Re: [dpdk-dev] [PATCH v4 01/19] vhost: fix messages error checks

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 10/09/2018 02:54 PM, Tiwei Bie wrote:
> On Tue, Oct 09, 2018 at 02:20:47PM +0200, Maxime Coquelin wrote:
>> On 10/09/2018 10:03 AM, Tiwei Bie wrote:
>>> On Mon, Oct 08, 2018 at 05:25:39PM +0200, Maxime Coquelin wrote:
>>>> Return of message handling has now changed to an enum that can
>>>> take non-negative value that is not zero in case a reply is
>>>> needed. But the code checking the variable afterwards has not
>>>> been updated, leading to success messages handling being
>>>> treated as errors.
>>>>
>>>> Fixes: 2f270595c05d ("vhost: rework message handling as a callback array")
>>>
>>> Fixline should be:
>>> Fixes: 0bff510b5ea6 ("vhost: unify message handling function signature")
>>>
>>>>
>>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>>> Acked-by: Ilya Maximets <i.maximets@samsung.com>
>>>> ---
>>>>    lib/librte_vhost/vhost_user.c | 6 +++---
>>>>    1 file changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>>>> index 7ef3fb4a4..060b41893 100644
>>>> --- a/lib/librte_vhost/vhost_user.c
>>>> +++ b/lib/librte_vhost/vhost_user.c
>>>> @@ -1783,7 +1783,7 @@ vhost_user_msg_handler(int vid, int fd)
>>>>    	}
>>>>    skip_to_post_handle:
>>>> -	if (!ret && dev->extern_ops.post_msg_handle) {
>>>> +	if (ret != VH_RESULT_ERR && dev->extern_ops.post_msg_handle) {
>>>>    		uint32_t need_reply;
>>>>    		ret = (*dev->extern_ops.post_msg_handle)(
>>>> @@ -1800,10 +1800,10 @@ vhost_user_msg_handler(int vid, int fd)
>>>>    		vhost_user_unlock_all_queue_pairs(dev);
>>>>    	if (msg.flags & VHOST_USER_NEED_REPLY) {
>>>> -		msg.payload.u64 = !!ret;
>>>> +		msg.payload.u64 = ret == VH_RESULT_ERR;
>>>>    		msg.size = sizeof(msg.payload.u64);
>>>>    		send_vhost_reply(fd, &msg);
>>>> -	} else if (ret) {
>>>> +	} else if (ret == VH_RESULT_ERR) {
>>>>    		RTE_LOG(ERR, VHOST_CONFIG,
>>>>    			"vhost message handling failed.\n");
>>>>    		return -1;
>>>
>>> We also need to take care of the return value of .pre_msg_handle()
>>> and .post_msg_handle(). Otherwise, errors could be ignored.
>>
>> Right. What I plan to do is setting ret to VH_RESULT_ERR if
>> pre/post_msg_handler() return is negative.
>>
>> Does that sound reasonable to you?
>>
>> I see that vhost-crypto does not respect the callbacks documentation wrt
>> to return value, and we might want to change the callbacks documentation
>> so that it returns an enum vh_result.
> 
> I think it would be better to change the callbacks documentation
> to ask them to return enum vh_result as well.

Yes, that's what I meant.

So I'm adding to this patch the fix to the callback return type to enum
vh_result, and convert vhost_crypto to it.

Cheers,
Maxime
>>
>>>> -- 
>>>> 2.17.1
>>>>