[PATCH] vhost-net: add module alias

[PATCH] vhost-net: add module alias

[Stephen Hemminger]

By adding the a module alias, programs (or users) won't have to explicitly
call modprobe. Vhost-net will always be available if built into the kernel.
It does require assigning a permanent minor number for depmod to work.
Choose one next to TUN since this driver is related to it.

Also, use C99 style initialization.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

---
 drivers/vhost/net.c        |    8 +++++---
 include/linux/miscdevice.h |    1 +
 2 files changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/vhost/net.c	2012-01-10 10:56:58.883179194 -0800
+++ b/drivers/vhost/net.c	2012-01-10 19:48:23.650225892 -0800
@@ -856,9 +856,9 @@ static const struct file_operations vhos
 };
 
 static struct miscdevice vhost_net_misc = {
-	MISC_DYNAMIC_MINOR,
-	"vhost-net",
-	&vhost_net_fops,
+	.minor = VHOST_NET_MINOR,
+	.name = "vhost-net",
+	.fops = &vhost_net_fops,
 };
 
 static int vhost_net_init(void)
@@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Michael S. Tsirkin");
 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
+MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
+MODULE_ALIAS("devname:vhost-net");
--- a/include/linux/miscdevice.h	2012-01-10 10:56:59.779189436 -0800
+++ b/include/linux/miscdevice.h	2012-01-10 19:49:56.091748210 -0800
@@ -31,6 +31,7 @@
 #define I2O_MINOR		166
 #define MICROCODE_MINOR		184
 #define TUN_MINOR		200
+#define VHOST_NET_MINOR		201
 #define MWAVE_MINOR		219	/* ACP/Mwave Modem */
 #define MPT_MINOR		220
 #define MPT2SAS_MINOR		221

Re: [PATCH] vhost-net: add module alias

[Michael Tokarev]

On 11.01.2012 08:54, Stephen Hemminger wrote:
> By adding the a module alias, programs (or users) won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.

Why do you think a statically-allocated device number will do any good
at all?  Static /dev is gone almost completely, at least on the systems
where whole virt stuff makes any sense, so you don't have pre-created
vhost-net device anymore, and hence this allocation makes no sense.
Just IMHO anyway.

Thanks,

/mjt

Re: [PATCH] vhost-net: add module alias

[Amos Kong]

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On Wed, Jan 11, 2012 at 12:54 PM, Stephen Hemminger
<shemminger@vyatta.com>wrote:

> By adding the a module alias, programs (or users) won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.
>
> Also, use C99 style initialization.
>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> ---
>  drivers/vhost/net.c        |    8 +++++---
>  include/linux/miscdevice.h |    1 +
>  2 files changed, 6 insertions(+), 3 deletions(-)
>
> --- a/drivers/vhost/net.c       2012-01-10 10:56:58.883179194 -0800
> +++ b/drivers/vhost/net.c       2012-01-10 19:48:23.650225892 -0800
> @@ -856,9 +856,9 @@ static const struct file_operations vhos
>  };
>
>  static struct miscdevice vhost_net_misc = {
> -       MISC_DYNAMIC_MINOR,
> -       "vhost-net",
> -       &vhost_net_fops,
> +       .minor = VHOST_NET_MINOR,
> +       .name = "vhost-net",
> +       .fops = &vhost_net_fops,
>  };
>
>  static int vhost_net_init(void)
> @@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
>  MODULE_LICENSE("GPL v2");
>  MODULE_AUTHOR("Michael S. Tsirkin");
>  MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
> +MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
> +MODULE_ALIAS("devname:vhost-net");
> --- a/include/linux/miscdevice.h        2012-01-10 10:56:59.779189436
> -0800
> +++ b/include/linux/miscdevice.h        2012-01-10 19:49:56.091748210
> -0800
> @@ -31,6 +31,7 @@
>  #define I2O_MINOR              166
>  #define MICROCODE_MINOR                184
>  #define TUN_MINOR              200
> +#define VHOST_NET_MINOR                201
>


CC: alan@linux.intel.com
CC: device@lanana.org

include/linux/miscdevice.h:
/*
 *      These allocations are managed by device@lanana.org. If you use an
 *      entry that is not in assigned your entry may well be moved and
 *      reassigned, or set dynamic if a fixed value is not justified.
 */


 #define MWAVE_MINOR            219     /* ACP/Mwave Modem */
>  #define MPT_MINOR              220
>  #define MPT2SAS_MINOR          221
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
>

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_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH] vhost-net: add module alias

[Stephen Hemminger]

On Wed, 11 Jan 2012 15:43:42 +0800
Amos Kong <kongjianjun@gmail.com> wrote:

> On Wed, Jan 11, 2012 at 12:54 PM, Stephen Hemminger
> <shemminger@vyatta.com>wrote:
> 
> > By adding the a module alias, programs (or users) won't have to explicitly
> > call modprobe. Vhost-net will always be available if built into the kernel.
> > It does require assigning a permanent minor number for depmod to work.
> > Choose one next to TUN since this driver is related to it.
> >
> > Also, use C99 style initialization.
> >
> > Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> >
> > ---
> >  drivers/vhost/net.c        |    8 +++++---
> >  include/linux/miscdevice.h |    1 +
> >  2 files changed, 6 insertions(+), 3 deletions(-)
> >
:
> /*
>  *      These allocations are managed by device@lanana.org. If you use an
>  *      entry that is not in assigned your entry may well be moved and
>  *      reassigned, or set dynamic if a fixed value is not justified.
>  */

Didn't that mailing address was ever used any more. Like many places
in kernel, the comment looked like a historical leftover.

Re: [PATCH] vhost-net: add module alias

[Stephen Hemminger]

On Wed, 11 Jan 2012 11:07:47 +0400
Michael Tokarev <mjt@tls.msk.ru> wrote:

> On 11.01.2012 08:54, Stephen Hemminger wrote:
> > By adding the a module alias, programs (or users) won't have to explicitly
> > call modprobe. Vhost-net will always be available if built into the kernel.
> > It does require assigning a permanent minor number for depmod to work.
> > Choose one next to TUN since this driver is related to it.
> 
> Why do you think a statically-allocated device number will do any good
> at all?  Static /dev is gone almost completely, at least on the systems
> where whole virt stuff makes any sense, so you don't have pre-created
> vhost-net device anymore, and hence this allocation makes no sense.
> Just IMHO anyway.

The statically allocated device number is required for the udev/module
autoloading to work. Probably the udev infrastructure needs a consistent
number to hang off of.

It looks like:
  * driver adds MODULE_ALIAS() for devname and character device
  * depmod scans modules and creates modules.devname (in /lib/modules)
  * udev uses modules.devname to autoload the module

$ /sbin/modinfo vhost_net
filename:       /lib/modules/3.2.0-net+/kernel/drivers/vhost/vhost_net.ko
alias:          devname:vhost-net
alias:          char-major-10-201
description:    Host kernel accelerator for virtio net
...

See also: https://lkml.org/lkml/2010/5/21/134

Re: [PATCH] vhost-net: add module alias

[Michael Tokarev]

On 11.01.2012 20:58, Stephen Hemminger wrote:
> On Wed, 11 Jan 2012 11:07:47 +0400
> Michael Tokarev <mjt@tls.msk.ru> wrote:
> 
>> On 11.01.2012 08:54, Stephen Hemminger wrote:
>>> By adding the a module alias, programs (or users) won't have to explicitly
>>> call modprobe. Vhost-net will always be available if built into the kernel.
>>> It does require assigning a permanent minor number for depmod to work.
>>> Choose one next to TUN since this driver is related to it.
>>
>> Why do you think a statically-allocated device number will do any good
>> at all?  Static /dev is gone almost completely, at least on the systems
>> where whole virt stuff makes any sense, so you don't have pre-created
>> vhost-net device anymore, and hence this allocation makes no sense.
>> Just IMHO anyway.
[]
> See also: https://lkml.org/lkml/2010/5/21/134

Aha.  So udev pre-creates statically-allocated devnodes nowadays:

 Udev will pick up the depmod created file on startup and create all the
 static device nodes which the kernel modules specify, so that these modules
 get automatically loaded when the device node is accessed...

This was the part I missed.  Now it all looks logically.

Thanks,

/mjt

Re: [PATCH] vhost-net: add module alias

[Kay Sievers]

On Wed, Jan 11, 2012 at 17:58, Stephen Hemminger <shemminger@vyatta.com> wrote:
> On Wed, 11 Jan 2012 11:07:47 +0400
> Michael Tokarev <mjt@tls.msk.ru> wrote:
>
>> On 11.01.2012 08:54, Stephen Hemminger wrote:
>> > By adding the a module alias, programs (or users) won't have to explicitly
>> > call modprobe. Vhost-net will always be available if built into the kernel.
>> > It does require assigning a permanent minor number for depmod to work.
>> > Choose one next to TUN since this driver is related to it.
>>
>> Why do you think a statically-allocated device number will do any good
>> at all?

It's totally fine to use them for single-instance devices. You are
right, enumerated devices must _never_ use any facility like that.
That would just be broken.

>> Static /dev is gone almost completely, at least on the systems
>> where whole virt stuff makes any sense, so you don't have pre-created
>> vhost-net device anymore, and hence this allocation makes no sense.
>> Just IMHO anyway.

It makes a lot of sense in this case. The kernel module files
advertise the dev_t, it's not stored anywhere else. UDev finds these
static numbers and does inplicit mkdev() for them.

> The statically allocated device number is required for the udev/module
> autoloading to work. Probably the udev infrastructure needs a consistent
> number to hang off of.

It does that properly.

Just check:
  $ cat /lib/modules/$(uname -r)/modules.devname
  # Device nodes to trigger on-demand module loading.
  fuse fuse c10:229
  btrfs btrfs-control c10:234
  ppp_generic ppp c108:0
  tun net/tun c10:200
  uinput uinput c10:223
  ...

Kay

[PATCH] vhost-net: add module alias (v2)

[Stephen Hemminger]

By adding the correct module alias, programs won't have to explicitly
call modprobe. Vhost-net will always be available if built into the kernel.
It does require assigning a permanent minor number for depmod to work.
Choose one next to TUN since this driver is related to it.

Also, use C99 style initialization.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

---
v2 - document minor number and make sure to not overlap

 Documentation/devices.txt  |    2 ++
 drivers/vhost/net.c        |    8 +++++---
 include/linux/miscdevice.h |    1 +
 3 files changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/vhost/net.c	2012-01-10 10:56:58.883179194 -0800
+++ b/drivers/vhost/net.c	2012-01-10 19:48:23.650225892 -0800
@@ -856,9 +856,9 @@ static const struct file_operations vhos
 };
 
 static struct miscdevice vhost_net_misc = {
-	MISC_DYNAMIC_MINOR,
-	"vhost-net",
-	&vhost_net_fops,
+	.minor = VHOST_NET_MINOR,
+	.name = "vhost-net",
+	.fops = &vhost_net_fops,
 };
 
 static int vhost_net_init(void)
@@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Michael S. Tsirkin");
 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
+MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
+MODULE_ALIAS("devname:vhost-net");
--- a/include/linux/miscdevice.h	2012-01-10 10:56:59.779189436 -0800
+++ b/include/linux/miscdevice.h	2012-01-11 09:13:20.803694316 -0800
@@ -42,6 +42,7 @@
 #define AUTOFS_MINOR		235
 #define MAPPER_CTRL_MINOR	236
 #define LOOP_CTRL_MINOR		237
+#define VHOST_NET_MINOR		238
 #define MISC_DYNAMIC_MINOR	255
 
 struct device;
--- a/Documentation/devices.txt	2012-01-10 10:56:53.399116518 -0800
+++ b/Documentation/devices.txt	2012-01-11 09:12:49.251197653 -0800
@@ -447,6 +447,8 @@ Your cooperation is appreciated.
 		234 = /dev/btrfs-control	Btrfs control device
 		235 = /dev/autofs	Autofs control device
 		236 = /dev/mapper/control	Device-Mapper control device
+		237 = /dev/vhost-net	Host kernel accelerator for virtio net
+
 		240-254			Reserved for local use
 		255			Reserved for MISC_DYNAMIC_MINOR

Re: [PATCH] vhost-net: add module alias (v2)

[Michael S. Tsirkin]

On Wed, Jan 11, 2012 at 09:16:53AM -0800, Stephen Hemminger wrote:
> By adding the correct module alias, programs won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.
> 
> Also, use C99 style initialization.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

I don't mind but this needs an Ack from Alan Cox
who made it dynamic in the first place,
see 79907d89c397b8bc2e05b347ec94e928ea919d33.

> ---
> v2 - document minor number and make sure to not overlap
> 
>  Documentation/devices.txt  |    2 ++
>  drivers/vhost/net.c        |    8 +++++---
>  include/linux/miscdevice.h |    1 +
>  3 files changed, 8 insertions(+), 3 deletions(-)
> 
> --- a/drivers/vhost/net.c	2012-01-10 10:56:58.883179194 -0800
> +++ b/drivers/vhost/net.c	2012-01-10 19:48:23.650225892 -0800
> @@ -856,9 +856,9 @@ static const struct file_operations vhos
>  };
>  
>  static struct miscdevice vhost_net_misc = {
> -	MISC_DYNAMIC_MINOR,
> -	"vhost-net",
> -	&vhost_net_fops,
> +	.minor = VHOST_NET_MINOR,
> +	.name = "vhost-net",
> +	.fops = &vhost_net_fops,
>  };
>  
>  static int vhost_net_init(void)
> @@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
>  MODULE_LICENSE("GPL v2");
>  MODULE_AUTHOR("Michael S. Tsirkin");
>  MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
> +MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
> +MODULE_ALIAS("devname:vhost-net");
> --- a/include/linux/miscdevice.h	2012-01-10 10:56:59.779189436 -0800
> +++ b/include/linux/miscdevice.h	2012-01-11 09:13:20.803694316 -0800
> @@ -42,6 +42,7 @@
>  #define AUTOFS_MINOR		235
>  #define MAPPER_CTRL_MINOR	236
>  #define LOOP_CTRL_MINOR		237
> +#define VHOST_NET_MINOR		238
>  #define MISC_DYNAMIC_MINOR	255
>  
>  struct device;
> --- a/Documentation/devices.txt	2012-01-10 10:56:53.399116518 -0800
> +++ b/Documentation/devices.txt	2012-01-11 09:12:49.251197653 -0800
> @@ -447,6 +447,8 @@ Your cooperation is appreciated.
>  		234 = /dev/btrfs-control	Btrfs control device
>  		235 = /dev/autofs	Autofs control device
>  		236 = /dev/mapper/control	Device-Mapper control device
> +		237 = /dev/vhost-net	Host kernel accelerator for virtio net
> +
>  		240-254			Reserved for local use
>  		255			Reserved for MISC_DYNAMIC_MINOR
>  
> 

Re: [PATCH] vhost-net: add module alias

[Michael S. Tsirkin]

On Wed, Jan 11, 2012 at 08:54:26AM -0800, Stephen Hemminger wrote:
> On Wed, 11 Jan 2012 15:43:42 +0800
> Amos Kong <kongjianjun@gmail.com> wrote:
> 
> > On Wed, Jan 11, 2012 at 12:54 PM, Stephen Hemminger
> > <shemminger@vyatta.com>wrote:
> > 
> > > By adding the a module alias, programs (or users) won't have to explicitly
> > > call modprobe. Vhost-net will always be available if built into the kernel.
> > > It does require assigning a permanent minor number for depmod to work.
> > > Choose one next to TUN since this driver is related to it.
> > >
> > > Also, use C99 style initialization.
> > >
> > > Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> > >
> > > ---
> > >  drivers/vhost/net.c        |    8 +++++---
> > >  include/linux/miscdevice.h |    1 +
> > >  2 files changed, 6 insertions(+), 3 deletions(-)
> > >
> :
> > /*
> >  *      These allocations are managed by device@lanana.org. If you use an
> >  *      entry that is not in assigned your entry may well be moved and
> >  *      reassigned, or set dynamic if a fixed value is not justified.
> >  */
> 
> Didn't that mailing address was ever used any more. Like many places
> in kernel, the comment looked like a historical leftover.

This was only added in 2010, see
79907d89c397b8bc2e05b347ec94e928ea919d33.
That said at least lanana.org web site seems to be down.

Alan, any idea?

-- 
MST

Re: [PATCH] vhost-net: add module alias (v2)

[Ben Hutchings]

On Wed, 2012-01-11 at 09:16 -0800, Stephen Hemminger wrote:
> By adding the correct module alias, programs won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.
> 
> Also, use C99 style initialization.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> 
> ---
> v2 - document minor number and make sure to not overlap
[...]
> --- a/include/linux/miscdevice.h	2012-01-10 10:56:59.779189436 -0800
> +++ b/include/linux/miscdevice.h	2012-01-11 09:13:20.803694316 -0800
> @@ -42,6 +42,7 @@
>  #define AUTOFS_MINOR		235
>  #define MAPPER_CTRL_MINOR	236
>  #define LOOP_CTRL_MINOR		237
> +#define VHOST_NET_MINOR		238
>  #define MISC_DYNAMIC_MINOR	255
>  
>  struct device;
> --- a/Documentation/devices.txt	2012-01-10 10:56:53.399116518 -0800
> +++ b/Documentation/devices.txt	2012-01-11 09:12:49.251197653 -0800
> @@ -447,6 +447,8 @@ Your cooperation is appreciated.
>  		234 = /dev/btrfs-control	Btrfs control device
>  		235 = /dev/autofs	Autofs control device
>  		236 = /dev/mapper/control	Device-Mapper control device
> +		237 = /dev/vhost-net	Host kernel accelerator for virtio net
[...]

238 != 237.  It looks like someone forgot to add loopctrl here.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: [PATCH] vhost-net: add module alias (v2)

[Zhi Yong Wu]

On Thu, Jan 12, 2012 at 1:16 AM, Stephen Hemminger
<shemminger@vyatta.com> wrote:
> By adding the correct module alias, programs won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.
>
> Also, use C99 style initialization.
>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> ---
> v2 - document minor number and make sure to not overlap
>
>  Documentation/devices.txt  |    2 ++
>  drivers/vhost/net.c        |    8 +++++---
>  include/linux/miscdevice.h |    1 +
>  3 files changed, 8 insertions(+), 3 deletions(-)
>
> --- a/drivers/vhost/net.c       2012-01-10 10:56:58.883179194 -0800
> +++ b/drivers/vhost/net.c       2012-01-10 19:48:23.650225892 -0800
> @@ -856,9 +856,9 @@ static const struct file_operations vhos
>  };
>
>  static struct miscdevice vhost_net_misc = {
> -       MISC_DYNAMIC_MINOR,
> -       "vhost-net",
> -       &vhost_net_fops,
> +       .minor = VHOST_NET_MINOR,
> +       .name = "vhost-net",
> +       .fops = &vhost_net_fops,
>  };
>
>  static int vhost_net_init(void)
> @@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
>  MODULE_LICENSE("GPL v2");
>  MODULE_AUTHOR("Michael S. Tsirkin");
>  MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
> +MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
> +MODULE_ALIAS("devname:vhost-net");
> --- a/include/linux/miscdevice.h        2012-01-10 10:56:59.779189436 -0800
> +++ b/include/linux/miscdevice.h        2012-01-11 09:13:20.803694316 -0800
> @@ -42,6 +42,7 @@
>  #define AUTOFS_MINOR           235
>  #define MAPPER_CTRL_MINOR      236
>  #define LOOP_CTRL_MINOR                237
> +#define VHOST_NET_MINOR                238
>  #define MISC_DYNAMIC_MINOR     255
>
>  struct device;
> --- a/Documentation/devices.txt 2012-01-10 10:56:53.399116518 -0800
> +++ b/Documentation/devices.txt 2012-01-11 09:12:49.251197653 -0800
> @@ -447,6 +447,8 @@ Your cooperation is appreciated.
>                234 = /dev/btrfs-control        Btrfs control device
>                235 = /dev/autofs       Autofs control device
>                236 = /dev/mapper/control       Device-Mapper control device
> +               237 = /dev/vhost-net    Host kernel accelerator for virtio net
> +
238? The stuff for LOOP_CTRL seems to be missing?

>                240-254                 Reserved for local use
>                255                     Reserved for MISC_DYNAMIC_MINOR
>
>
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization



-- 
Regards,

Zhi Yong Wu

[PATCH] vhost-net: add module alias (v2.1)

[Stephen Hemminger]

Subject: vhost-net: add module alias (v2.1)

By adding some module aliases, programs (or users) won't have to explicitly
call modprobe. Vhost-net will always be available if built into the kernel.
It does require assigning a permanent minor number for depmod to work.

Also:
  - use C99 style initialization.
  - add missing entry in documentation for loop-control

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

---
2.1 - add missing documentation for loop control as well

 Documentation/devices.txt  |    3 +++
 drivers/vhost/net.c        |    8 +++++---
 include/linux/miscdevice.h |    1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

--- a/drivers/vhost/net.c	2012-01-10 10:56:58.883179194 -0800
+++ b/drivers/vhost/net.c	2012-01-10 19:48:23.650225892 -0800
@@ -856,9 +856,9 @@ static const struct file_operations vhos
 };
 
 static struct miscdevice vhost_net_misc = {
-	MISC_DYNAMIC_MINOR,
-	"vhost-net",
-	&vhost_net_fops,
+	.minor = VHOST_NET_MINOR,
+	.name = "vhost-net",
+	.fops = &vhost_net_fops,
 };
 
 static int vhost_net_init(void)
@@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Michael S. Tsirkin");
 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
+MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
+MODULE_ALIAS("devname:vhost-net");
--- a/include/linux/miscdevice.h	2012-01-10 10:56:59.779189436 -0800
+++ b/include/linux/miscdevice.h	2012-01-11 09:13:20.803694316 -0800
@@ -42,6 +42,7 @@
 #define AUTOFS_MINOR		235
 #define MAPPER_CTRL_MINOR	236
 #define LOOP_CTRL_MINOR		237
+#define VHOST_NET_MINOR		238
 #define MISC_DYNAMIC_MINOR	255
 
 struct device;
--- a/Documentation/devices.txt	2012-01-10 10:56:53.399116518 -0800
+++ b/Documentation/devices.txt	2012-01-11 13:17:07.882113340 -0800
@@ -447,6 +447,9 @@ Your cooperation is appreciated.
 		234 = /dev/btrfs-control	Btrfs control device
 		235 = /dev/autofs	Autofs control device
 		236 = /dev/mapper/control	Device-Mapper control device
+		237 = /dev/loop-control Loopback control device
+		238 = /dev/vhost-net	Host kernel accelerator for virtio net
+
 		240-254			Reserved for local use
 		255			Reserved for MISC_DYNAMIC_MINOR

Re: [PATCH] vhost-net: add module alias (v2)

[Thadeu Lima de Souza Cascardo]

On Wed, Jan 11, 2012 at 09:16:53AM -0800, Stephen Hemminger wrote:
> By adding the correct module alias, programs won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.
> 
> Also, use C99 style initialization.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> 
> ---
> v2 - document minor number and make sure to not overlap
> 
>  Documentation/devices.txt  |    2 ++
>  drivers/vhost/net.c        |    8 +++++---
>  include/linux/miscdevice.h |    1 +
>  3 files changed, 8 insertions(+), 3 deletions(-)
> 
> --- a/drivers/vhost/net.c	2012-01-10 10:56:58.883179194 -0800
> +++ b/drivers/vhost/net.c	2012-01-10 19:48:23.650225892 -0800
> @@ -856,9 +856,9 @@ static const struct file_operations vhos
>  };
> 
>  static struct miscdevice vhost_net_misc = {
> -	MISC_DYNAMIC_MINOR,
> -	"vhost-net",
> -	&vhost_net_fops,
> +	.minor = VHOST_NET_MINOR,
> +	.name = "vhost-net",
> +	.fops = &vhost_net_fops,
>  };
> 
>  static int vhost_net_init(void)
> @@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
>  MODULE_LICENSE("GPL v2");
>  MODULE_AUTHOR("Michael S. Tsirkin");
>  MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
> +MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
> +MODULE_ALIAS("devname:vhost-net");
> --- a/include/linux/miscdevice.h	2012-01-10 10:56:59.779189436 -0800
> +++ b/include/linux/miscdevice.h	2012-01-11 09:13:20.803694316 -0800
> @@ -42,6 +42,7 @@
>  #define AUTOFS_MINOR		235
>  #define MAPPER_CTRL_MINOR	236
>  #define LOOP_CTRL_MINOR		237
> +#define VHOST_NET_MINOR		238
>  #define MISC_DYNAMIC_MINOR	255
> 
>  struct device;
> --- a/Documentation/devices.txt	2012-01-10 10:56:53.399116518 -0800
> +++ b/Documentation/devices.txt	2012-01-11 09:12:49.251197653 -0800
> @@ -447,6 +447,8 @@ Your cooperation is appreciated.
>  		234 = /dev/btrfs-control	Btrfs control device
>  		235 = /dev/autofs	Autofs control device
>  		236 = /dev/mapper/control	Device-Mapper control device
> +		237 = /dev/vhost-net	Host kernel accelerator for virtio net
> +
>  		240-254			Reserved for local use
>  		255			Reserved for MISC_DYNAMIC_MINOR
> 
> 

You added vhost-net minor as 238 in the code and 237 in the
documentation. That's because loop-control is missing from the docs.

Regards.
Cascardo.

> 
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH] vhost-net: add module alias (v2.1)

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Wed, 11 Jan 2012 21:30:38 -0800

> Subject: vhost-net: add module alias (v2.1)
> 
> By adding some module aliases, programs (or users) won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> 
> Also:
>   - use C99 style initialization.
>   - add missing entry in documentation for loop-control
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

ACKs, NACKs?  What is happening here?

Re: [PATCH] vhost-net: add module alias (v2.1)

[Kay Sievers]

On Fri, Jan 13, 2012 at 05:07, David Miller <davem@davemloft.net> wrote:
> From: Stephen Hemminger <shemminger@vyatta.com>
> Date: Wed, 11 Jan 2012 21:30:38 -0800
>
>> Subject: vhost-net: add module alias (v2.1)
>>
>> By adding some module aliases, programs (or users) won't have to explicitly
>> call modprobe. Vhost-net will always be available if built into the kernel.
>> It does require assigning a permanent minor number for depmod to work.
>>
>> Also:
>>   - use C99 style initialization.
>>   - add missing entry in documentation for loop-control
>>
>> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> ACKs, NACKs?  What is happening here?

In general, static minors are acceptable and very useful to make
on-demand loading of kernel modules working. They should be used only
for single-instance devices though, which usually means: One single
static device name associated with a module.

That looks all fine here, and for what it's worth:
  Acked-By: Kay Sievers <kay.sievers@vrfy.org>

Kay
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
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Re: [PATCH] vhost-net: add module alias (v2.1)

[David Miller]

From: Kay Sievers <kay.sievers@vrfy.org>
Date: Fri, 13 Jan 2012 05:19:05 +0100

> On Fri, Jan 13, 2012 at 05:07, David Miller <davem@davemloft.net> wrote:
>> From: Stephen Hemminger <shemminger@vyatta.com>
>> Date: Wed, 11 Jan 2012 21:30:38 -0800
>>
>>> Subject: vhost-net: add module alias (v2.1)
>>>
>>> By adding some module aliases, programs (or users) won't have to explicitly
>>> call modprobe. Vhost-net will always be available if built into the kernel.
>>> It does require assigning a permanent minor number for depmod to work.
>>>
>>> Also:
>>>   - use C99 style initialization.
>>>   - add missing entry in documentation for loop-control
>>>
>>> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>>
>> ACKs, NACKs?  What is happening here?
> 
> In general, static minors are acceptable and very useful to make
> on-demand loading of kernel modules working. They should be used only
> for single-instance devices though, which usually means: One single
> static device name associated with a module.
> 
> That looks all fine here, and for what it's worth:
>   Acked-By: Kay Sievers <kay.sievers@vrfy.org>

Ok, applied, thanks everyone.

Re: [PATCH] vhost-net: add module alias (v2.1)

[Michael S. Tsirkin]

On Thu, Jan 12, 2012 at 08:07:01PM -0800, David Miller wrote:
> From: Stephen Hemminger <shemminger@vyatta.com>
> Date: Wed, 11 Jan 2012 21:30:38 -0800
> 
> > Subject: vhost-net: add module alias (v2.1)
> > 
> > By adding some module aliases, programs (or users) won't have to explicitly
> > call modprobe. Vhost-net will always be available if built into the kernel.
> > It does require assigning a permanent minor number for depmod to work.
> > 
> > Also:
> >   - use C99 style initialization.
> >   - add missing entry in documentation for loop-control
> > 
> > Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> 
> ACKs, NACKs?  What is happening here?

I would like an Ack from Alan Cox who switched vhost-net
to a dynamic minor in the first place, in commit
79907d89c397b8bc2e05b347ec94e928ea919d33.

-- 
MST

Re: [PATCH] vhost-net: add module alias (v2.1)

[Alan Cox]

> > ACKs, NACKs?  What is happening here?
> 
> I would like an Ack from Alan Cox who switched vhost-net
> to a dynamic minor in the first place, in commit
> 79907d89c397b8bc2e05b347ec94e928ea919d33.

Sorry device@lanana.org isn't yet back from the kernel hack incident.

I don't read netdev so someone needs to summarise the issue and send me
a copy of the patch to look at.

Alan

Re: [PATCH] vhost-net: add module alias

[Avi Kivity]

On 01/11/2012 06:54 AM, Stephen Hemminger wrote:
> By adding the a module alias, programs (or users) won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> Choose one next to TUN since this driver is related to it.

Statically allocated numbers have to go through lanana, no?

This increases the security exposure and the kernel footprint for hosts
that don't want vhost-net.

-- 
error compiling committee.c: too many arguments to function

Re: [PATCH] vhost-net: add module alias (v2.1)

[Stephen Hemminger]

On Mon, 16 Jan 2012 12:26:45 +0000
Alan Cox <alan@linux.intel.com> wrote:

> > > ACKs, NACKs?  What is happening here?
> > 
> > I would like an Ack from Alan Cox who switched vhost-net
> > to a dynamic minor in the first place, in commit
> > 79907d89c397b8bc2e05b347ec94e928ea919d33.
> 
> Sorry device@lanana.org isn't yet back from the kernel hack incident.
> 
> I don't read netdev so someone needs to summarise the issue and send me
> a copy of the patch to look at.
> 
> Alan

Subject: vhost-net: add module alias (v2.1)

By adding some module aliases, programs (or users) won't have to explicitly
call modprobe. Vhost-net will always be available if built into the kernel.
It does require assigning a permanent minor number for depmod to work.

Also:
  - use C99 style initialization.
  - add missing entry in documentation for loop-control

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

---
2.1 - add missing documentation for loop control as well

 Documentation/devices.txt  |    3 +++
 drivers/vhost/net.c        |    8 +++++---
 include/linux/miscdevice.h |    1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

--- a/drivers/vhost/net.c	2012-01-12 14:14:25.681815487 -0800
+++ b/drivers/vhost/net.c	2012-01-12 18:09:56.810680816 -0800
@@ -856,9 +856,9 @@ static const struct file_operations vhos
 };
 
 static struct miscdevice vhost_net_misc = {
-	MISC_DYNAMIC_MINOR,
-	"vhost-net",
-	&vhost_net_fops,
+	.minor = VHOST_NET_MINOR,
+	.name = "vhost-net",
+	.fops = &vhost_net_fops,
 };
 
 static int vhost_net_init(void)
@@ -879,3 +879,5 @@ MODULE_VERSION("0.0.1");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Michael S. Tsirkin");
 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
+MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
+MODULE_ALIAS("devname:vhost-net");
--- a/include/linux/miscdevice.h	2012-01-12 14:14:25.725815981 -0800
+++ b/include/linux/miscdevice.h	2012-01-12 18:09:56.810680816 -0800
@@ -42,6 +42,7 @@
 #define AUTOFS_MINOR		235
 #define MAPPER_CTRL_MINOR	236
 #define LOOP_CTRL_MINOR		237
+#define VHOST_NET_MINOR		238
 #define MISC_DYNAMIC_MINOR	255
 
 struct device;
--- a/Documentation/devices.txt	2012-01-12 14:14:25.701815712 -0800
+++ b/Documentation/devices.txt	2012-01-12 18:09:56.814680860 -0800
@@ -447,6 +447,9 @@ Your cooperation is appreciated.
 		234 = /dev/btrfs-control	Btrfs control device
 		235 = /dev/autofs	Autofs control device
 		236 = /dev/mapper/control	Device-Mapper control device
+		237 = /dev/loop-control Loopback control device
+		238 = /dev/vhost-net	Host kernel accelerator for virtio net
+
 		240-254			Reserved for local use
 		255			Reserved for MISC_DYNAMIC_MINOR

Re: [PATCH] vhost-net: add module alias (v2.1)

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Mon, 16 Jan 2012 07:52:36 -0800

> On Mon, 16 Jan 2012 12:26:45 +0000
> Alan Cox <alan@linux.intel.com> wrote:
> 
>> > > ACKs, NACKs?  What is happening here?
>> > 
>> > I would like an Ack from Alan Cox who switched vhost-net
>> > to a dynamic minor in the first place, in commit
>> > 79907d89c397b8bc2e05b347ec94e928ea919d33.
>> 
>> Sorry device@lanana.org isn't yet back from the kernel hack incident.
>> 
>> I don't read netdev so someone needs to summarise the issue and send me
>> a copy of the patch to look at.
>> 
>> Alan
> 
> Subject: vhost-net: add module alias (v2.1)
> 
> By adding some module aliases, programs (or users) won't have to explicitly
> call modprobe. Vhost-net will always be available if built into the kernel.
> It does require assigning a permanent minor number for depmod to work.
> 
> Also:
>   - use C99 style initialization.
>   - add missing entry in documentation for loop-control
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

I already applied your first patch, so you need to give me something
relative to apply on top of your original one.

And it also shows that you're really not generating these patches
against current 'net', otherwise you'd have noticed your other patch
already there.

Re: [PATCH] vhost-net: add module alias (v2.1)

[Alan Cox]

> Also:
>   - use C99 style initialization.
>   - add missing entry in documentation for loop-control
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

For the device allocation

Acked-by: Alan Cox <devices@lanana.org>