Re: why network devices don't do reference counting?

2007-09-27 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]>
Date: Thu, 27 Sep 2007 16:55:36 +0200 (CEST)

> 
> On Sep 27 2007 07:51, Stephen Hemminger wrote:
> >
> >You need every socket to close and all routes to go away including the 
> >routes through loopback device, and still there probably are control 
> >sockets buried inside ipv6 that hold ref count.
> >
> >IMHO the kernel should just admit that IPV6 can't be removed.
> 
> I cannot accept that. If ipv6.ko has a way to tack ipv6 structs onto all 
> sockets, interfaces and addresses, it should also be able to untack it 
> again.

Then you do the work and see how incredibly difficult the
implementation is, others have tried.  It's not trivial
and at best it's a very time consuming piece of work to
embark on.

Until then it's un-removable, plain as that :-)

I don't know why we're wasting our fingers discussing this
at all to be honest with you.
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Re: why network devices don't do reference counting?

2007-09-27 Thread David Miller
From: Helge Hafting <[EMAIL PROTECTED]>
Date: Thu, 27 Sep 2007 13:54:23 +0200

> Wouldn't it be enough to down all the interfaces and close all the sockets?
> No need to bring down every app.

And there are routes, and neighbour cache entries, and all sorts
of external references to the stack.  For example, if a packet
gets stuck in a device because the link just went down, that
can hold references to the ipv6 module from several angles.

But you have to add code to actually keep track of all of these
references and there is no such code in the ipv6 module at all
and it's a nontrivial time consuming job to implement it.
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-27 Thread Jan Engelhardt

On Sep 27 2007 07:51, Stephen Hemminger wrote:
>
>You need every socket to close and all routes to go away including the 
>routes through loopback device, and still there probably are control 
>sockets buried inside ipv6 that hold ref count.
>
>IMHO the kernel should just admit that IPV6 can't be removed.

I cannot accept that. If ipv6.ko has a way to tack ipv6 structs onto all 
sockets, interfaces and addresses, it should also be able to untack it 
again.
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-27 Thread Stephen Hemminger
On Thu, 27 Sep 2007 13:54:23 +0200
Helge Hafting <[EMAIL PROTECTED]> wrote:

> Stephen Hemminger wrote:
> > On Thu, 27 Sep 2007 00:18:55 +0200 (CEST)
> > Jan Engelhardt <[EMAIL PROTECTED]> wrote:
> >
> >   
> >> On Sep 26 2007 14:06, Stephen Hemminger wrote:
> >> 
> > No, network devices don't do reference counting.
> >   
>  Could you explain why, please?
> 
>  After `udevd` on boot loads lots of unused crap, i surrendered, and use
>  $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
>  there are lots of configs: udev, hotplug, modprobe, that somebody might
>  like to fix. But it came to the end with me. I just don't care. So,
>  please answer :)
>  
> >>> For hotplug and other reasons, the network developers decided that being
> >>> able to remove a network module at any time was a good thing. It works.
> >>>   
> >> Except that for ipv6.ko, it's all opposite. After modprobe,
> >> it already got a refcount like 8 and you're wondering how
> >> to get rid of that.
> >> 
> >
> > ipv6 is not a network driver, it is a protocol. You might be able to remove 
> > it if you zap
> > all the routes and applications, ...
> >   
> Wouldn't it be enough to down all the interfaces and close all the sockets?
> No need to bring down every app.

You need every socket to close and all routes to go away including the routes 
through
loopback device, and still there probably are control sockets buried inside ipv6
that hold ref count.

IMHO the kernel should just admit that IPV6 can't be removed.

--- a/net/ipv6/af_inet6.c   2007-09-26 16:28:01.0 -0700
+++ b/net/ipv6/af_inet6.c   2007-09-26 17:38:23.0 -0700
@@ -914,6 +914,9 @@ out_unregister_tcp_proto:
 }
 module_init(inet6_init);
 
+/* Disabled at present because it is impossible to remove all references */
+#ifdef IPV6_UNLOAD
+
 static void __exit inet6_exit(void)
 {
/* First of all disallow new sockets creation. */
@@ -952,5 +955,6 @@ static void __exit inet6_exit(void)
proto_unregister(_prot);
 }
 module_exit(inet6_exit);
+#endif
 
 MODULE_ALIAS_NETPROTO(PF_INET6);
--- a/net/ipv6/addrconf.c   2007-09-26 15:07:35.0 -0700
+++ b/net/ipv6/addrconf.c   2007-09-26 17:36:52.0 -0700
@@ -4255,6 +4255,7 @@ errout:
return err;
 }
 
+#ifdef IPV6_UNLOAD
 void __exit addrconf_cleanup(void)
 {
struct net_device *dev;
@@ -4308,3 +4309,4 @@ void __exit addrconf_cleanup(void)
proc_net_remove(_net, "if_inet6");
 #endif
 }
+#endif
--- a/net/ipv6/ipv6_sockglue.c  2007-09-26 15:07:35.0 -0700
+++ b/net/ipv6/ipv6_sockglue.c  2007-09-26 17:36:17.0 -0700
@@ -1132,7 +1132,9 @@ void __init ipv6_packet_init(void)
dev_add_pack(_packet_type);
 }
 
-void ipv6_packet_cleanup(void)
+#ifdef IPV6_UNLOAD
+void __exit ipv6_packet_cleanup(void)
 {
dev_remove_pack(_packet_type);
 }
+#endif
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-27 Thread Helge Hafting

Stephen Hemminger wrote:

On Thu, 27 Sep 2007 00:18:55 +0200 (CEST)
Jan Engelhardt <[EMAIL PROTECTED]> wrote:

  

On Sep 26 2007 14:06, Stephen Hemminger wrote:


No, network devices don't do reference counting.
  

Could you explain why, please?

After `udevd` on boot loads lots of unused crap, i surrendered, and use
$(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
there are lots of configs: udev, hotplug, modprobe, that somebody might
like to fix. But it came to the end with me. I just don't care. So,
please answer :)


For hotplug and other reasons, the network developers decided that being
able to remove a network module at any time was a good thing. It works.
  

Except that for ipv6.ko, it's all opposite. After modprobe,
it already got a refcount like 8 and you're wondering how
to get rid of that.



ipv6 is not a network driver, it is a protocol. You might be able to remove it 
if you zap
all the routes and applications, ...
  

Wouldn't it be enough to down all the interfaces and close all the sockets?
No need to bring down every app.

Helge Hafting
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-27 Thread Helge Hafting

Stephen Hemminger wrote:

On Thu, 27 Sep 2007 00:18:55 +0200 (CEST)
Jan Engelhardt [EMAIL PROTECTED] wrote:

  

On Sep 26 2007 14:06, Stephen Hemminger wrote:


No, network devices don't do reference counting.
  

Could you explain why, please?

After `udevd` on boot loads lots of unused crap, i surrendered, and use
$(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
there are lots of configs: udev, hotplug, modprobe, that somebody might
like to fix. But it came to the end with me. I just don't care. So,
please answer :)


For hotplug and other reasons, the network developers decided that being
able to remove a network module at any time was a good thing. It works.
  

Except that for ipv6.ko, it's all opposite. After modprobe,
it already got a refcount like 8 and you're wondering how
to get rid of that.



ipv6 is not a network driver, it is a protocol. You might be able to remove it 
if you zap
all the routes and applications, ...
  

Wouldn't it be enough to down all the interfaces and close all the sockets?
No need to bring down every app.

Helge Hafting
-
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-27 Thread Stephen Hemminger
On Thu, 27 Sep 2007 13:54:23 +0200
Helge Hafting [EMAIL PROTECTED] wrote:

 Stephen Hemminger wrote:
  On Thu, 27 Sep 2007 00:18:55 +0200 (CEST)
  Jan Engelhardt [EMAIL PROTECTED] wrote:
 

  On Sep 26 2007 14:06, Stephen Hemminger wrote:
  
  No, network devices don't do reference counting.

  Could you explain why, please?
 
  After `udevd` on boot loads lots of unused crap, i surrendered, and use
  $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
  there are lots of configs: udev, hotplug, modprobe, that somebody might
  like to fix. But it came to the end with me. I just don't care. So,
  please answer :)
  
  For hotplug and other reasons, the network developers decided that being
  able to remove a network module at any time was a good thing. It works.

  Except that for ipv6.ko, it's all opposite. After modprobe,
  it already got a refcount like 8 and you're wondering how
  to get rid of that.
  
 
  ipv6 is not a network driver, it is a protocol. You might be able to remove 
  it if you zap
  all the routes and applications, ...

 Wouldn't it be enough to down all the interfaces and close all the sockets?
 No need to bring down every app.

You need every socket to close and all routes to go away including the routes 
through
loopback device, and still there probably are control sockets buried inside ipv6
that hold ref count.

IMHO the kernel should just admit that IPV6 can't be removed.

--- a/net/ipv6/af_inet6.c   2007-09-26 16:28:01.0 -0700
+++ b/net/ipv6/af_inet6.c   2007-09-26 17:38:23.0 -0700
@@ -914,6 +914,9 @@ out_unregister_tcp_proto:
 }
 module_init(inet6_init);
 
+/* Disabled at present because it is impossible to remove all references */
+#ifdef IPV6_UNLOAD
+
 static void __exit inet6_exit(void)
 {
/* First of all disallow new sockets creation. */
@@ -952,5 +955,6 @@ static void __exit inet6_exit(void)
proto_unregister(tcpv6_prot);
 }
 module_exit(inet6_exit);
+#endif
 
 MODULE_ALIAS_NETPROTO(PF_INET6);
--- a/net/ipv6/addrconf.c   2007-09-26 15:07:35.0 -0700
+++ b/net/ipv6/addrconf.c   2007-09-26 17:36:52.0 -0700
@@ -4255,6 +4255,7 @@ errout:
return err;
 }
 
+#ifdef IPV6_UNLOAD
 void __exit addrconf_cleanup(void)
 {
struct net_device *dev;
@@ -4308,3 +4309,4 @@ void __exit addrconf_cleanup(void)
proc_net_remove(init_net, if_inet6);
 #endif
 }
+#endif
--- a/net/ipv6/ipv6_sockglue.c  2007-09-26 15:07:35.0 -0700
+++ b/net/ipv6/ipv6_sockglue.c  2007-09-26 17:36:17.0 -0700
@@ -1132,7 +1132,9 @@ void __init ipv6_packet_init(void)
dev_add_pack(ipv6_packet_type);
 }
 
-void ipv6_packet_cleanup(void)
+#ifdef IPV6_UNLOAD
+void __exit ipv6_packet_cleanup(void)
 {
dev_remove_pack(ipv6_packet_type);
 }
+#endif
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-27 Thread Jan Engelhardt

On Sep 27 2007 07:51, Stephen Hemminger wrote:

You need every socket to close and all routes to go away including the 
routes through loopback device, and still there probably are control 
sockets buried inside ipv6 that hold ref count.

IMHO the kernel should just admit that IPV6 can't be removed.

I cannot accept that. If ipv6.ko has a way to tack ipv6 structs onto all 
sockets, interfaces and addresses, it should also be able to untack it 
again.
-
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Re: why network devices don't do reference counting?

2007-09-27 Thread David Miller
From: Helge Hafting [EMAIL PROTECTED]
Date: Thu, 27 Sep 2007 13:54:23 +0200

 Wouldn't it be enough to down all the interfaces and close all the sockets?
 No need to bring down every app.

And there are routes, and neighbour cache entries, and all sorts
of external references to the stack.  For example, if a packet
gets stuck in a device because the link just went down, that
can hold references to the ipv6 module from several angles.

But you have to add code to actually keep track of all of these
references and there is no such code in the ipv6 module at all
and it's a nontrivial time consuming job to implement it.
-
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Re: why network devices don't do reference counting?

2007-09-27 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED]
Date: Thu, 27 Sep 2007 16:55:36 +0200 (CEST)

 
 On Sep 27 2007 07:51, Stephen Hemminger wrote:
 
 You need every socket to close and all routes to go away including the 
 routes through loopback device, and still there probably are control 
 sockets buried inside ipv6 that hold ref count.
 
 IMHO the kernel should just admit that IPV6 can't be removed.
 
 I cannot accept that. If ipv6.ko has a way to tack ipv6 structs onto all 
 sockets, interfaces and addresses, it should also be able to untack it 
 again.

Then you do the work and see how incredibly difficult the
implementation is, others have tried.  It's not trivial
and at best it's a very time consuming piece of work to
embark on.

Until then it's un-removable, plain as that :-)

I don't know why we're wasting our fingers discussing this
at all to be honest with you.
-
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the body of a message to [EMAIL PROTECTED]
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Re: why network devices don't do reference counting?

2007-09-26 Thread David Miller
From: Stephen Hemminger <[EMAIL PROTECTED]>
Date: Wed, 26 Sep 2007 15:33:30 -0700

> ipv6 is not a network driver, it is a protocol. You might be able to
> remove it if you zap all the routes and applications, ...

It is purposefully set to have a permanent elevated reference
count because it is not designed to be unloaded safely.

It has been unloadable forever.
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Stephen Hemminger
On Thu, 27 Sep 2007 00:18:55 +0200 (CEST)
Jan Engelhardt <[EMAIL PROTECTED]> wrote:

> 
> On Sep 26 2007 14:06, Stephen Hemminger wrote:
> >> >
> >> > No, network devices don't do reference counting.
> >> 
> >> Could you explain why, please?
> >> 
> >> After `udevd` on boot loads lots of unused crap, i surrendered, and use
> >> $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
> >> there are lots of configs: udev, hotplug, modprobe, that somebody might
> >> like to fix. But it came to the end with me. I just don't care. So,
> >> please answer :)
> >
> >For hotplug and other reasons, the network developers decided that being
> >able to remove a network module at any time was a good thing. It works.
> 
> Except that for ipv6.ko, it's all opposite. After modprobe,
> it already got a refcount like 8 and you're wondering how
> to get rid of that.

ipv6 is not a network driver, it is a protocol. You might be able to remove it 
if you zap
all the routes and applications, ...

-- 
Stephen Hemminger <[EMAIL PROTECTED]>
-
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Jan Engelhardt

On Sep 26 2007 14:06, Stephen Hemminger wrote:
>> >
>> > No, network devices don't do reference counting.
>> 
>> Could you explain why, please?
>> 
>> After `udevd` on boot loads lots of unused crap, i surrendered, and use
>> $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
>> there are lots of configs: udev, hotplug, modprobe, that somebody might
>> like to fix. But it came to the end with me. I just don't care. So,
>> please answer :)
>
>For hotplug and other reasons, the network developers decided that being
>able to remove a network module at any time was a good thing. It works.

Except that for ipv6.ko, it's all opposite. After modprobe,
it already got a refcount like 8 and you're wondering how
to get rid of that.

-
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Stephen Hemminger
On Wed, 26 Sep 2007 23:06:53 +0200
Oleg Verych <[EMAIL PROTECTED]> wrote:

> * Wed, 26 Sep 2007 08:37:05 -0700
> * Organization: Linux Foundation
> >
> > On Wed, 26 Sep 2007 08:53:27 +0100
> > "Jan Beulich" <[EMAIL PROTECTED]> wrote:
> >
> >> Otherwise 'modprobe -r' on a module having a dependency on bridge will
> >> implicitly unload bridge, bringing down all connectivity that was
> >> using bridges.
> >> 
> >> Signed-off-by: Jan Beulich <[EMAIL PROTECTED]>
> >>
> >
> > No, network devices don't do reference counting.
> 
> Could you explain why, please?
> 
> After `udevd` on boot loads lots of unused crap, i surrendered, and use
> $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
> there are lots of configs: udev, hotplug, modprobe, that somebody might
> like to fix. But it came to the end with me. I just don't care. So,
> please answer :)
> 

For hotplug and other reasons, the network developers decided that being
able to remove a network module at any time was a good thing. It works.

-- 
Stephen Hemminger <[EMAIL PROTECTED]>
-
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why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Oleg Verych
* Wed, 26 Sep 2007 08:37:05 -0700
* Organization: Linux Foundation
>
> On Wed, 26 Sep 2007 08:53:27 +0100
> "Jan Beulich" <[EMAIL PROTECTED]> wrote:
>
>> Otherwise 'modprobe -r' on a module having a dependency on bridge will
>> implicitly unload bridge, bringing down all connectivity that was
>> using bridges.
>> 
>> Signed-off-by: Jan Beulich <[EMAIL PROTECTED]>
>>
>
> No, network devices don't do reference counting.

Could you explain why, please?

After `udevd` on boot loads lots of unused crap, i surrendered, and use
$(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
there are lots of configs: udev, hotplug, modprobe, that somebody might
like to fix. But it came to the end with me. I just don't care. So,
please answer :)

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
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why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Oleg Verych
* Wed, 26 Sep 2007 08:37:05 -0700
* Organization: Linux Foundation

 On Wed, 26 Sep 2007 08:53:27 +0100
 Jan Beulich [EMAIL PROTECTED] wrote:

 Otherwise 'modprobe -r' on a module having a dependency on bridge will
 implicitly unload bridge, bringing down all connectivity that was
 using bridges.
 
 Signed-off-by: Jan Beulich [EMAIL PROTECTED]


 No, network devices don't do reference counting.

Could you explain why, please?

After `udevd` on boot loads lots of unused crap, i surrendered, and use
$(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
there are lots of configs: udev, hotplug, modprobe, that somebody might
like to fix. But it came to the end with me. I just don't care. So,
please answer :)

-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
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Please read the FAQ at  http://www.tux.org/lkml/


Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Stephen Hemminger
On Wed, 26 Sep 2007 23:06:53 +0200
Oleg Verych [EMAIL PROTECTED] wrote:

 * Wed, 26 Sep 2007 08:37:05 -0700
 * Organization: Linux Foundation
 
  On Wed, 26 Sep 2007 08:53:27 +0100
  Jan Beulich [EMAIL PROTECTED] wrote:
 
  Otherwise 'modprobe -r' on a module having a dependency on bridge will
  implicitly unload bridge, bringing down all connectivity that was
  using bridges.
  
  Signed-off-by: Jan Beulich [EMAIL PROTECTED]
 
 
  No, network devices don't do reference counting.
 
 Could you explain why, please?
 
 After `udevd` on boot loads lots of unused crap, i surrendered, and use
 $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
 there are lots of configs: udev, hotplug, modprobe, that somebody might
 like to fix. But it came to the end with me. I just don't care. So,
 please answer :)
 

For hotplug and other reasons, the network developers decided that being
able to remove a network module at any time was a good thing. It works.

-- 
Stephen Hemminger [EMAIL PROTECTED]
-
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Jan Engelhardt

On Sep 26 2007 14:06, Stephen Hemminger wrote:
 
  No, network devices don't do reference counting.
 
 Could you explain why, please?
 
 After `udevd` on boot loads lots of unused crap, i surrendered, and use
 $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
 there are lots of configs: udev, hotplug, modprobe, that somebody might
 like to fix. But it came to the end with me. I just don't care. So,
 please answer :)

For hotplug and other reasons, the network developers decided that being
able to remove a network module at any time was a good thing. It works.

Except that for ipv6.ko, it's all opposite. After modprobe,
it already got a refcount like 8 and you're wondering how
to get rid of that.

-
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Re: why network devices don't do reference counting? (Re: [PATCH] Module use count must be updated as bridges are created/destroyed)

2007-09-26 Thread Stephen Hemminger
On Thu, 27 Sep 2007 00:18:55 +0200 (CEST)
Jan Engelhardt [EMAIL PROTECTED] wrote:

 
 On Sep 26 2007 14:06, Stephen Hemminger wrote:
  
   No, network devices don't do reference counting.
  
  Could you explain why, please?
  
  After `udevd` on boot loads lots of unused crap, i surrendered, and use
  $(rmmod `lsmod | just first column`). Networing bravely wipes away. OK,
  there are lots of configs: udev, hotplug, modprobe, that somebody might
  like to fix. But it came to the end with me. I just don't care. So,
  please answer :)
 
 For hotplug and other reasons, the network developers decided that being
 able to remove a network module at any time was a good thing. It works.
 
 Except that for ipv6.ko, it's all opposite. After modprobe,
 it already got a refcount like 8 and you're wondering how
 to get rid of that.

ipv6 is not a network driver, it is a protocol. You might be able to remove it 
if you zap
all the routes and applications, ...

-- 
Stephen Hemminger [EMAIL PROTECTED]
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Re: why network devices don't do reference counting?

2007-09-26 Thread David Miller
From: Stephen Hemminger [EMAIL PROTECTED]
Date: Wed, 26 Sep 2007 15:33:30 -0700

 ipv6 is not a network driver, it is a protocol. You might be able to
 remove it if you zap all the routes and applications, ...

It is purposefully set to have a permanent elevated reference
count because it is not designed to be unloaded safely.

It has been unloadable forever.
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