Re: [ndctl PATCH 3/7] libcxl: apply CXL_CAPACITY_MULTIPLIER to partition alignment field

[Ira Weiny <ira.weiny@intel.com>]

On Mon, Jan 03, 2022 at 12:16:14PM -0800, Schofield, Alison wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 
> The IDENTIFY mailbox command returns the partition alignment field
> expressed in multiples of 256 MB.

Interesting...

I don't think anyone is using this function just yet but this does technically
change the behavior of this function.

Will that break anyone or cxl-cli?

> Use CXL_CAPACITY_MULTIPLIER when
> returning this field.
> 
> This is in sync with all the other partitioning related fields using
> the multiplier.

To me the fact that this was not in bytes implies that the original API of
libcxl was intended to not convert these values.

Vishal may have an opinion.  Should these be in bytes or 'CXL Capacity' units
(ie 256MB's)?

I think I prefer bytes as well.

Ira

> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  cxl/lib/libcxl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
> index 715d8e4..85a6c0e 100644
> --- a/cxl/lib/libcxl.c
> +++ b/cxl/lib/libcxl.c
> @@ -1086,7 +1086,7 @@ CXL_EXPORT unsigned long long cxl_cmd_identify_get_partition_align(
>  	if (cmd->status < 0)
>  		return cmd->status;
>  
> -	return le64_to_cpu(id->partition_align);
> +	return le64_to_cpu(id->partition_align) * CXL_CAPACITY_MULTIPLIER;
>  }
>  
>  CXL_EXPORT unsigned int cxl_cmd_identify_get_label_size(struct cxl_cmd *cmd)
> -- 
> 2.31.1
>