[PATCH] Bluetooth: allocate static minor for vhci

[PATCH] Bluetooth: allocate static minor for vhci

[Lucas De Marchi]

Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
driver) added the module alias to hci_vhci module so it's possible to
create the /dev/vhci node. However creating an alias without
specifying the minor doesn't allow us to create the node ahead,
triggerring module auto-load when it's first accessed.

Starting with depmod from kmod 16 we started to warn if there's a
devname alias without specifying the major and minor.

Let's do the same done for uhid, kvm, fuse and others, specifying a
fixed minor. In systems with systemd as the init the following will
happen: on early boot systemd will call "kmod static-nodes" to read
/lib/modules/$(uname -r)/modules.devname and then create the nodes. When
first accessed these "dead" nodes will trigger the module loading.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
---
 drivers/bluetooth/hci_vhci.c | 3 ++-
 include/linux/miscdevice.h   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
index 1ef6990..add1c6a 100644
--- a/drivers/bluetooth/hci_vhci.c
+++ b/drivers/bluetooth/hci_vhci.c
@@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
 static struct miscdevice vhci_miscdev= {
 	.name	= "vhci",
 	.fops	= &vhci_fops,
-	.minor	= MISC_DYNAMIC_MINOR,
+	.minor	= VHCI_MINOR,
 };
 
 static int __init vhci_init(void)
@@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
 MODULE_VERSION(VERSION);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("devname:vhci");
+MODULE_ALIAS_MISCDEV(VHCI_MINOR);
diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 3737f72..846a317 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -48,6 +48,7 @@
 #define LOOP_CTRL_MINOR		237
 #define VHOST_NET_MINOR		238
 #define UHID_MINOR		239
+#define VHCI_MINOR		240
 #define MISC_DYNAMIC_MINOR	255
 
 struct device;
-- 
1.9.0

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Marcel Holtmann]

Hi Lucas,

> Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
> driver) added the module alias to hci_vhci module so it's possible to
> create the /dev/vhci node. However creating an alias without
> specifying the minor doesn't allow us to create the node ahead,
> triggerring module auto-load when it's first accessed.
> 
> Starting with depmod from kmod 16 we started to warn if there's a
> devname alias without specifying the major and minor.
> 
> Let's do the same done for uhid, kvm, fuse and others, specifying a
> fixed minor. In systems with systemd as the init the following will
> happen: on early boot systemd will call "kmod static-nodes" to read
> /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
> first accessed these "dead" nodes will trigger the module loading.
> 
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> drivers/bluetooth/hci_vhci.c | 3 ++-
> include/linux/miscdevice.h   | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> index 1ef6990..add1c6a 100644
> --- a/drivers/bluetooth/hci_vhci.c
> +++ b/drivers/bluetooth/hci_vhci.c
> @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
> static struct miscdevice vhci_miscdev= {
> 	.name	= "vhci",
> 	.fops	= &vhci_fops,
> -	.minor	= MISC_DYNAMIC_MINOR,
> +	.minor	= VHCI_MINOR,
> };
> 
> static int __init vhci_init(void)
> @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
> MODULE_VERSION(VERSION);
> MODULE_LICENSE("GPL");
> MODULE_ALIAS("devname:vhci");
> +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
> diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> index 3737f72..846a317 100644
> --- a/include/linux/miscdevice.h
> +++ b/include/linux/miscdevice.h
> @@ -48,6 +48,7 @@
> #define LOOP_CTRL_MINOR		237
> #define VHOST_NET_MINOR		238
> #define UHID_MINOR		239
> +#define VHCI_MINOR		240
> #define MISC_DYNAMIC_MINOR	255

you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.

Regards

Marcel

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Lucas De Marchi]

[ CC'ing Kay and Greg ]

On Mon, Feb 17, 2014 at 08:34:32AM -0800, Marcel Holtmann wrote:
> Hi Lucas,
> 
> > Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
> > driver) added the module alias to hci_vhci module so it's possible to
> > create the /dev/vhci node. However creating an alias without
> > specifying the minor doesn't allow us to create the node ahead,
> > triggerring module auto-load when it's first accessed.
> > 
> > Starting with depmod from kmod 16 we started to warn if there's a
> > devname alias without specifying the major and minor.
> > 
> > Let's do the same done for uhid, kvm, fuse and others, specifying a
> > fixed minor. In systems with systemd as the init the following will
> > happen: on early boot systemd will call "kmod static-nodes" to read
> > /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
> > first accessed these "dead" nodes will trigger the module loading.
> > 
> > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> > ---
> > drivers/bluetooth/hci_vhci.c | 3 ++-
> > include/linux/miscdevice.h   | 1 +
> > 2 files changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> > index 1ef6990..add1c6a 100644
> > --- a/drivers/bluetooth/hci_vhci.c
> > +++ b/drivers/bluetooth/hci_vhci.c
> > @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
> > static struct miscdevice vhci_miscdev= {
> > 	.name	= "vhci",
> > 	.fops	= &vhci_fops,
> > -	.minor	= MISC_DYNAMIC_MINOR,
> > +	.minor	= VHCI_MINOR,
> > };
> > 
> > static int __init vhci_init(void)
> > @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
> > MODULE_VERSION(VERSION);
> > MODULE_LICENSE("GPL");
> > MODULE_ALIAS("devname:vhci");
> > +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
> > diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> > index 3737f72..846a317 100644
> > --- a/include/linux/miscdevice.h
> > +++ b/include/linux/miscdevice.h
> > @@ -48,6 +48,7 @@
> > #define LOOP_CTRL_MINOR		237
> > #define VHOST_NET_MINOR		238
> > #define UHID_MINOR		239
> > +#define VHCI_MINOR		240
> > #define MISC_DYNAMIC_MINOR	255
> 
> you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.

I haven't seen that. So, are we out of minors or.. can I use e.g.
142, 129 or the ones below 128?

Kay? Greg?

-- 
Lucas De Marchi

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Kay Sievers]

On Mon, Feb 17, 2014 at 8:01 PM, Lucas De Marchi
<lucas.demarchi@intel.com> wrote:
> [ CC'ing Kay and Greg ]
>
> On Mon, Feb 17, 2014 at 08:34:32AM -0800, Marcel Holtmann wrote:
>> Hi Lucas,
>>
>> > Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
>> > driver) added the module alias to hci_vhci module so it's possible to
>> > create the /dev/vhci node. However creating an alias without
>> > specifying the minor doesn't allow us to create the node ahead,
>> > triggerring module auto-load when it's first accessed.
>> >
>> > Starting with depmod from kmod 16 we started to warn if there's a
>> > devname alias without specifying the major and minor.
>> >
>> > Let's do the same done for uhid, kvm, fuse and others, specifying a
>> > fixed minor. In systems with systemd as the init the following will
>> > happen: on early boot systemd will call "kmod static-nodes" to read
>> > /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
>> > first accessed these "dead" nodes will trigger the module loading.
>> >
>> > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
>> > ---
>> > drivers/bluetooth/hci_vhci.c | 3 ++-
>> > include/linux/miscdevice.h   | 1 +
>> > 2 files changed, 3 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
>> > index 1ef6990..add1c6a 100644
>> > --- a/drivers/bluetooth/hci_vhci.c
>> > +++ b/drivers/bluetooth/hci_vhci.c
>> > @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
>> > static struct miscdevice vhci_miscdev= {
>> >     .name   = "vhci",
>> >     .fops   = &vhci_fops,
>> > -   .minor  = MISC_DYNAMIC_MINOR,
>> > +   .minor  = VHCI_MINOR,
>> > };
>> >
>> > static int __init vhci_init(void)
>> > @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
>> > MODULE_VERSION(VERSION);
>> > MODULE_LICENSE("GPL");
>> > MODULE_ALIAS("devname:vhci");
>> > +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
>> > diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
>> > index 3737f72..846a317 100644
>> > --- a/include/linux/miscdevice.h
>> > +++ b/include/linux/miscdevice.h
>> > @@ -48,6 +48,7 @@
>> > #define LOOP_CTRL_MINOR             237
>> > #define VHOST_NET_MINOR             238
>> > #define UHID_MINOR          239
>> > +#define VHCI_MINOR         240
>> > #define MISC_DYNAMIC_MINOR  255
>>
>> you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.
>
> I haven't seen that. So, are we out of minors or.. can I use e.g.
> 142, 129 or the ones below 128?
>
> Kay? Greg?

The minors should be able to carry 20 not 7 or 8 bits, the 32 bit
dev_t is split at 12:20.

Kay

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Greg KH]

On Mon, Feb 17, 2014 at 04:01:25PM -0300, Lucas De Marchi wrote:
> [ CC'ing Kay and Greg ]
> 
> On Mon, Feb 17, 2014 at 08:34:32AM -0800, Marcel Holtmann wrote:
> > Hi Lucas,
> > 
> > > Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
> > > driver) added the module alias to hci_vhci module so it's possible to
> > > create the /dev/vhci node. However creating an alias without
> > > specifying the minor doesn't allow us to create the node ahead,
> > > triggerring module auto-load when it's first accessed.
> > > 
> > > Starting with depmod from kmod 16 we started to warn if there's a
> > > devname alias without specifying the major and minor.
> > > 
> > > Let's do the same done for uhid, kvm, fuse and others, specifying a
> > > fixed minor. In systems with systemd as the init the following will
> > > happen: on early boot systemd will call "kmod static-nodes" to read
> > > /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
> > > first accessed these "dead" nodes will trigger the module loading.
> > > 
> > > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> > > ---
> > > drivers/bluetooth/hci_vhci.c | 3 ++-
> > > include/linux/miscdevice.h   | 1 +
> > > 2 files changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> > > index 1ef6990..add1c6a 100644
> > > --- a/drivers/bluetooth/hci_vhci.c
> > > +++ b/drivers/bluetooth/hci_vhci.c
> > > @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
> > > static struct miscdevice vhci_miscdev= {
> > > 	.name	= "vhci",
> > > 	.fops	= &vhci_fops,
> > > -	.minor	= MISC_DYNAMIC_MINOR,
> > > +	.minor	= VHCI_MINOR,
> > > };
> > > 
> > > static int __init vhci_init(void)
> > > @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
> > > MODULE_VERSION(VERSION);
> > > MODULE_LICENSE("GPL");
> > > MODULE_ALIAS("devname:vhci");
> > > +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
> > > diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> > > index 3737f72..846a317 100644
> > > --- a/include/linux/miscdevice.h
> > > +++ b/include/linux/miscdevice.h
> > > @@ -48,6 +48,7 @@
> > > #define LOOP_CTRL_MINOR		237
> > > #define VHOST_NET_MINOR		238
> > > #define UHID_MINOR		239
> > > +#define VHCI_MINOR		240
> > > #define MISC_DYNAMIC_MINOR	255
> > 
> > you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.
> 
> I haven't seen that. So, are we out of minors or.. can I use e.g.
> 142, 129 or the ones below 128?

As Kay said, larger than 255 should be fine, but you should test this,
and also provide a patch for the devices.txt file to ensure you reserve
the minor number properly.  Looks like someone forgot to do that for the
UHID minor number :(

thanks,

greg k-h

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Lucas De Marchi]

On Mon, Feb 17, 2014 at 02:52:09PM -0800, Greg KH wrote:
> On Mon, Feb 17, 2014 at 04:01:25PM -0300, Lucas De Marchi wrote:
> > [ CC'ing Kay and Greg ]
> > 
> > On Mon, Feb 17, 2014 at 08:34:32AM -0800, Marcel Holtmann wrote:
> > > Hi Lucas,
> > > 
> > > > Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
> > > > driver) added the module alias to hci_vhci module so it's possible to
> > > > create the /dev/vhci node. However creating an alias without
> > > > specifying the minor doesn't allow us to create the node ahead,
> > > > triggerring module auto-load when it's first accessed.
> > > > 
> > > > Starting with depmod from kmod 16 we started to warn if there's a
> > > > devname alias without specifying the major and minor.
> > > > 
> > > > Let's do the same done for uhid, kvm, fuse and others, specifying a
> > > > fixed minor. In systems with systemd as the init the following will
> > > > happen: on early boot systemd will call "kmod static-nodes" to read
> > > > /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
> > > > first accessed these "dead" nodes will trigger the module loading.
> > > > 
> > > > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> > > > ---
> > > > drivers/bluetooth/hci_vhci.c | 3 ++-
> > > > include/linux/miscdevice.h   | 1 +
> > > > 2 files changed, 3 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> > > > index 1ef6990..add1c6a 100644
> > > > --- a/drivers/bluetooth/hci_vhci.c
> > > > +++ b/drivers/bluetooth/hci_vhci.c
> > > > @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
> > > > static struct miscdevice vhci_miscdev= {
> > > > 	.name	= "vhci",
> > > > 	.fops	= &vhci_fops,
> > > > -	.minor	= MISC_DYNAMIC_MINOR,
> > > > +	.minor	= VHCI_MINOR,
> > > > };
> > > > 
> > > > static int __init vhci_init(void)
> > > > @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
> > > > MODULE_VERSION(VERSION);
> > > > MODULE_LICENSE("GPL");
> > > > MODULE_ALIAS("devname:vhci");
> > > > +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
> > > > diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> > > > index 3737f72..846a317 100644
> > > > --- a/include/linux/miscdevice.h
> > > > +++ b/include/linux/miscdevice.h
> > > > @@ -48,6 +48,7 @@
> > > > #define LOOP_CTRL_MINOR		237
> > > > #define VHOST_NET_MINOR		238
> > > > #define UHID_MINOR		239
> > > > +#define VHCI_MINOR		240
> > > > #define MISC_DYNAMIC_MINOR	255
> > > 
> > > you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.
> > 
> > I haven't seen that. So, are we out of minors or.. can I use e.g.
> > 142, 129 or the ones below 128?
> 
> As Kay said, larger than 255 should be fine, but you should test this,
> and also provide a patch for the devices.txt file to ensure you reserve
> the minor number properly.  Looks like someone forgot to do that for the
> UHID minor number :(

yep, doing that now.

Do you prefer 256 or that I fill a gap by using e.g. 196?


-- 
Lucas De Marchi

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Lucas De Marchi]

On Mon, Feb 17, 2014 at 07:52:44PM -0300, Lucas De Marchi wrote:
> On Mon, Feb 17, 2014 at 02:52:09PM -0800, Greg KH wrote:
> > On Mon, Feb 17, 2014 at 04:01:25PM -0300, Lucas De Marchi wrote:
> > > [ CC'ing Kay and Greg ]
> > > 
> > > On Mon, Feb 17, 2014 at 08:34:32AM -0800, Marcel Holtmann wrote:
> > > > Hi Lucas,
> > > > 
> > > > > Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
> > > > > driver) added the module alias to hci_vhci module so it's possible to
> > > > > create the /dev/vhci node. However creating an alias without
> > > > > specifying the minor doesn't allow us to create the node ahead,
> > > > > triggerring module auto-load when it's first accessed.
> > > > > 
> > > > > Starting with depmod from kmod 16 we started to warn if there's a
> > > > > devname alias without specifying the major and minor.
> > > > > 
> > > > > Let's do the same done for uhid, kvm, fuse and others, specifying a
> > > > > fixed minor. In systems with systemd as the init the following will
> > > > > happen: on early boot systemd will call "kmod static-nodes" to read
> > > > > /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
> > > > > first accessed these "dead" nodes will trigger the module loading.
> > > > > 
> > > > > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> > > > > ---
> > > > > drivers/bluetooth/hci_vhci.c | 3 ++-
> > > > > include/linux/miscdevice.h   | 1 +
> > > > > 2 files changed, 3 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> > > > > index 1ef6990..add1c6a 100644
> > > > > --- a/drivers/bluetooth/hci_vhci.c
> > > > > +++ b/drivers/bluetooth/hci_vhci.c
> > > > > @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
> > > > > static struct miscdevice vhci_miscdev= {
> > > > > 	.name	= "vhci",
> > > > > 	.fops	= &vhci_fops,
> > > > > -	.minor	= MISC_DYNAMIC_MINOR,
> > > > > +	.minor	= VHCI_MINOR,
> > > > > };
> > > > > 
> > > > > static int __init vhci_init(void)
> > > > > @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
> > > > > MODULE_VERSION(VERSION);
> > > > > MODULE_LICENSE("GPL");
> > > > > MODULE_ALIAS("devname:vhci");
> > > > > +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
> > > > > diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> > > > > index 3737f72..846a317 100644
> > > > > --- a/include/linux/miscdevice.h
> > > > > +++ b/include/linux/miscdevice.h
> > > > > @@ -48,6 +48,7 @@
> > > > > #define LOOP_CTRL_MINOR		237
> > > > > #define VHOST_NET_MINOR		238
> > > > > #define UHID_MINOR		239
> > > > > +#define VHCI_MINOR		240
> > > > > #define MISC_DYNAMIC_MINOR	255
> > > > 
> > > > you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.
> > > 
> > > I haven't seen that. So, are we out of minors or.. can I use e.g.
> > > 142, 129 or the ones below 128?
> > 
> > As Kay said, larger than 255 should be fine, but you should test this,
> > and also provide a patch for the devices.txt file to ensure you reserve
> > the minor number properly.  Looks like someone forgot to do that for the
> > UHID minor number :(
> 
> yep, doing that now.
> 
> Do you prefer 256 or that I fill a gap by using e.g. 196?

oops, I mean 197

-- 
Lucas De Marchi

Re: [PATCH] Bluetooth: allocate static minor for vhci

[Greg KH]

On Mon, Feb 17, 2014 at 07:54:32PM -0300, Lucas De Marchi wrote:
> On Mon, Feb 17, 2014 at 07:52:44PM -0300, Lucas De Marchi wrote:
> > On Mon, Feb 17, 2014 at 02:52:09PM -0800, Greg KH wrote:
> > > On Mon, Feb 17, 2014 at 04:01:25PM -0300, Lucas De Marchi wrote:
> > > > [ CC'ing Kay and Greg ]
> > > > 
> > > > On Mon, Feb 17, 2014 at 08:34:32AM -0800, Marcel Holtmann wrote:
> > > > > Hi Lucas,
> > > > > 
> > > > > > Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI
> > > > > > driver) added the module alias to hci_vhci module so it's possible to
> > > > > > create the /dev/vhci node. However creating an alias without
> > > > > > specifying the minor doesn't allow us to create the node ahead,
> > > > > > triggerring module auto-load when it's first accessed.
> > > > > > 
> > > > > > Starting with depmod from kmod 16 we started to warn if there's a
> > > > > > devname alias without specifying the major and minor.
> > > > > > 
> > > > > > Let's do the same done for uhid, kvm, fuse and others, specifying a
> > > > > > fixed minor. In systems with systemd as the init the following will
> > > > > > happen: on early boot systemd will call "kmod static-nodes" to read
> > > > > > /lib/modules/$(uname -r)/modules.devname and then create the nodes. When
> > > > > > first accessed these "dead" nodes will trigger the module loading.
> > > > > > 
> > > > > > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> > > > > > ---
> > > > > > drivers/bluetooth/hci_vhci.c | 3 ++-
> > > > > > include/linux/miscdevice.h   | 1 +
> > > > > > 2 files changed, 3 insertions(+), 1 deletion(-)
> > > > > > 
> > > > > > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> > > > > > index 1ef6990..add1c6a 100644
> > > > > > --- a/drivers/bluetooth/hci_vhci.c
> > > > > > +++ b/drivers/bluetooth/hci_vhci.c
> > > > > > @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = {
> > > > > > static struct miscdevice vhci_miscdev= {
> > > > > > 	.name	= "vhci",
> > > > > > 	.fops	= &vhci_fops,
> > > > > > -	.minor	= MISC_DYNAMIC_MINOR,
> > > > > > +	.minor	= VHCI_MINOR,
> > > > > > };
> > > > > > 
> > > > > > static int __init vhci_init(void)
> > > > > > @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
> > > > > > MODULE_VERSION(VERSION);
> > > > > > MODULE_LICENSE("GPL");
> > > > > > MODULE_ALIAS("devname:vhci");
> > > > > > +MODULE_ALIAS_MISCDEV(VHCI_MINOR);
> > > > > > diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> > > > > > index 3737f72..846a317 100644
> > > > > > --- a/include/linux/miscdevice.h
> > > > > > +++ b/include/linux/miscdevice.h
> > > > > > @@ -48,6 +48,7 @@
> > > > > > #define LOOP_CTRL_MINOR		237
> > > > > > #define VHOST_NET_MINOR		238
> > > > > > #define UHID_MINOR		239
> > > > > > +#define VHCI_MINOR		240
> > > > > > #define MISC_DYNAMIC_MINOR	255
> > > > > 
> > > > > you have read Documentation/devices.txt where it states that 240-254 is reserved for local use.
> > > > 
> > > > I haven't seen that. So, are we out of minors or.. can I use e.g.
> > > > 142, 129 or the ones below 128?
> > > 
> > > As Kay said, larger than 255 should be fine, but you should test this,
> > > and also provide a patch for the devices.txt file to ensure you reserve
> > > the minor number properly.  Looks like someone forgot to do that for the
> > > UHID minor number :(
> > 
> > yep, doing that now.
> > 
> > Do you prefer 256 or that I fill a gap by using e.g. 196?
> 
> oops, I mean 197

197 is great to use, just make sure that no one else is using it
in-kernel at the moment.  It looks like I need to update the file with
some more #defines to catch up with what is being used at the moment.

thanks,

greg k-h