[dm-devel] [PATCH v2 10/17] libmultipath: add code to get vendor specific vpd data

[Martin Wilck]

On Wed, 2020-02-05 at 12:58 -0600, Benjamin Marzinski wrote:
> This adds the wildcard 'g' for multipath and path formatted printing,
> which returns extra data from a device's vendor specific vpd
> page.  The
> specific vendor vpd page to use, and the vendor/product id to decode
> it
> can be set in the hwentry with vpd_vendor_pg and vpd_vendor_id. It
> can
> be configured in the devices section of multipath.conf with the
> vpd_vendor parameter. Currently, the only devices that use this are
> HPE
> 3PAR arrays, to return the Volume Name.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> ---
>  libmultipath/config.c      |  2 ++
>  libmultipath/config.h      |  1 +
>  libmultipath/dict.c        | 38 ++++++++++++++++++++++++++++++++++++
>  libmultipath/discovery.c   | 40
> +++++++++++++++++++++++++++++++++++++-
>  libmultipath/hwtable.c     |  1 +
>  libmultipath/print.c       | 25 ++++++++++++++++++++++++
>  libmultipath/propsel.c     | 18 +++++++++++++++++
>  libmultipath/propsel.h     |  1 +
>  libmultipath/structs.h     | 15 ++++++++++++++
>  multipath/multipath.conf.5 |  8 ++++++++
>  10 files changed, 148 insertions(+), 1 deletion(-)
> 
> diff --git a/libmultipath/structs.h b/libmultipath/structs.h
> index 1c32a799..6c03ee5d 100644
> --- a/libmultipath/structs.h
> +++ b/libmultipath/structs.h
> @@ -21,6 +21,7 @@
>  #define HOST_NAME_LEN		16
>  #define SLOT_NAME_SIZE		40
>  #define PRKEY_SIZE		19
> +#define VPD_DATA_SIZE		128
>  
>  #define SCSI_VENDOR_SIZE	9
>  #define SCSI_PRODUCT_SIZE	17
> @@ -221,6 +222,18 @@ enum all_tg_pt_states {
>  	ALL_TG_PT_ON = YNU_YES,
>  };
>  
> +enum vpd_vendor_ids {
> +	VPD_VP_UNDEF,
> +	VPD_VP_HP3PAR,
> +	VPD_VP_ARRAY_SIZE, /* This must remain the last entry */
> +};
> +
> +struct vpd_vendor_page {
> +	int pg;
> +	const char *name;
> +};
> +extern struct vpd_vendor_page vpd_vendor_pages[VPD_VP_ARRAY_SIZE];
> +
>  struct sg_id {
>  	int host_no;
>  	int channel;
> @@ -255,6 +268,7 @@ struct path {
>  	char rev[PATH_REV_SIZE];
>  	char serial[SERIAL_SIZE];
>  	char tgt_node_name[NODE_NAME_SIZE];
> +	char vpd_data[VPD_DATA_SIZE];


Hm, 128 more bytes per path for a rarely-used property... do we need to
store this in "struct path"? Can't we simply fetch that information
when someone requests it with the %g format wildcard? It doesn't matter
much today as "struct path" is really thick already, but I have hopes
to make it a bit leaner some day.

Regards
Martin

-- 
Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
SUSE  Software Solutions Germany GmbH
HRB 36809, AG Nürnberg GF: Felix
Imendörffer