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? --yliu