Re: [PATCHv3 2/2] nvme: Expose cntrltype and dctype through sysfs

[Hannes Reinecke <hare@suse.de>]

On 2/8/22 20:33, Martin Belanger wrote:
> From: Martin Belanger <martin.belanger@dell.com>
> 
> TP8010 introduces the Discovery Controller Type attribute (dctype).
> The dctype is returned in the response to the Identify command. This
> patch exposes the dctype through the sysfs. Since the dctype depends on
> the Controller Type (cntrltype), another attribute of the Identify
> response, the patch also exposes the cntrltype as well. The dctype will
> only be displayed for discovery controllers.
> 
> A note about the naming of this attribute:
> Although TP8010 calls this attribute the Discovery Controller Type,
> note that the dctype is now part of the response to the Identify
> command for all controller types. I/O, Discovery, and Admin controllers
> all share the same Identify response PDU structure. Non-discovery
> controllers as well as pre-TP8010 discovery controllers will continue
> to set this field to 0 (which has always been the default for reserved
> bytes). Per TP8010, the value 0 now means "Discovery controller type is
> not reported" instead of "Reserved". One could argue that this
> definition is correct even for non-discovery controllers, and by
> extension, exposing it in the sysfs for non-discovery controllers is
> appropriate.
> 
> Signed-off-by: Martin Belanger <martin.belanger@dell.com>
> ---
>   drivers/nvme/host/core.c | 39 +++++++++++++++++++++++++++++++++++++++
>   drivers/nvme/host/nvme.h |  3 +++
>   include/linux/nvme.h     | 10 +++++++++-
>   3 files changed, 51 insertions(+), 1 deletion(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer