Re: [dpdk-dev] [PATCH v3 3/5] bus/vdev: bus scan by multi-process channel

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 19-Apr-18 5:50 PM, Jianfeng Tan wrote:
> To scan the vdevs in primary, we send request to primary process
> to obtain the names for vdevs.
> 
> Only the name is shared from the primary. In probe(), the device
> driver is supposed to locate (or request more) the detail
> information from the primary.
> 
> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
> Reviewed-by: Qi Zhang <qi.z.zhang@intel.com>
> ---

<...>

> +static int
> +vdev_action(const struct rte_mp_msg *mp_msg, const void *peer)
> +{
> +	struct rte_vdev_device *dev;
> +	struct rte_mp_msg mp_resp;
> +	struct vdev_param *ou = (struct vdev_param *)&mp_resp.param;
> +	const struct vdev_param *in = (const struct vdev_param *)mp_msg->param;
> +	const char *devname;
> +	int num;
> +
> +	strcpy(mp_resp.name, "vdev");
> +	mp_resp.len_param = sizeof(*ou);
> +	mp_resp.num_fds = 0;
> +
> +	switch (in->type) {
> +	case VDEV_SCAN_REQ:
> +		ou->type = VDEV_SCAN_ONE;
> +		ou->num = 1;
> +		num = 0;
> +
> +		rte_spinlock_lock(&vdev_device_list_lock);
> +		TAILQ_FOREACH(dev, &vdev_device_list, next) {
> +			devname = rte_vdev_device_name(dev);
> +			if (strlen(devname) == 0)
> +				VDEV_LOG(INFO, "vdev with no name is not sent");
> +			VDEV_LOG(INFO, "send vdev, %s", devname);
> +			strncpy(ou->name, devname, RTE_DEV_NAME_MAX_LEN);

Probably better use strlcpy as it always null-terminates.

> +			if (rte_mp_sendmsg(&mp_resp) < 0)
> +				VDEV_LOG(ERR, "send vdev, %s, failed, %s",
> +					 devname, strerror(rte_errno));
> +			num++;

Some comments on what is going on here (why are we sending messages in 
response? why multiple? who will receive these messages?) would be nice. 
I have a sneaking suspicion that you could've packed the response into 
one single message, but i'm not completely sure what is going on here, 
so maybe what you have here makes sense...

> +		}
> +		rte_spinlock_unlock(&vdev_device_list_lock);
> +
> +		ou->type = VDEV_SCAN_REP;
> +		ou->num = num;
> +		if (rte_mp_reply(&mp_resp, peer) < 0)
> +			VDEV_LOG(ERR, "Failed to reply a scan request");
> +		break;

<...>

-- 
Thanks,
Anatoly