Re: [PATCH 3/5] s390: Add a mechanism to get the subchannel id.

Alexander Graf
2012-12-09T12:12:37Z

On 07.12.2012, at 13:29, Cornelia Huck wrote:

> This will be needed by the new virtio-ccw transport.
>
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> ---
> arch/s390/include/asm/ccwdev.h | 5 +++++
> drivers/s390/cio/device_ops.c | 12 ++++++++++++
> 2 files changed, 17 insertions(+)
>
> diff --git a/arch/s390/include/asm/ccwdev.h b/arch/s390/include/asm/ccwdev.h
> index 1cb4bb3..9ad79f7 100644
> --- a/arch/s390/include/asm/ccwdev.h
> +++ b/arch/s390/include/asm/ccwdev.h
> @@ -18,6 +18,9 @@ struct irb;
> struct ccw1;
> struct ccw_dev_id;
>
> +/* from asm/schid.h */
> +struct subchannel_id;
> +
> /* simplified initializers for struct ccw_device:
> * CCW_DEVICE and CCW_DEVICE_DEVTYPE initialize one
> * entry in your MODULE_DEVICE_TABLE and set the match_flag correctly */
> @@ -226,5 +229,7 @@ int ccw_device_siosl(struct ccw_device *);
> // FIXME: these have to go
> extern int _ccw_device_get_subchannel_number(struct ccw_device *);
>
> +extern void ccw_device_get_schid(struct ccw_device *, struct subchannel_id *);
> +
> extern void *ccw_device_get_chp_desc(struct ccw_device *, int);
> #endif /* _S390_CCWDEV_H_ */
> diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
> index ec7fb6d..2ad832f 100644
> --- a/drivers/s390/cio/device_ops.c
> +++ b/drivers/s390/cio/device_ops.c
> @@ -763,6 +763,18 @@ _ccw_device_get_subchannel_number(struct ccw_device *cdev)
> return cdev->private->schid.sch_no;
> }
>
> +/**
> + * ccw_device_get_schid - obtain a subchannel id
> + * @cdev: device to obtain the id for
> + * @schid: where to fill in the values
> + */
> +void ccw_device_get_schid(struct ccw_device *cdev, struct subchannel_id *schid)

If you make this

u32 ccw_device_get_schid(struct ccw_device *cdev)

and you return the u32 (architected) value of the schid, not the internal struct, then you can save yourself the struct export (patch 2/5) and the ugly cast in patch 4/5 to get the u32 value.

Alex

> +{
> + struct subchannel *sch = to_subchannel(cdev->dev.parent);
> +
> + *schid = sch->schid;
> +}
> +EXPORT_SYMBOL_GPL(ccw_device_get_schid);
>
> MODULE_LICENSE("GPL");
> EXPORT_SYMBOL(ccw_device_set_options_mask);
> --
> 1.7.12.4
>