[dpdk-dev] [PATCH v2] kni: rework rte_kni_update_link using ioctl

[Igor Ryzhov]

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.

Signed-off-by: Igor Ryzhov <iryzhov at nfware.com>
---
v2: fix checkpatch warnings

 kernel/linux/kni/compat.h                     |  4 --
 kernel/linux/kni/kni_misc.c                   | 42 +++++++++++++++++++
 kernel/linux/kni/kni_net.c                    | 15 -------
 .../linux/eal/include/rte_kni_common.h        |  6 +++
 lib/librte_kni/rte_kni.c                      | 28 +++----------
 lib/librte_kni/rte_kni.h                      |  3 +-
 6 files changed, 55 insertions(+), 43 deletions(-)

diff --git a/kernel/linux/kni/compat.h b/kernel/linux/kni/compat.h
index fe0ee55e7..e0a491bcd 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_misc.c b/kernel/linux/kni/kni_misc.c
index aeb275329..9bcba68c8 100644
--- a/kernel/linux/kni/kni_misc.c
+++ b/kernel/linux/kni/kni_misc.c
@@ -462,6 +462,45 @@ 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.linkup)
+			netif_carrier_on(netdev);
+		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)
 {
@@ -483,6 +522,9 @@ 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 7bd3a9f1e..cd852eea3 100644
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -706,18 +706,6 @@ 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,
@@ -736,9 +724,6 @@ 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
 };
 
 static void kni_get_drvinfo(struct net_device *dev,
diff --git a/lib/librte_eal/linux/eal/include/rte_kni_common.h b/lib/librte_eal/linux/eal/include/rte_kni_common.h
index 70992d835..07a10dd93 100644
--- a/lib/librte_eal/linux/eal/include/rte_kni_common.h
+++ b/lib/librte_eal/linux/eal/include/rte_kni_common.h
@@ -125,10 +125,16 @@ struct rte_kni_device_info {
 	uint8_t mac_addr[6];
 };
 
+struct rte_kni_link_info {
+	char name[RTE_KNI_NAMESIZE];
+	unsigned int linkup;
+};
+
 #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_ */
diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 521db27c4..bdea03d5c 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -738,36 +738,20 @@ rte_kni_update_link(struct rte_kni *kni, unsigned int linkup)
 	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.linkup = linkup;
 
-	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;
 }
 
 void
diff --git a/lib/librte_kni/rte_kni.h b/lib/librte_kni/rte_kni.h
index b22446fa7..7e1cce1e0 100644
--- a/lib/librte_kni/rte_kni.h
+++ b/lib/librte_kni/rte_kni.h
@@ -247,9 +247,8 @@ int rte_kni_unregister_handlers(struct rte_kni *kni);
  *  > 0 for linkup.
  *
  * @return
+ *  On success: 0
  *  On failure: -1
- *  Previous link state == linkdown: 0
- *  Previous link state == linkup: 1
  */
 __rte_experimental
 int
-- 
2.23.0