@dabdike.int.hansenpartnership.com> Subject: Re: [PATCH] sd: do not set changed flag on all unit attention conditions From: James Bottomley To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Date: Tue, 17 Jul 2012 08:45:00 +0100 In-Reply-To: <50044D56.6000400@redhat.com> References: <1342454772-9018-1-git-send-email-pbonzini@redhat.com> <1342455503.3176.42.camel@dabdike.int.hansenpartnership.com> <50044D56.6000400@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-07-16 at 19:20 +0200, Paolo Bonzini wrote: > Il 16/07/2012 18:18, James Bottomley ha scritto: > >> > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > >> > index b583277..6d8ca08 100644 > >> > --- a/drivers/scsi/scsi_lib.c > >> > +++ b/drivers/scsi/scsi_lib.c > >> > @@ -843,8 +843,11 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) > >> > } else if (sense_valid && !sense_deferred) { > >> > switch (sshdr.sense_key) { > >> > case UNIT_ATTENTION: > >> > - if (cmd->device->removable) { > >> > - /* Detected disc change. Set a bit > >> > + if (cmd->device->removable && > >> > + (sshdr.asc == 0x3a || > >> > + (sshdr.asc == 0x28 && sshdr.ascq == 0x00))) { > >> > + /* "No medium" or "Medium may have changed." > >> > + * This means a disc change. Set a bit > > This type of change would likely cause a huge cascade of errors in real > > removable media devices. Under the MMC standards, which a lot of the > > older removable discs seem to follow, UNIT ATTENTION indicates either > > medium change or device reset (which we check for and eat lower down); > > we can't rely on them giving proper SBC-2 sense codes. If you want to > > pretend to be removable media, you have to conform to its standards. > > Would you accept a patch doing the opposite, i.e. passing some sense > codes such as PARAMETERS CHANGED and TARGET OPERATING CONDITIONS HAVE > CHANGED? Could you explain what the problem actually is? It looks like you had a reason to mark virtio-scsi as removable, even though it isn't, and now you want to add further hacks because being removable doesn't quite work. Lets go back and see if there's a more correct way to do whatever it is you want to do. James