From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <53C37575.5030808@suse.de> Date: Mon, 14 Jul 2014 08:15:17 +0200 From: Hannes Reinecke MIME-Version: 1.0 To: "K. Y. Srinivasan" , jasowang@redhat.com, apw@canonical.com, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, ohering@suse.com, jbottomley@parallels.com, hch@infradead.org, linux-scsi@vger.kernel.org CC: stable@vger.kernel.org Subject: Re: [PATCH V3 1/7] Drivers: scsi: storvsc: Change the limits to reflect the values on the host References: <1405183684-23928-1-git-send-email-kys@microsoft.com> <1405183712-23967-1-git-send-email-kys@microsoft.com> In-Reply-To: <1405183712-23967-1-git-send-email-kys@microsoft.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 07/12/2014 06:48 PM, K. Y. Srinivasan wrote: > Hyper-V hosts can support multiple targets and multiple channels and larger number of > LUNs per target. Update the code to reflect this. With this patch we can correctly > enumerate all the paths in a multi-path storage environment. > > In this version of the patch I have addressed comments from > Christoph Hellwig > > Signed-off-by: K. Y. Srinivasan > Cc: > --- > drivers/scsi/storvsc_drv.c | 47 +++++++++++++++++++++++++++++--------------- > 1 files changed, 31 insertions(+), 16 deletions(-) > > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > index 9969fa1..8938b13 100644 > --- a/drivers/scsi/storvsc_drv.c > +++ b/drivers/scsi/storvsc_drv.c > @@ -330,17 +330,17 @@ static int storvsc_timeout = 180; > > static void storvsc_on_channel_callback(void *context); > > -/* > - * In Hyper-V, each port/path/target maps to 1 scsi host adapter. In > - * reality, the path/target is not used (ie always set to 0) so our > - * scsi host adapter essentially has 1 bus with 1 target that contains > - * up to 256 luns. > - */ > -#define STORVSC_MAX_LUNS_PER_TARGET 64 > -#define STORVSC_MAX_TARGETS 1 > -#define STORVSC_MAX_CHANNELS 1 > +#define STORVSC_MAX_LUNS_PER_TARGET 255 > +#define STORVSC_MAX_TARGETS 2 > +#define STORVSC_MAX_CHANNELS 8 > > +#define STORVSC_FC_MAX_LUNS_PER_TARGET 255 > +#define STORVSC_FC_MAX_TARGETS 128 > +#define STORVSC_FC_MAX_CHANNELS 8 > > +#define STORVSC_IDE_MAX_LUNS_PER_TARGET 64 > +#define STORVSC_IDE_MAX_TARGETS 1 > +#define STORVSC_IDE_MAX_CHANNELS 1 > > struct storvsc_cmd_request { > struct list_head entry; Limiting max_lun to 255 will make the driver to _not_ respond to LUNs higher than that; ie Well-known LUN won't work here. Also the SCSI stack will be using REPORT LUNS anyway since you're advertising SPC-2 compliance. So your driver runs into issues if Hyper-V would ever return more than 256 LUNs with the REPORT LUN command or if any of the LUNs has an addressing scheme other than '0x00'. I would suggest to raise this to the technical limit (ie the largest LUN which the _protocol_ supports) and let REPORT LUNS deal with the actual LUNs. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N�rnberg GF: J. Hawn, J. Guild, F. Imend�rffer, HRB 16746 (AG N�rnberg)