From: Brian King <brking@linux.vnet.ibm.com>
Subject: Re: [PATCH 15/16 v3] ibmvscsi: driver enablement for CMO
Date: Mon, 07 Jul 2008 09:34:53 -0500
Message-ID: <4872298D.8050802@linux.vnet.ibm.com>
References: <20080704125631.GR1310@linux.vnet.ibm.com>
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In-Reply-To: <20080704125631.GR1310@linux.vnet.ibm.com>
Sender: linux-scsi-owner@vger.kernel.org
To: Robert Jennings <rcj@linux.vnet.ibm.com>
Cc: paulus@samba.org, linuxppc-dev@ozlabs.org, linux-scsi@vger.kernel.org, Santiago Leon <santil@us.ibm.com>, Nathan Fontenot <nfont@austin.ibm.com>, David Darrington <ddarring@linux.vnet.ibm.com>

Robert Jennings wrote:
> @@ -1613,6 +1624,26 @@ static struct scsi_host_template driver_
>  };
>  
>  /**
> + * ibmvscsi_get_desired_dma - 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_desired_dma(struct vio_dev *vdev)
> +{
> +	/* iu_storage data allocated in initialize_event_pool */
> +	unsigned long io_entitlement = max_requests * sizeof(union viosrp_iu);

Since you are removing the use of "entitlement" in the function description,
you should probably remove it everywhere in this patch.

> +
> +	/* add io space for sg data */
> +	io_entitlement += (IBMVSCSI_MAX_SECTORS_DEFAULT *
> +	                     IBMVSCSI_CMDS_PER_LUN_DEFAULT);
> +
> +	return IOMMU_PAGE_ALIGN(io_entitlement);

I really think this function should just return the number of bytes and
let the caller round it up to any boundary requirements it might have.

-Brian

-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center