Re: [PATCH v4 3/3] ibmvscsi: Allow to configure maximum LUN

[Hannes Reinecke]

On 11/09/2015 03:47 PM, Laurent Vivier wrote:
> This patch allows to define the maximum LUN numbers.
> As defined in 4.6.9 of SAM-4, the encoding of LUN is
> on 5 bits (max_lun=32) and the current value is only 8.
> 
> Signed-off-by: Laurent Vivier <lvivier@xxxxxxxxxx>
> ---
>  drivers/scsi/ibmvscsi/ibmvscsi.c | 9 ++++++++-
>  drivers/scsi/ibmvscsi/ibmvscsi.h | 1 +
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 04de287..adcd5e8 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -84,6 +84,7 @@
>   */
>  static int max_id = 64;
>  static int max_channel = 3;
> +static int max_lun = 8;
>  static int init_timeout = 300;
>  static int login_timeout = 60;
>  static int info_timeout = 30;
> @@ -117,6 +118,9 @@ module_param_named(fast_fail, fast_fail, int, S_IRUGO | S_IWUSR);
>  MODULE_PARM_DESC(fast_fail, "Enable fast fail. [Default=1]");
>  module_param_named(client_reserve, client_reserve, int, S_IRUGO );
>  MODULE_PARM_DESC(client_reserve, "Attempt client managed reserve/release");
> +module_param(max_lun, int, S_IRUGO);
> +MODULE_PARM_DESC(max_lun, "Maximum allowed LUN "
> +                          "[Default=8,Max="__stringify(IBMVSCSI_MAX_LUN)"]");
>  
>  static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
>  				struct ibmvscsi_host_data *hostdata);
> @@ -2289,7 +2293,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
>  		goto init_pool_failed;
>  	}
>  
> -	host->max_lun = 8;
> +	host->max_lun = max_lun;
>  	host->max_id = max_id;
>  	host->max_channel = max_channel;
>  	host->max_cmd_len = 16;
> @@ -2414,6 +2418,9 @@ int __init ibmvscsi_module_init(void)
>  {
>  	int ret;
>  
> +	if (max_lun > IBMVSCSI_MAX_LUN)
> +		return -EINVAL;
> +
>  	/* Ensure we have two requests to do error recovery */
>  	driver_template.can_queue = max_requests;
>  	max_events = max_requests + 2;
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h
> index 7d64867..1067367 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.h
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.h
> @@ -48,6 +48,7 @@ struct Scsi_Host;
>  #define IBMVSCSI_CMDS_PER_LUN_DEFAULT 16
>  #define IBMVSCSI_MAX_SECTORS_DEFAULT 256 /* 32 * 8 = default max I/O 32 pages */
>  #define IBMVSCSI_MAX_CMDS_PER_LUN 64
> +#define IBMVSCSI_MAX_LUN 32
>  
>  /* ------------------------------------------------------------
>   * Data Structures
> 
Please set max_lun to 31, and remove everything else.
As discussed, max_lun is the max number of LUNs supported by the
hardware/HBA. There is no point in restricting it further.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@xxxxxxx			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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