* [PATCH 2/3] dummy: make device count build-time configurable
@ 2016-01-12 11:57 Lubomir Rintel
2016-01-12 18:42 ` Stephen Hemminger
0 siblings, 1 reply; 3+ messages in thread
From: Lubomir Rintel @ 2016-01-12 11:57 UTC (permalink / raw)
To: netdev; +Cc: linux-kernel, David S. Miller, Lubomir Rintel
The devices can be created at run-time for quite some time already and the
load-time device creation collides with attempts to create the device of
the same name:
# rmmod dummy
# ip link add dummy0 type dummy
RTNETLINK answers: File exists
This is pretty much the same situation as was with the block loop devices
which was solved by adding a build-time configuration that the
distributions could use as they deem fit while keeping the default for
compatibility.
Let's do that here as well.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
---
drivers/net/Kconfig | 15 +++++++++++++++
drivers/net/dummy.c | 2 +-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 63535b4..f94af69 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -71,6 +71,21 @@ config DUMMY
To compile this driver as a module, choose M here: the module
will be called dummy.
+config DUMMY_COUNT
+ int "Number of dummy devices to pre-create at init time"
+ depends on DUMMY
+ default 1
+ help
+ Static number of dummy devices to be unconditionally pre-created
+ at init time.
+
+ This default value can be overwritten on the kernel command
+ line or with module-parameter dummy.numdummies.
+
+ The historic default is 1. If a mid-2007 version of iproute2
+ is used (v2.6.23 or later), it can be set to 0, since needed
+ dummy devices can be dynamically allocated via rtnetlink.
+
config EQUALIZER
tristate "EQL (serial line load balancing) support"
---help---
diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
index 69fc840..e4506c9 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -41,7 +41,7 @@
#define DRV_NAME "dummy"
#define DRV_VERSION "1.0"
-static int numdummies = 1;
+static int numdummies = CONFIG_DUMMY_COUNT;
/* fake multicast ability */
static void set_multicast_list(struct net_device *dev)
--
2.5.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 2/3] dummy: make device count build-time configurable
2016-01-12 11:57 [PATCH 2/3] dummy: make device count build-time configurable Lubomir Rintel
@ 2016-01-12 18:42 ` Stephen Hemminger
2016-02-05 15:09 ` Lubomir Rintel
0 siblings, 1 reply; 3+ messages in thread
From: Stephen Hemminger @ 2016-01-12 18:42 UTC (permalink / raw)
To: Lubomir Rintel; +Cc: netdev, linux-kernel, David S. Miller
On Tue, 12 Jan 2016 12:57:33 +0100
Lubomir Rintel <lkundrak@v3.sk> wrote:
> The devices can be created at run-time for quite some time already and the
> load-time device creation collides with attempts to create the device of
> the same name:
>
> # rmmod dummy
> # ip link add dummy0 type dummy
> RTNETLINK answers: File exists
>
> This is pretty much the same situation as was with the block loop devices
> which was solved by adding a build-time configuration that the
> distributions could use as they deem fit while keeping the default for
> compatibility.
>
> Let's do that here as well.
>
> Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
There is already a module parameter for this, so making it a compile
time option adds nothing.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2/3] dummy: make device count build-time configurable
2016-01-12 18:42 ` Stephen Hemminger
@ 2016-02-05 15:09 ` Lubomir Rintel
0 siblings, 0 replies; 3+ messages in thread
From: Lubomir Rintel @ 2016-02-05 15:09 UTC (permalink / raw)
To: Stephen Hemminger; +Cc: netdev, linux-kernel, David S. Miller
Hi Stephen,
On Tue, 2016-01-12 at 10:42 -0800, Stephen Hemminger wrote:
> On Tue, 12 Jan 2016 12:57:33 +0100
> Lubomir Rintel <lkundrak@v3.sk> wrote:
>
> > The devices can be created at run-time for quite some time already
> > and the
> > load-time device creation collides with attempts to create the
> > device of
> > the same name:
> >
> > # rmmod dummy
> > # ip link add dummy0 type dummy
> > RTNETLINK answers: File exists
> >
> > This is pretty much the same situation as was with the block loop
> > devices
> > which was solved by adding a build-time configuration that the
> > distributions could use as they deem fit while keeping the default
> > for
> > compatibility.
> >
> > Let's do that here as well.
> >
> > Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
>
> There is already a module parameter for this, so making it a compile
> time option adds nothing.
This option changes the defaults for the parameter.
When the module gets autoloaded, the user doesn't get a chance to
specify the module parameter and unwanted devices pop in.
Worse even, the automatically created devices are likely to collide
with what the user asked for.
Lubo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-01-12 11:57 [PATCH 2/3] dummy: make device count build-time configurable Lubomir Rintel
2016-01-12 18:42 ` Stephen Hemminger
2016-02-05 15:09 ` Lubomir Rintel
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