Re: [PATCH v2 3/7] vhost: refactor virtio_dev_merge_rx

On 3/7/2016 2:49 PM, Yuanhan Liu wrote:

On Mon, Mar 07, 2016 at 06:38:42AM +0000, Xie, Huawei wrote:

quoted

On 3/7/2016 2:35 PM, Yuanhan Liu wrote:

quoted

On Mon, Mar 07, 2016 at 06:22:25AM +0000, Xie, Huawei wrote:

quoted

On 2/18/2016 9:48 PM, Yuanhan Liu wrote:

quoted

+	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.

	--yliu