Re: [dpdk-dev] [PATCH v2 1/6] ethdev: fix port data mismatched in multiple process model

[Thomas Monjalon <thomas.monjalon@6wind.com>]

+Cc Sergio (maintainer of the secondary process thing)

2016-12-28 19:02, Yuanhan Liu:
> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -201,9 +201,6 @@ rte_eth_dev_allocate(const char *name)
>  		return NULL;
>  	}
>  
> -	if (rte_eth_dev_data == NULL)
> -		rte_eth_dev_data_alloc();
> -

It is dangerous to move this to rte_eth_dev_pci_probe.
Please keep it here and duplicate it in eth_dev_attach.

[...]
> +/*
> + * Attach to a port already registered by the primary process, which
> + * makes sure that the same device would both have the same port id
> + * in the primary and secondary process.
> + */
> +static struct rte_eth_dev *
> +eth_dev_attach(const char *name)

Maybe that the word "secondary" could help to differentiate of
the function rte_eth_dev_attach().

> +{
> +	uint8_t i;
> +	struct rte_eth_dev *eth_dev;
> +
> +	for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
> +		if (strcmp(rte_eth_dev_data[i].name, name) == 0)
> +			break;
> +	}
> +	if (i == RTE_MAX_ETHPORTS) {
> +		RTE_PMD_DEBUG_TRACE(
> +			"device %s is not driven by the primary process\n",
> +			name);
> +		return NULL;
> +	}
> +
> +	RTE_ASSERT(eth_dev->data->port_id == i);
> +
> +	eth_dev = &rte_eth_devices[i];
> +	eth_dev->data = &rte_eth_dev_data[i];
> +	eth_dev->attached = DEV_ATTACHED;
> +	nb_ports++;

I am a bit nervous when I see these lines duplicated from rte_eth_dev_allocate.
Not sure whether it deserves a common function or not.

[...]
> @@ -246,9 +275,26 @@ rte_eth_dev_pci_probe(struct rte_pci_driver *pci_drv,
> -	eth_dev = rte_eth_dev_allocate(ethdev_name);
> -	if (eth_dev == NULL)
> -		return -ENOMEM;
> +	if (rte_eth_dev_data == NULL)
> +		rte_eth_dev_data_alloc();
> +
> +	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> +		eth_dev = rte_eth_dev_allocate(ethdev_name);
> +		if (eth_dev == NULL)
> +			return -ENOMEM;
> +	} else {
> +		/*
> +		 * if we failed to attach a device, it means that
> +		 * device is skipped, due to some errors. Take
> +		 * virtio-net device as example, it could be the
> +		 * device is managed by virtio-net kernel driver.
> +		 * For such case, we return a positive value, to
> +		 * let EAL skip it as well.
> +		 */

This comment (a bit too long) should be placed between "if" and "return".

> +		eth_dev = eth_dev_attach(ethdev_name);
> +		if (eth_dev == NULL)
> +			return 1;
> +	}