[dpdk-dev] [PATCH v3] kni: allow per-net instances

[Dex Chen <dex.chen@ruckuswireless.com>]

There is a global variable 'device_in_use' which is used to make sure
only one instance is using /dev/kni device. If you were using LXC, you
will find there is only one instance of KNI example could be run even
different namespaces were created.

In order to have /dev/kni used simultaneously in different namespaces,
making all of global variables as per network namespace variables.

With regard to single kernel thread mode, there will be one kernel
thread for each of network namespace.

Signed-off-by: Dex Chen <dex.chen@ruckuswireless.com>
---
Changes in v3:
 - Move change logs in annotation

Changes in v2:
 - Remove kni_exit_net
 - Revise the order of register/unregister of pernet_subsys
 - Fix warnings of checkpatch
 - Fix issue of dereferencing to NULL pointer in kni_release()

 lib/librte_eal/linuxapp/kni/kni_misc.c | 136 +++++++++++++++++++++------------
 1 file changed, 87 insertions(+), 49 deletions(-)

diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c b/lib/librte_eal/linuxapp/kni/kni_misc.c
index 2e9fa89..635e18f 100644
--- a/lib/librte_eal/linuxapp/kni/kni_misc.c
+++ b/lib/librte_eal/linuxapp/kni/kni_misc.c
@@ -28,6 +28,9 @@
 #include <linux/pci.h>
 #include <linux/kthread.h>
 #include <linux/rwsem.h>
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
 
 #include <exec-env/rte_kni_common.h>
 #include "kni_dev.h"
@@ -90,18 +93,40 @@ static unsigned multiple_kthread_on = 0;
 
 #define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */
 
-static volatile unsigned long device_in_use; /* device in use flag */
-static struct task_struct *kni_kthread;
+static int kni_net_id;
 
-/* kni list lock */
-static DECLARE_RWSEM(kni_list_lock);
+struct kni_net {
+	unsigned long device_in_use; /* device in use flag */
+	struct task_struct *kni_kthread;
+	struct rw_semaphore kni_list_lock;
+	struct list_head kni_list_head;
+};
+
+static __net_init int kni_init_net(struct net *net)
+{
+	struct kni_net *knet = net_generic(net, kni_net_id);
 
-/* kni list */
-static struct list_head kni_list_head = LIST_HEAD_INIT(kni_list_head);
+	/* Clear the bit of device in use */
+	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
+
+	init_rwsem(&knet->kni_list_lock);
+	INIT_LIST_HEAD(&knet->kni_list_head);
+
+	return 0;
+}
+
+static struct pernet_operations kni_net_ops = {
+	.init = kni_init_net,
+	.exit = NULL,
+	.id   = &kni_net_id,
+	.size = sizeof(struct kni_net),
+};
 
 static int __init
 kni_init(void)
 {
+	int rc;
+
 	KNI_PRINT("######## DPDK kni module loading ########\n");
 
 	if (kni_parse_kthread_mode() < 0) {
@@ -109,13 +134,15 @@ kni_init(void)
 		return -EINVAL;
 	}
 
-	if (misc_register(&kni_misc) != 0) {
-		KNI_ERR("Misc registration failed\n");
+	rc = register_pernet_subsys(&kni_net_ops);
+	if (rc)
 		return -EPERM;
-	}
 
-	/* Clear the bit of device in use */
-	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &device_in_use);
+	rc = misc_register(&kni_misc);
+	if (rc != 0) {
+		KNI_ERR("Misc registration failed\n");
+		goto out;
+	}
 
 	/* Configure the lo mode according to the input parameter */
 	kni_net_config_lo_mode(lo_mode);
@@ -123,12 +150,17 @@ kni_init(void)
 	KNI_PRINT("######## DPDK kni module loaded  ########\n");
 
 	return 0;
+
+out:
+	unregister_pernet_subsys(&kni_net_ops);
+	return rc;
 }
 
 static void __exit
 kni_exit(void)
 {
 	misc_deregister(&kni_misc);
+	unregister_pernet_subsys(&kni_net_ops);
 	KNI_PRINT("####### DPDK kni module unloaded  #######\n");
 }
 
@@ -151,23 +183,27 @@ kni_parse_kthread_mode(void)
 static int
 kni_open(struct inode *inode, struct file *file)
 {
-	/* kni device can be opened by one user only, test and set bit */
-	if (test_and_set_bit(KNI_DEV_IN_USE_BIT_NUM, &device_in_use))
+	struct net *net = current->nsproxy->net_ns;
+	struct kni_net *knet = net_generic(net, kni_net_id);
+
+	/* kni device can be opened by one user only per netns */
+	if (test_and_set_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use))
 		return -EBUSY;
 
 	/* Create kernel thread for single mode */
 	if (multiple_kthread_on == 0) {
 		KNI_PRINT("Single kernel thread for all KNI devices\n");
 		/* Create kernel thread for RX */
-		kni_kthread = kthread_run(kni_thread_single, NULL,
+		knet->kni_kthread = kthread_run(kni_thread_single, (void *)knet,
 						"kni_single");
-		if (IS_ERR(kni_kthread)) {
+		if (IS_ERR(knet->kni_kthread)) {
 			KNI_ERR("Unable to create kernel threaed\n");
-			return PTR_ERR(kni_kthread);
+			return PTR_ERR(knet->kni_kthread);
 		}
 	} else
 		KNI_PRINT("Multiple kernel thread mode enabled\n");
 
+	file->private_data = get_net(net);
 	KNI_PRINT("/dev/kni opened\n");
 
 	return 0;
@@ -176,17 +212,19 @@ kni_open(struct inode *inode, struct file *file)
 static int
 kni_release(struct inode *inode, struct file *file)
 {
+	struct net *net = file->private_data;
+	struct kni_net *knet = net_generic(net, kni_net_id);
 	struct kni_dev *dev, *n;
 
 	/* Stop kernel thread for single mode */
 	if (multiple_kthread_on == 0) {
 		/* Stop kernel thread */
-		kthread_stop(kni_kthread);
-		kni_kthread = NULL;
+		kthread_stop(knet->kni_kthread);
+		knet->kni_kthread = NULL;
 	}
 
-	down_write(&kni_list_lock);
-	list_for_each_entry_safe(dev, n, &kni_list_head, list) {
+	down_write(&knet->kni_list_lock);
+	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 		/* Stop kernel thread for multiple mode */
 		if (multiple_kthread_on && dev->pthread != NULL) {
 			kthread_stop(dev->pthread);
@@ -199,26 +237,28 @@ kni_release(struct inode *inode, struct file *file)
 		kni_dev_remove(dev);
 		list_del(&dev->list);
 	}
-	up_write(&kni_list_lock);
+	up_write(&knet->kni_list_lock);
 
 	/* Clear the bit of device in use */
-	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &device_in_use);
+	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
 
+	put_net(net);
 	KNI_PRINT("/dev/kni closed\n");
 
 	return 0;
 }
 
 static int
-kni_thread_single(void *unused)
+kni_thread_single(void *data)
 {
+	struct kni_net *knet = data;
 	int j;
 	struct kni_dev *dev;
 
 	while (!kthread_should_stop()) {
-		down_read(&kni_list_lock);
+		down_read(&knet->kni_list_lock);
 		for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
-			list_for_each_entry(dev, &kni_list_head, list) {
+			list_for_each_entry(dev, &knet->kni_list_head, list) {
 #ifdef RTE_KNI_VHOST
 				kni_chk_vhost_rx(dev);
 #else
@@ -227,7 +267,7 @@ kni_thread_single(void *unused)
 				kni_net_poll_resp(dev);
 			}
 		}
-		up_read(&kni_list_lock);
+		up_read(&knet->kni_list_lock);
 #ifdef RTE_KNI_PREEMPT_DEFAULT
 		/* reschedule out for a while */
 		schedule_timeout_interruptible(usecs_to_jiffies( \
@@ -305,8 +345,10 @@ kni_check_param(struct kni_dev *kni, struct rte_kni_device_info *dev)
 }
 
 static int
-kni_ioctl_create(unsigned int ioctl_num, unsigned long ioctl_param)
+kni_ioctl_create(struct net *net,
+		unsigned int ioctl_num, unsigned long ioctl_param)
 {
+	struct kni_net *knet = net_generic(net, kni_net_id);
 	int ret;
 	struct rte_kni_device_info dev_info;
 	struct pci_dev *pci = NULL;
@@ -314,7 +356,6 @@ kni_ioctl_create(unsigned int ioctl_num, unsigned long ioctl_param)
 	struct net_device *net_dev = NULL;
 	struct net_device *lad_dev = NULL;
 	struct kni_dev *kni, *dev, *n;
-	struct net *net;
 
 	printk(KERN_INFO "KNI: Creating kni...\n");
 	/* Check the buffer size, to avoid warning */
@@ -339,14 +380,14 @@ kni_ioctl_create(unsigned int ioctl_num, unsigned long ioctl_param)
 	}
 
 	/* Check if it has been created */
-	down_read(&kni_list_lock);
-	list_for_each_entry_safe(dev, n, &kni_list_head, list) {
+	down_read(&knet->kni_list_lock);
+	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 		if (kni_check_param(dev, &dev_info) < 0) {
-			up_read(&kni_list_lock);
+			up_read(&knet->kni_list_lock);
 			return -EINVAL;
 		}
 	}
-	up_read(&kni_list_lock);
+	up_read(&knet->kni_list_lock);
 
 	net_dev = alloc_netdev(sizeof(struct kni_dev), dev_info.name,
 #ifdef NET_NAME_UNKNOWN
@@ -358,13 +399,7 @@ kni_ioctl_create(unsigned int ioctl_num, unsigned long ioctl_param)
 		return -EBUSY;
 	}
 
-	net = get_net_ns_by_pid(task_pid_vnr(current));
-	if (IS_ERR(net)) {
-		free_netdev(net_dev);
-		return PTR_ERR(net);
-	}
 	dev_net_set(net_dev, net);
-	put_net(net);
 
 	kni = netdev_priv(net_dev);
 
@@ -494,16 +529,18 @@ kni_ioctl_create(unsigned int ioctl_num, unsigned long ioctl_param)
 		wake_up_process(kni->pthread);
 	}
 
-	down_write(&kni_list_lock);
-	list_add(&kni->list, &kni_list_head);
-	up_write(&kni_list_lock);
+	down_write(&knet->kni_list_lock);
+	list_add(&kni->list, &knet->kni_list_head);
+	up_write(&knet->kni_list_lock);
 
 	return 0;
 }
 
 static int
-kni_ioctl_release(unsigned int ioctl_num, unsigned long ioctl_param)
+kni_ioctl_release(struct net *net,
+		unsigned int 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_device_info dev_info;
@@ -521,8 +558,8 @@ kni_ioctl_release(unsigned int ioctl_num, unsigned long ioctl_param)
 	if (strlen(dev_info.name) == 0)
 		return ret;
 
-	down_write(&kni_list_lock);
-	list_for_each_entry_safe(dev, n, &kni_list_head, list) {
+	down_write(&knet->kni_list_lock);
+	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 		if (strncmp(dev->name, dev_info.name, RTE_KNI_NAMESIZE) != 0)
 			continue;
 
@@ -539,7 +576,7 @@ kni_ioctl_release(unsigned int ioctl_num, unsigned long ioctl_param)
 		ret = 0;
 		break;
 	}
-	up_write(&kni_list_lock);
+	up_write(&knet->kni_list_lock);
 	printk(KERN_INFO "KNI: %s release kni named %s\n",
 		(ret == 0 ? "Successfully" : "Unsuccessfully"), dev_info.name);
 
@@ -552,8 +589,9 @@ kni_ioctl(struct inode *inode,
 	unsigned long ioctl_param)
 {
 	int ret = -EINVAL;
+	struct net *net = current->nsproxy->net_ns;
 
-	KNI_DBG("IOCTL num=0x%0x param=0x%0lx \n", ioctl_num, ioctl_param);
+	KNI_DBG("IOCTL num=0x%0x param=0x%0lx\n", ioctl_num, ioctl_param);
 
 	/*
 	 * Switch according to the ioctl called
@@ -563,13 +601,13 @@ kni_ioctl(struct inode *inode,
 		/* For test only, not used */
 		break;
 	case _IOC_NR(RTE_KNI_IOCTL_CREATE):
-		ret = kni_ioctl_create(ioctl_num, ioctl_param);
+		ret = kni_ioctl_create(net, ioctl_num, ioctl_param);
 		break;
 	case _IOC_NR(RTE_KNI_IOCTL_RELEASE):
-		ret = kni_ioctl_release(ioctl_num, ioctl_param);
+		ret = kni_ioctl_release(net, ioctl_num, ioctl_param);
 		break;
 	default:
-		KNI_DBG("IOCTL default \n");
+		KNI_DBG("IOCTL default\n");
 		break;
 	}
 
-- 
2.5.0