On 03/04/2014 07:54 AM, Haiyang Zhang wrote:
> It moves the state setting for query into rndis_filter_receive_response().
> All callbacks including query-complete and status-callback are synchronized
> by channel->inbound_lock. This prevents pentential race between them.
This still looks racy to me. The problem is workqueue is not
synchronized with those here.
Consider the following case in netvsc_link_change():
if (rdev->link_state) {
... receive interrupt ...
rndis_filter_receice_response() which changes rdev->link_state
...
netif_carrier_off()
}
And also it need to schedule a work otherwise the link status is out of
sync.
> Signed-off-by: Haiyang Zhang <haiya...@microsoft.com>
> ---
> drivers/net/hyperv/rndis_filter.c | 21 ++++++++++++++++++++-
> 1 files changed, 20 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/hyperv/rndis_filter.c
> b/drivers/net/hyperv/rndis_filter.c
> index f0cc8ef..6a9f602 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -240,6 +240,22 @@ static int rndis_filter_send_request(struct rndis_device
> *dev,
> return ret;
> }
>
> +static void rndis_set_link_state(struct rndis_device *rdev,
> + struct rndis_request *request)
> +{
> + u32 link_status;
> + struct rndis_query_complete *query_complete;
> +
> + query_complete = &request->response_msg.msg.query_complete;
> +
> + if (query_complete->status == RNDIS_STATUS_SUCCESS &&
> + query_complete->info_buflen == sizeof(u32)) {
> + memcpy(&link_status, (void *)((unsigned long)query_complete +
> + query_complete->info_buf_offset), sizeof(u32));
> + rdev->link_state = link_status != 0;
> + }
> +}
> +
> static void rndis_filter_receive_response(struct rndis_device *dev,
> struct rndis_message *resp)
> {
> @@ -269,6 +285,10 @@ static void rndis_filter_receive_response(struct
> rndis_device *dev,
> sizeof(struct rndis_message) + RNDIS_EXT_LEN) {
> memcpy(&request->response_msg, resp,
> resp->msg_len);
> + if (request->request_msg.ndis_msg_type ==
> + RNDIS_MSG_QUERY && request->request_msg.msg.
> + query_req.oid == RNDIS_OID_GEN_MEDIA_CONNECT_STATUS)
> + rndis_set_link_state(dev, request);
> } else {
> netdev_err(ndev,
> "rndis response buffer overflow "
> @@ -617,7 +637,6 @@ static int rndis_filter_query_device_link_status(struct
> rndis_device *dev)
> ret = rndis_filter_query_device(dev,
> RNDIS_OID_GEN_MEDIA_CONNECT_STATUS,
> &link_status, &size);
> - dev->link_state = (link_status != 0) ? true : false;
>
> return ret;
> }
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