[dpdk-dev] [PATCH v2 3/7] vhost: refactor virtio_dev_merge_rx

Xie, Huawei huawei.xie at intel.com
Mon Mar 7 08:16:39 CET 2016


On 3/7/2016 3:04 PM, Xie, Huawei wrote:
> On 3/7/2016 2:49 PM, Yuanhan Liu wrote:
>> On Mon, Mar 07, 2016 at 06:38:42AM +0000, Xie, Huawei wrote:
>>> On 3/7/2016 2:35 PM, Yuanhan Liu wrote:
>>>> On Mon, Mar 07, 2016 at 06:22:25AM +0000, Xie, Huawei wrote:
>>>>> On 2/18/2016 9:48 PM, Yuanhan Liu wrote:
>>>>>> +	uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
>>>>>> +	uint32_t vec_id = *vec_idx;
>>>>>> +	uint32_t len    = *allocated;
>>>>>>  
>>>>> There is bug not using volatile to retrieve the avail idx.
>>>> avail_idx? This is actually from "vq->last_used_idx_res". 
>>> uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)]
>>>
>>> the idx retrieved from avail->ring. 
>> Hmm.. I saw quite many similar lines of code retrieving an index from
>> avail->ring, but none of them acutally use "volatile". So, a bug?
> Others are not. This function is inline, and is in one translation unit
> with its caller.

Oh, my fault. For the avail idx, we should take care on whether using
volatile.

>> 	--yliu
>>
>



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