Re: [dpdk-dev] [PATCH v4 1/2] kni: rework rte_kni_update_link using ioctl

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 7/4/2021 6:06 PM, Igor Ryzhov wrote:
> Current implementation doesn't allow us to update KNI carrier if the
> interface is not yet UP in kernel. It means that we can't use it in the
> same thread which is processing rte_kni_ops.config_network_if, which is
> very convenient, because it allows us to have correct carrier status
> of the interface right after we enabled it and we don't have to use any
> additional thread to track link status.
> 
> Propagating speed/duplex/autoneg to the kernel module also allows us to
> implement ethtool_ops.get_link_ksettings callback.
> 
> Suggested-by: Dan Gora <dg@adax.com>
> Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
> ---
>  app/test/test_kni.c         | 32 ++++++++++---------------
>  examples/kni/main.c         |  2 +-
>  kernel/linux/kni/compat.h   |  4 ----
>  kernel/linux/kni/kni_dev.h  |  5 ++++
>  kernel/linux/kni/kni_misc.c | 47 +++++++++++++++++++++++++++++++++++++
>  kernel/linux/kni/kni_net.c  | 15 ------------
>  lib/kni/rte_kni.c           | 38 ++++++++----------------------
>  lib/kni/rte_kni.h           | 10 ++++----
>  lib/kni/rte_kni_common.h    |  9 +++++++
>  9 files changed, 89 insertions(+), 73 deletions(-)
> 
> diff --git a/app/test/test_kni.c b/app/test/test_kni.c
> index 96733554b6c4..f9300552b3f6 100644
> --- a/app/test/test_kni.c
> +++ b/app/test/test_kni.c
> @@ -125,6 +125,7 @@ kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
>  static int
>  test_kni_link_change(void)
>  {
> +	struct rte_eth_link link;
>  	int ret;
>  	int pid;
>  
> @@ -135,42 +136,35 @@ test_kni_link_change(void)
>  	}
>  
>  	if (pid == 0) {
> +		link.link_speed = ETH_SPEED_NUM_10G;
> +		link.link_duplex = ETH_LINK_FULL_DUPLEX;
> +		link.link_autoneg = ETH_LINK_AUTONEG;
> +
>  		printf("Starting KNI Link status change tests.\n");
>  		if (system(IFCONFIG TEST_KNI_PORT" up") == -1) {
>  			ret = -1;
>  			goto error;
>  		}
>  
> -		ret = rte_kni_update_link(test_kni_ctx, 1);
> +		link.link_status = ETH_LINK_UP;
> +		ret = rte_kni_update_link(test_kni_ctx, &link);
>  		if (ret < 0) {
>  			printf("Failed to change link state to Up ret=%d.\n",
>  				ret);
>  			goto error;
>  		}
>  		rte_delay_ms(1000);
> -		printf("KNI: Set LINKUP, previous state=%d\n", ret);
> -
> -		ret = rte_kni_update_link(test_kni_ctx, 0);
> -		if (ret != 1) {
> -			printf(
> -		"Failed! Previous link state should be 1, returned %d.\n",
> -				ret);
> -			goto error;
> -		}
> -		rte_delay_ms(1000);
> -		printf("KNI: Set LINKDOWN, previous state=%d\n", ret);
> +		printf("KNI: Set LINKUP\n");
>  
> -		ret = rte_kni_update_link(test_kni_ctx, 1);
> -		if (ret != 0) {
> -			printf(
> -		"Failed! Previous link state should be 0, returned %d.\n",
> +		link.link_status = ETH_LINK_DOWN;
> +		ret = rte_kni_update_link(test_kni_ctx, &link);
> +		if (ret < 0) {
> +			printf("Failed to change link state to Down ret=%d.\n",
>  				ret);
>  			goto error;
>  		}

Is there a way to verify the link status of the KNI interface, to double check
setting link status succedded?

> -		printf("KNI: Set LINKUP, previous state=%d\n", ret);
> -
> -		ret = 0;
>  		rte_delay_ms(1000);
> +		printf("KNI: Set LINKDOWN\n");
>  
>  error:
>  		if (system(IFCONFIG TEST_KNI_PORT" down") == -1)
> diff --git a/examples/kni/main.c b/examples/kni/main.c
> index beabb3c848aa..5833037cf1c9 100644
> --- a/examples/kni/main.c
> +++ b/examples/kni/main.c
> @@ -755,7 +755,7 @@ monitor_all_ports_link_status(void *arg)
>  			}
>  			for (i = 0; i < p[portid]->nb_kni; i++) {
>  				prev = rte_kni_update_link(p[portid]->kni[i],
> -						link.link_status);
> +						&link);
>  				log_link_state(p[portid]->kni[i], prev, &link);
>  			}
>  		}
> diff --git a/kernel/linux/kni/compat.h b/kernel/linux/kni/compat.h
> index 5f65640d5ed2..995d109c275a 100644
> --- a/kernel/linux/kni/compat.h
> +++ b/kernel/linux/kni/compat.h
> @@ -61,10 +61,6 @@
>  #define kni_sock_map_fd(s) sock_map_fd(s, 0)
>  #endif
>  
> -#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 9, 0)
> -#define HAVE_CHANGE_CARRIER_CB
> -#endif
> -
>  #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 14, 0)
>  #define ether_addr_copy(dst, src) memcpy(dst, src, ETH_ALEN)
>  #endif
> diff --git a/kernel/linux/kni/kni_dev.h b/kernel/linux/kni/kni_dev.h
> index c15da311ba25..969108cc30f8 100644
> --- a/kernel/linux/kni/kni_dev.h
> +++ b/kernel/linux/kni/kni_dev.h
> @@ -88,6 +88,11 @@ struct kni_dev {
>  	void *alloc_va[MBUF_BURST_SZ];
>  
>  	struct task_struct *usr_tsk;
> +
> +	/* correct when netif_carrier_ok */
> +	uint32_t speed;
> +	uint8_t duplex;
> +	uint8_t autoneg;
>  };
>  
>  #ifdef HAVE_IOVA_TO_KVA_MAPPING_SUPPORT
> diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
> index 2b464c438113..30ee69661935 100644
> --- a/kernel/linux/kni/kni_misc.c
> +++ b/kernel/linux/kni/kni_misc.c
> @@ -481,6 +481,50 @@ kni_ioctl_release(struct net *net, uint32_t ioctl_num,
>  	return ret;
>  }
>  
> +static int
> +kni_ioctl_link(struct net *net, uint32_t ioctl_num,
> +		unsigned long ioctl_param)
> +{
> +	struct kni_net *knet = net_generic(net, kni_net_id);
> +	int ret = -EINVAL;
> +	struct kni_dev *dev, *n;
> +	struct rte_kni_link_info link_info;
> +	struct net_device *netdev;
> +
> +	if (_IOC_SIZE(ioctl_num) > sizeof(link_info))
> +		return -EINVAL;
> +
> +	if (copy_from_user(&link_info, (void *)ioctl_param, sizeof(link_info)))
> +		return -EFAULT;
> +
> +	if (strlen(link_info.name) == 0)
> +		return -EINVAL;
> +
> +	down_read(&knet->kni_list_lock);
> +	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
> +		if (strncmp(dev->name, link_info.name, RTE_KNI_NAMESIZE) != 0)
> +			continue;
> +
> +		netdev = dev->net_dev;
> +
> +		if (link_info.status) {
> +			netif_carrier_on(netdev);
> +
> +			dev->speed = link_info.speed;
> +			dev->duplex = link_info.duplex;
> +			dev->autoneg = link_info.autoneg;
> +		} else {
> +			netif_carrier_off(netdev);
> +		}
> +
> +		ret = 0;
> +		break;
> +	}
> +	up_read(&knet->kni_list_lock);
> +
> +	return ret;
> +}
> +
>  static int
>  kni_ioctl(struct inode *inode, uint32_t ioctl_num, unsigned long ioctl_param)
>  {
> @@ -502,6 +546,9 @@ kni_ioctl(struct inode *inode, uint32_t ioctl_num, unsigned long ioctl_param)
>  	case _IOC_NR(RTE_KNI_IOCTL_RELEASE):
>  		ret = kni_ioctl_release(net, ioctl_num, ioctl_param);
>  		break;
> +	case _IOC_NR(RTE_KNI_IOCTL_LINK):
> +		ret = kni_ioctl_link(net, ioctl_num, ioctl_param);
> +		break;
>  	default:
>  		pr_debug("IOCTL default\n");
>  		break;
> diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
> index 611719b5ee27..99da8d37dd6b 100644
> --- a/kernel/linux/kni/kni_net.c
> +++ b/kernel/linux/kni/kni_net.c
> @@ -778,18 +778,6 @@ kni_net_set_mac(struct net_device *netdev, void *p)
>  	return (ret == 0 ? req.result : ret);
>  }
>  
> -#ifdef HAVE_CHANGE_CARRIER_CB
> -static int
> -kni_net_change_carrier(struct net_device *dev, bool new_carrier)
> -{
> -	if (new_carrier)
> -		netif_carrier_on(dev);
> -	else
> -		netif_carrier_off(dev);
> -	return 0;
> -}
> -#endif
> -
>  static const struct header_ops kni_net_header_ops = {
>  	.create  = kni_net_header,
>  	.parse   = eth_header_parse,
> @@ -808,9 +796,6 @@ static const struct net_device_ops kni_net_netdev_ops = {
>  	.ndo_change_mtu = kni_net_change_mtu,
>  	.ndo_tx_timeout = kni_net_tx_timeout,
>  	.ndo_set_mac_address = kni_net_set_mac,
> -#ifdef HAVE_CHANGE_CARRIER_CB
> -	.ndo_change_carrier = kni_net_change_carrier,
> -#endif

What do you think keeping the 'carrier' interface? Even the API not using it, it
can be useful, what do you think?

>  };
>  
>  static void kni_get_drvinfo(struct net_device *dev,
> diff --git a/lib/kni/rte_kni.c b/lib/kni/rte_kni.c
> index eb24b0d0ae4e..0a7b562abf11 100644
> --- a/lib/kni/rte_kni.c
> +++ b/lib/kni/rte_kni.c
> @@ -784,43 +784,25 @@ rte_kni_unregister_handlers(struct rte_kni *kni)
>  }
>  
>  int
> -rte_kni_update_link(struct rte_kni *kni, unsigned int linkup)
> +rte_kni_update_link(struct rte_kni *kni, struct rte_eth_link *link)
>  {
> -	char path[64];
> -	char old_carrier[2];
> -	const char *new_carrier;
> -	int old_linkup;
> -	int fd, ret;
> +	struct rte_kni_link_info link_info;
>  
>  	if (kni == NULL)
>  		return -1;
>  
> -	snprintf(path, sizeof(path), "/sys/devices/virtual/net/%s/carrier",
> -		kni->name);
> +	snprintf(link_info.name, RTE_KNI_NAMESIZE, "%s", kni->name);
> +	link_info.speed = link->link_speed;
> +	link_info.duplex = link->link_duplex;
> +	link_info.autoneg = link->link_autoneg;
> +	link_info.status = link->link_status;
>  
> -	fd = open(path, O_RDWR);
> -	if (fd == -1) {
> -		RTE_LOG(ERR, KNI, "Failed to open file: %s.\n", path);
> +	if (ioctl(kni_fd, RTE_KNI_IOCTL_LINK, &link_info) < 0) {
> +		RTE_LOG(ERR, KNI, "Fail to update KNI link\n");
>  		return -1;
>  	}
>  
> -	ret = read(fd, old_carrier, 2);
> -	if (ret < 1) {
> -		close(fd);
> -		return -1;
> -	}
> -	old_linkup = (old_carrier[0] == '1');
> -
> -	new_carrier = linkup ? "1" : "0";
> -	ret = write(fd, new_carrier, 1);
> -	if (ret < 1) {
> -		RTE_LOG(ERR, KNI, "Failed to write file: %s.\n", path);
> -		close(fd);
> -		return -1;
> -	}
> -
> -	close(fd);
> -	return old_linkup;
> +	return 0;
>  }

Can you please add new API to KNI PMD too? To set the link up when port started.

>  
>  void
> diff --git a/lib/kni/rte_kni.h b/lib/kni/rte_kni.h
> index b0eaf4610416..ab5990fd210d 100644
> --- a/lib/kni/rte_kni.h
> +++ b/lib/kni/rte_kni.h
> @@ -21,6 +21,7 @@
>  #include <rte_memory.h>
>  #include <rte_mempool.h>
>  #include <rte_ether.h>
> +#include <rte_ethdev.h>
>  
>  #include <rte_kni_common.h>
>  
> @@ -245,18 +246,15 @@ int rte_kni_unregister_handlers(struct rte_kni *kni);
>   * @param kni
>   *  pointer to struct rte_kni.
>   * @param linkup
> - *  New link state:
> - *  0 for linkdown.
> - *  > 0 for linkup.
> + *  new link state, speed, duplex, autoneg.
>   *
>   * @return
> + *  On success: 0
>   *  On failure: -1
> - *  Previous link state == linkdown: 0
> - *  Previous link state == linkup: 1
>   */

This was useful to detect the change in the status and log according.
With current change KNI example will keep logging the link state.

Also in the KNI sample it periodically reads the link status from the device and
applies it to the kni device, with current implementation it will keep updating
the link status. Can we add a logic in the KNI sample so that update the KNI
interface only if physical device link status changed?

>  __rte_experimental
>  int
> -rte_kni_update_link(struct rte_kni *kni, unsigned int linkup);
> +rte_kni_update_link(struct rte_kni *kni, struct rte_eth_link *link);
>  
>  /**
>   *  Close KNI device.
> diff --git a/lib/kni/rte_kni_common.h b/lib/kni/rte_kni_common.h
> index b547ea550171..35a1620e0bd2 100644
> --- a/lib/kni/rte_kni_common.h
> +++ b/lib/kni/rte_kni_common.h
> @@ -130,10 +130,19 @@ struct rte_kni_device_info {
>  	uint8_t iova_mode;
>  };
>  
> +struct rte_kni_link_info {
> +	char name[RTE_KNI_NAMESIZE];
> +	unsigned int speed;
> +	unsigned char duplex;
> +	unsigned char autoneg;
> +	unsigned char status;
> +};

Should we prefer fixed size storage types "uint32_t speed" or "unsigned int",
did you select current ones explicitly?

> +
>  #define KNI_DEVICE "kni"
>  
>  #define RTE_KNI_IOCTL_TEST    _IOWR(0, 1, int)
>  #define RTE_KNI_IOCTL_CREATE  _IOWR(0, 2, struct rte_kni_device_info)
>  #define RTE_KNI_IOCTL_RELEASE _IOWR(0, 3, struct rte_kni_device_info)
> +#define RTE_KNI_IOCTL_LINK    _IOWR(0, 4, struct rte_kni_link_info)
>  
>  #endif /* _RTE_KNI_COMMON_H_ */
>