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Message-ID: <5d9c3107-5d07-4fe8-9782-cefb8d058ab5@suse.de>
Date: Sat, 15 Jun 2024 11:07:14 +0200
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Subject: Re: [PATCH 08/14] scsi: fnic: Add functionality in fnic to support
 FDLS
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To: "Karan Tilak Kumar (kartilak)" <kartilak@cisco.com>,
 "Sesidhar Baddela (sebaddel)" <sebaddel@cisco.com>
Cc: "Arulprabhu Ponnusamy (arulponn)" <arulponn@cisco.com>,
 "Dhanraj Jhawar (djhawar)" <djhawar@cisco.com>,
 "Gian Carlo Boffa (gcboffa)" <gcboffa@cisco.com>,
 "Masa Kai (mkai2)" <mkai2@cisco.com>,
 "Satish Kharat (satishkh)" <satishkh@cisco.com>,
 "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
 "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
 "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20240610215100.673158-1-kartilak@cisco.com>
 <20240610215100.673158-9-kartilak@cisco.com>
 <f992c0f2-8f70-4dc0-b679-e522e3fd6101@suse.de>
 <SJ0PR11MB58966D39EFAAD206CAE0A313C3C32@SJ0PR11MB5896.namprd11.prod.outlook.com>
From: Hannes Reinecke <hare@suse.de>
In-Reply-To: <SJ0PR11MB58966D39EFAAD206CAE0A313C3C32@SJ0PR11MB5896.namprd11.prod.outlook.com>
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On 6/15/24 05:47, Karan Tilak Kumar (kartilak) wrote:
> On Tuesday, June 11, 2024 11:57 PM, Hannes Reinecke <hare@suse.de> wrote:
>>
>> On 6/10/24 23:50, Karan Tilak Kumar wrote:
>>> Add interfaces in fnic to use FDLS services.
>>> Modify link up and link down functionality to use FDLS.
>>> Replace existing interfaces to handle new functionality provided by
>>> FDLS.
>>> Modify data types of some data members to handle new functionality.
>>> Add processing of tports and handling of tports.
>>>
>>> Reviewed-by: Sesidhar Baddela <sebaddel@cisco.com>
>>> Reviewed-by: Arulprabhu Ponnusamy <arulponn@cisco.com>
>>> Reviewed-by: Gian Carlo Boffa <gcboffa@cisco.com>
>>> Signed-off-by: Karan Tilak Kumar <kartilak@cisco.com>
>>> ---
>>>    drivers/scsi/fnic/fdls_disc.c |  74 +++++
>>>    drivers/scsi/fnic/fip.c       |  27 +-
>>>    drivers/scsi/fnic/fnic.h      |  20 +-
>>>    drivers/scsi/fnic/fnic_fcs.c  | 498 ++++++++++++++++++++++++----------
>>>    drivers/scsi/fnic/fnic_main.c |  10 +-
>>>    drivers/scsi/fnic/fnic_scsi.c | 127 +++++++--
>>>    6 files changed, 587 insertions(+), 169 deletions(-)
>>>
>> This seems to not just _add_ the functionality to use FDLS, but rather _replace_ the existing
>> functionality with FDLS.
>> IE it seems that after this change the driver will always do FDLS, causing a possible service
>> interruption with existing setups.
>> Hmm?
> 
> Thanks for your review comments, Hannes.
> As I mentioned in the other patch comments, Cisco has been shipping an async driver based on FDLS
> for the past six years.
> The async driver is backward compatible and supports all the adapters that are supported by the
> existing upstream driver, and more.
> The async driver in fact overrides the upstream driver on our installations.
>
Ah. Good to know. Ever more a reason to have your driver upstreamed, then...


> On Cisco hardware, the best practice out in the field, is to update the driver to the async
> driver during OS installation itself.
> Due to this best practice, we have _not_ received any feedback from customers indicating an
> abnormal service interruption specifically due to the driver update.
> 
Ah. I wasn't aware of that.
So that's fine, then, and you can disregard my comments here.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich