Re: [RFC v1 1/4] vfio-ccw: Set orb.cmd.c64 before calling ccwchain_handle_ccw

Farhan Ali
2019-07-02T13:56:27Z

On 07/02/2019 04:26 AM, Cornelia Huck wrote:
> On Mon, 1 Jul 2019 12:23:43 -0400
> Farhan Ali <alifm@linux.ibm.com> wrote:
>
>> Because ccwchain_handle_ccw calls ccwchain_calc_length and
>> as per the comment we should set orb.cmd.c64 before calling
>> ccwchanin_calc_length.
>>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>> drivers/s390/cio/vfio_ccw_cp.c | 10 +++++-----
>> 1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
>> index d6a8dff..5ac4c1e 100644
>> --- a/drivers/s390/cio/vfio_ccw_cp.c
>> +++ b/drivers/s390/cio/vfio_ccw_cp.c
>> @@ -640,16 +640,16 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
>> memcpy(&cp->orb, orb, sizeof(*orb));
>> cp->mdev = mdev;
>>
>> - /* Build a ccwchain for the first CCW segment */
>> - ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
>> - if (ret)
>> - cp_free(cp);
>> -
>> /* It is safe to force: if not set but idals used
>> * ccwchain_calc_length returns an error.
>> */
>> cp->orb.cmd.c64 = 1;
>>
>> + /* Build a ccwchain for the first CCW segment */
>> + ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
>> + if (ret)
>> + cp_free(cp);
>> +
>> if (!ret)
>> cp->initialized = true;
>>
>
> Hm... has this ever been correct, or did this break only with the
> recent refactorings?
>
> (IOW, what should Fixes: point to?)
>
>

I think it was correct before some of the new refactoring we did. But we
do need to set before calling ccwchain_calc_length, because the function
does have a check for orb.cmd.64. I will see which exact commit did it.

Thanks
Farhan