[2.6.3] Sysfs breakage - tun.ko

[2.6.3] Sysfs breakage - tun.ko

[Nigel Kukard]

Hi,

Loading tun.ko module breaks on sysfs...

 > [root@localhost misc]# pwd
 > /sys/class/misc
 > [root@localhost misc]# ls
 > dac960_gam  device-mapper  net/tun  psaux
 > [root@localhost misc]# cd net\/tun
 > bash: cd: net/tun: No such file or directory
 > [root@localhost misc]#


Why not just make it in misc? why net/tun seeing as everything else is 
just dumped there. Patch below.



--- drivers/net/tun.c.old   2004-02-27 18:18:55.000000000 +0200
+++ drivers/net/tun.c       2004-02-27 18:19:02.000000000 +0200
@@ -605,7 +605,7 @@

  static struct miscdevice tun_miscdev = {
         .minor = TUN_MINOR,
-       .name = "net/tun",
+       .name = "tun",
         .fops = &tun_fops
  };

Re: [2.6.3] Sysfs breakage - tun.ko

[Kevin P. Fleming]

Nigel Kukard wrote:

> --- drivers/net/tun.c.old   2004-02-27 18:18:55.000000000 +0200
> +++ drivers/net/tun.c       2004-02-27 18:19:02.000000000 +0200
> @@ -605,7 +605,7 @@
> 
>  static struct miscdevice tun_miscdev = {
>         .minor = TUN_MINOR,
> -       .name = "net/tun",
> +       .name = "tun",
>         .fops = &tun_fops
>  };

This changed back and forth since the tun driver was added to the 
kernel; making this change will cause the devfs path to the tun node to 
change, and userspace applications expect it to be at /dev/misc/net/tun, 
whether that's right or wrong.

Re: [2.6.3] Sysfs breakage - tun.ko

[Nigel Kukard]

Nevermind if its right or wrong, it does not work in sysfs

-Nigel

On Mon, Mar 01, 2004 at 01:20:19PM -0700, Kevin P. Fleming wrote:
> Nigel Kukard wrote:
> 
> >--- drivers/net/tun.c.old   2004-02-27 18:18:55.000000000 +0200
> >+++ drivers/net/tun.c       2004-02-27 18:19:02.000000000 +0200
> >@@ -605,7 +605,7 @@
> >
> > static struct miscdevice tun_miscdev = {
> >        .minor = TUN_MINOR,
> >-       .name = "net/tun",
> >+       .name = "tun",
> >        .fops = &tun_fops
> > };
> 
> This changed back and forth since the tun driver was added to the 
> kernel; making this change will cause the devfs path to the tun node to 
> change, and userspace applications expect it to be at /dev/misc/net/tun, 
> whether that's right or wrong.

Re: [2.6.3] Sysfs breakage - tun.ko

[Chris Wright]

* Kevin P. Fleming (kpfleming@backtobasicsmgmt.com) wrote:
> Nigel Kukard wrote:
> 
> > --- drivers/net/tun.c.old   2004-02-27 18:18:55.000000000 +0200
> > +++ drivers/net/tun.c       2004-02-27 18:19:02.000000000 +0200
> > @@ -605,7 +605,7 @@
> > 
> >  static struct miscdevice tun_miscdev = {
> >         .minor = TUN_MINOR,
> > -       .name = "net/tun",
> > +       .name = "tun",
> >         .fops = &tun_fops
> >  };
> 
> This changed back and forth since the tun driver was added to the 
> kernel; making this change will cause the devfs path to the tun node to 
> change, and userspace applications expect it to be at /dev/misc/net/tun, 
> whether that's right or wrong.

Why don't you use:
	.devfs_name = "net/tun",

Or fix userspace apps?  Or switch to udev with devfs rules emulated and a
rule for the tun/tap driver?

thanks,
-chris
-- 
Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net

Re: [2.6.3] Sysfs breakage - tun.ko

[Kevin P. Fleming]

Chris Wright wrote:

> Why don't you use:
> 	.devfs_name = "net/tun",

That seems fine, if it will do the job.

> Or fix userspace apps?  Or switch to udev with devfs rules emulated and a
> rule for the tun/tap driver?

This is a stable kernel series; these kinds of userspace-breakage 
changes are not supposed to happen. Personally I have already started 
migrating my systems to udev, but it will take some time to complete 
that. Regardless, this would be a userspace-incompatible change if using 
.devfs_name won't do the job.

Re: [2.6.3] Sysfs breakage - tun.ko

[H. Peter Anvin]

Followup to:  <40439B03.4000505@backtobasicsmgmt.com>
By author:    "Kevin P. Fleming" <kpfleming@backtobasicsmgmt.com>
In newsgroup: linux.dev.kernel
>
> Nigel Kukard wrote:
> 
> > --- drivers/net/tun.c.old   2004-02-27 18:18:55.000000000 +0200
> > +++ drivers/net/tun.c       2004-02-27 18:19:02.000000000 +0200
> > @@ -605,7 +605,7 @@
> > 
> >  static struct miscdevice tun_miscdev = {
> >         .minor = TUN_MINOR,
> > -       .name = "net/tun",
> > +       .name = "tun",
> >         .fops = &tun_fops
> >  };
> 
> This changed back and forth since the tun driver was added to the 
> kernel; making this change will cause the devfs path to the tun node to 
> change, and userspace applications expect it to be at /dev/misc/net/tun, 
> whether that's right or wrong.
> 

Bullsh*t.

User-space apps expect it to be /dev/net/tun, which is the documented
path for this device node.  Anything else is a devfs bug (/dev/misc is
a devfs bug from beginning to end.)

	-hpa

Re: [2.6.3] Sysfs breakage - tun.ko

[Nigel Kukard]

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Nothing said solves the problem, the problem has got nothing to do with
devfs (only for compat reasons), the problem is that "net/tun" breaks
sysfs.
                                                                                                                                                                      
-Nigel


On Mon, Mar 01, 2004 at 01:20:19PM -0700, Kevin P. Fleming wrote:
> Nigel Kukard wrote:
> 
> >--- drivers/net/tun.c.old   2004-02-27 18:18:55.000000000 +0200
> >+++ drivers/net/tun.c       2004-02-27 18:19:02.000000000 +0200
> >@@ -605,7 +605,7 @@
> >
> > static struct miscdevice tun_miscdev = {
> >        .minor = TUN_MINOR,
> >-       .name = "net/tun",
> >+       .name = "tun",
> >        .fops = &tun_fops
> > };
> 
> This changed back and forth since the tun driver was added to the 
> kernel; making this change will cause the devfs path to the tun node to 
> change, and userspace applications expect it to be at /dev/misc/net/tun, 
> whether that's right or wrong.


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Re: [2.6.3] Sysfs breakage - tun.ko

[Chris Wright]

* Nigel Kukard (nkukard@lbsd.net) wrote:
> 
> Nothing said solves the problem, the problem has got nothing to do with
> devfs (only for compat reasons), the problem is that "net/tun" breaks
> sysfs.

Yes, why does this not work?  Keeps devfs legacy name, works fine with
udev, and makes proper dir in sysfs.

thanks,
-chris

===== drivers/net/tun.c 1.29 vs edited =====
--- 1.29/drivers/net/tun.c	Sat Jan 10 16:09:09 2004
+++ edited/drivers/net/tun.c	Tue Mar  2 12:05:30 2004
@@ -602,7 +602,8 @@
 
 static struct miscdevice tun_miscdev = {
 	.minor = TUN_MINOR,
-	.name = "net/tun",
+	.name = "tun",
+	.devfs_name = "net/tun",
 	.fops = &tun_fops
 };
 

Re: [2.6.3] Sysfs breakage - tun.ko

[Nigel Kukard]

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Thanks bud!

Hopefully it'll get included in 2.6.4  ;)

On Tue, Mar 02, 2004 at 06:28:34PM -0800, Chris Wright wrote:
> * Nigel Kukard (nkukard@lbsd.net) wrote:
> > 
> > Nothing said solves the problem, the problem has got nothing to do with
> > devfs (only for compat reasons), the problem is that "net/tun" breaks
> > sysfs.
> 
> Yes, why does this not work?  Keeps devfs legacy name, works fine with
> udev, and makes proper dir in sysfs.
> 
> thanks,
> -chris
> 
> ===== drivers/net/tun.c 1.29 vs edited =====
> --- 1.29/drivers/net/tun.c	Sat Jan 10 16:09:09 2004
> +++ edited/drivers/net/tun.c	Tue Mar  2 12:05:30 2004
> @@ -602,7 +602,8 @@
>  
>  static struct miscdevice tun_miscdev = {
>  	.minor = TUN_MINOR,
> -	.name = "net/tun",
> +	.name = "tun",
> +	.devfs_name = "net/tun",
>  	.fops = &tun_fops
>  };
>  

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