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Subject: Re: [PATCH 1/4] vfio: ccw: fix cleanup if cp_prefetch fails
To:     Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>,
        Cornelia Huck <cohuck@redhat.com>
Cc:     Pierre Morel <pmorel@linux.vnet.ibm.com>,
        linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
        kvm@vger.kernel.org, borntraeger@de.ibm.com
References: <20180321020822.86255-1-bjsdjshi@linux.vnet.ibm.com>
 <20180321020822.86255-2-bjsdjshi@linux.vnet.ibm.com>
 <682d8b1c-5aca-7015-043b-a3f1446bf378@linux.vnet.ibm.com>
 <20180322022248.GB12194@bjsdjshi@linux.vnet.ibm.com>
 <54fd02cd-bd0b-889b-c40f-f9a32aa25d77@linux.vnet.ibm.com>
 <20180326142839.23bfc4f6.cohuck@redhat.com>
 <20180327014200.GH12194@bjsdjshi@linux.vnet.ibm.com>
From:   Halil Pasic <pasic@linux.vnet.ibm.com>
Date:   Fri, 20 Apr 2018 12:54:26 +0200
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ping

I think get this fixed. Better sooner than later.

On 03/27/2018 03:42 AM, Dong Jia Shi wrote:
> * Cornelia Huck <cohuck@redhat.com> [2018-03-26 14:28:39 +0200]:
> 
> [...]
> 
>>> By the way, since you will propose a new version,
>>> you have a long description of the cp_prefetch function in the code.
>>> I think you should modify it according to the changes and describe how and
>>> why the ch_len field of each chain is used and changed by this function.
>>>
>>> Something like:
>>>
>>> "
>>> For each chain composing the channel program:
>>> On entry ch_len hold the count of CCW to be translated.
>>
>> s/hold/holds/ ?
>>
> Sure.
> 
>>> On exit ch_len is adjusted to the count of successfully translated CCW.
>>>
>>> This allows cp_free to find in ch_len the count of CCW to free in a chain.
>>> "
>>>
>>> Could also be inside the commit message.
>>>
>>> Pierre
>>>
>>>
>>>>   
>>>>>> Acked-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
>>>>>> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
>>>>>> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
>>>>>> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
>>>>>> ---
>>>>>>    drivers/s390/cio/vfio_ccw_cp.c | 9 ++++++++-
>>>>>>    1 file changed, 8 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
>>>>>> index d9a2fffd034b..2be114db02f9 100644
>>>>>> --- a/drivers/s390/cio/vfio_ccw_cp.c
>>>>>> +++ b/drivers/s390/cio/vfio_ccw_cp.c
>>>>>> @@ -749,11 +749,18 @@ int cp_prefetch(struct channel_program *cp)
>>>>>>    		for (idx = 0; idx < len; idx++) {
>>>>>>    			ret = ccwchain_fetch_one(chain, idx, cp);
>>>>>>    			if (ret)
>>>>>> -				return ret;
>>>>>> +				goto out_err;
>>>>>>    		}
>>>>>>    	}
>>>>>>
>>>>>>    	return 0;
>>>>>> +out_err:
>>>>>> +	/* Only cleanup the chain elements that where actually translated. */
>>
>> s/where/were/
> Ok.
> 
>>
>>>>>> +	chain->ch_len = idx;
>>>>>> +	list_for_each_entry_continue(chain, &cp->ccwchain_list, next) {
>>>>>> +		chain->ch_len = 0;
>>>>>> +	}
>>>>>> +	return ret;
>>>>>>    }
>>>>>>
>>>>>>    /**
>>>>>>   
>>>
>>
>