Subject: Re: [PATCH 18/19] ibmvscsi: driver enablement for CMO

From: Brian King <[email-masked]>
Date: Fri, 13 Jun 2008 13:30:55 -0500

CC'ing linux-scsi, although we'd like to take this through the powerpc tree since it
is part of a patch set to enable a Power platform feature.

-Brian

Robert Jennings wrote:
> From: Robert Jennings <[email-masked]>
> 
> Enable the driver to function in a Cooperative Memory Overcommitment (CMO)
> environment.
> 
> The following changes are made to enable the driver for CMO:
>  * DMA mapping errors will not result in error messages if entitlement has
>    been exceeded and resources were not available.
>  * The driver has a get_io_entitlement function defined to function
>    in a CMO environment. It will indicate how much IO memory it would like
>    to function.
> 
> Signed-off-by: Robert Jennings <[email-masked]>
> 
> ---
>  drivers/scsi/ibmvscsi/ibmvscsi.c |   46 +++++++++++++++++++++++++++++++++------
>  drivers/scsi/ibmvscsi/ibmvscsi.h |    2 ++
>  2 files changed, 41 insertions(+), 7 deletions(-)
> 
> Index: b/drivers/scsi/ibmvscsi/ibmvscsi.c
> ===================================================================
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -72,6 +72,8 @@
>  #include <linux/delay.h>
>  #include <asm/firmware.h>
>  #include <asm/vio.h>
> +#include <asm/firmware.h>
> +#include <asm/iommu.h>
>  #include <scsi/scsi.h>
>  #include <scsi/scsi_cmnd.h>
>  #include <scsi/scsi_host.h>
> @@ -426,8 +428,10 @@ static int map_sg_data(struct scsi_cmnd 
>  					   SG_ALL * sizeof(struct srp_direct_buf),
>  					   &evt_struct->ext_list_token, 0);
>  		if (!evt_struct->ext_list) {
> -			sdev_printk(KERN_ERR, cmd->device,
> -				    "Can't allocate memory for indirect table\n");
> +			if (!firmware_has_feature(FW_FEATURE_CMO))
> +				sdev_printk(KERN_ERR, cmd->device,
> +				            "Can't allocate memory "
> +				            "for indirect table\n");
>  			return 0;
>  		}
>  	}
> @@ -743,7 +747,9 @@ static int ibmvscsi_queuecommand(struct 
>  	srp_cmd->lun = ((u64) lun) << 48;
> 
>  	if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) {
> -		sdev_printk(KERN_ERR, cmnd->device, "couldn't convert cmd to srp_cmd\n");
> +		if (!firmware_has_feature(FW_FEATURE_CMO))
> +			sdev_printk(KERN_ERR, cmnd->device,
> +			            "couldn't convert cmd to srp_cmd\n");
>  		free_event_struct(&hostdata->pool, evt_struct);
>  		return SCSI_MLQUEUE_HOST_BUSY;
>  	}
> @@ -855,7 +861,10 @@ static void send_mad_adapter_info(struct
>  					    DMA_BIDIRECTIONAL);
> 
>  	if (dma_mapping_error(req->buffer)) {
> -		dev_err(hostdata->dev, "Unable to map request_buffer for adapter_info!\n");
> +		if (!firmware_has_feature(FW_FEATURE_CMO))
> +			dev_err(hostdata->dev,
> +			        "Unable to map request_buffer for "
> +			        "adapter_info!\n");
>  		free_event_struct(&hostdata->pool, evt_struct);
>  		return;
>  	}
> @@ -1400,7 +1409,9 @@ static int ibmvscsi_do_host_config(struc
>  						    DMA_BIDIRECTIONAL);
> 
>  	if (dma_mapping_error(host_config->buffer)) {
> -		dev_err(hostdata->dev, "dma_mapping error getting host config\n");
> +		if (!firmware_has_feature(FW_FEATURE_CMO))
> +			dev_err(hostdata->dev,
> +			        "dma_mapping error getting host config\n");
>  		free_event_struct(&hostdata->pool, evt_struct);
>  		return -1;
>  	}
> @@ -1604,7 +1615,7 @@ static struct scsi_host_template driver_
>  	.eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
>  	.slave_configure = ibmvscsi_slave_configure,
>  	.change_queue_depth = ibmvscsi_change_queue_depth,
> -	.cmd_per_lun = 16,
> +	.cmd_per_lun = IBMVSCSI_CMDS_PER_LUN_DEFAULT,
>  	.can_queue = IBMVSCSI_MAX_REQUESTS_DEFAULT,
>  	.this_id = -1,
>  	.sg_tablesize = SG_ALL,
> @@ -1613,6 +1624,26 @@ static struct scsi_host_template driver_
>  };
> 
>  /**
> + * ibmvscsi_get_io_entitlement - Calculate IO entitlement needed by the driver
> + *
> + * @vdev: struct vio_dev for the device whose entitlement is to be returned
> + *
> + * Return value:
> + *	Number of bytes of IO data the driver will need to perform well.
> + */
> +static unsigned long ibmvscsi_get_io_entitlement(struct vio_dev *vdev)
> +{
> +	/* iu_storage data allocated in initialize_event_pool */
> +	unsigned long io_entitlement = max_requests * sizeof(union viosrp_iu);
> +
> +	/* add io space for sg data */
> +	io_entitlement += (IBMVSCSI_MAX_SECTORS_DEFAULT *
> +	                     IBMVSCSI_CMDS_PER_LUN_DEFAULT);
> +
> +	return IOMMU_PAGE_ALIGN(io_entitlement);
> +}
> +
> +/**
>   * Called by bus code for each adapter
>   */
>  static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
> @@ -1641,7 +1672,7 @@ static int ibmvscsi_probe(struct vio_dev
>  	hostdata->host = host;
>  	hostdata->dev = dev;
>  	atomic_set(&hostdata->request_limit, -1);
> -	hostdata->host->max_sectors = 32 * 8; /* default max I/O 32 pages */
> +	hostdata->host->max_sectors = IBMVSCSI_MAX_SECTORS_DEFAULT;
> 
>  	rc = ibmvscsi_ops->init_crq_queue(&hostdata->queue, hostdata, max_requests);
>  	if (rc != 0 && rc != H_RESOURCE) {
> @@ -1735,6 +1766,7 @@ static struct vio_driver ibmvscsi_driver
>  	.id_table = ibmvscsi_device_table,
>  	.probe = ibmvscsi_probe,
>  	.remove = ibmvscsi_remove,
> +	.get_io_entitlement = ibmvscsi_get_io_entitlement,
>  	.driver = {
>  		.name = "ibmvscsi",
>  		.owner = THIS_MODULE,
> Index: b/drivers/scsi/ibmvscsi/ibmvscsi.h
> ===================================================================
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.h
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.h
> @@ -45,6 +45,8 @@ struct Scsi_Host;
>  #define MAX_INDIRECT_BUFS 10
> 
>  #define IBMVSCSI_MAX_REQUESTS_DEFAULT 100
> +#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
> 
>  /* ------------------------------------------------------------
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-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center