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

["Zhang, Helin" <helin.zhang@intel.com>]

Hi Dex

Two comments inlined. Thank you very much for the really good contribution to KNI!

Regards,
Helin

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Dex Chen
> Sent: Thursday, July 2, 2015 6:12 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH] kni: allow per-net instances
> 
> 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 differnt 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>
> ---
>  lib/librte_eal/linuxapp/kni/kni_misc.c | 129
> ++++++++++++++++++++++-----------
>  1 file changed, 85 insertions(+), 44 deletions(-)
> 
> diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c
> b/lib/librte_eal/linuxapp/kni/kni_misc.c
> index 2e9fa89..5ba8ab8 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 +93,48 @@ 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 {
> +	volatile 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 __net_exit void kni_exit_net(struct net *net) {
> +	/*
> +	 * Nothing to do here.
> +	 * Assuming all cleanup jobs were done in kni_release().
> +	 */
> +}
Agree with Stephen, kernel should handle it well.

> +
> +static struct pernet_operations kni_net_ops = {
> +	.init = kni_init_net,
> +	.exit = kni_exit_net,
> +	.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) {
> @@ -114,8 +147,9 @@ kni_init(void)
>  		return -EPERM;
>  	}
> 
> -	/* Clear the bit of device in use */
> -	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &device_in_use);
> +	rc = register_pernet_subsys(&kni_net_ops);
> +	if (rc)
> +		goto out;
> 
>  	/* Configure the lo mode according to the input parameter */
>  	kni_net_config_lo_mode(lo_mode);
> @@ -123,11 +157,16 @@ kni_init(void)
>  	KNI_PRINT("######## DPDK kni module loaded  ########\n");
> 
>  	return 0;
> +
> +out:
> +	misc_deregister(&kni_misc);
> +	return rc;
>  }
> 
>  static void __exit
>  kni_exit(void)
>  {
> +	unregister_pernet_subsys(&kni_net_ops);
Should above 'unregsiter' be moved after 'misc_deregister()'?

>  	misc_deregister(&kni_misc);
>  	KNI_PRINT("####### DPDK kni module unloaded  #######\n");  } @@
> -151,19 +190,22 @@ kni_parse_kthread_mode(void)  static int