global data via module howto
rik at inse.ru
Mon Aug 21 11:00:50 UTC 2006
M. Warner Losh wrote:
> In message: <44E87CCD.30105 at inse.ru>
> Roman Kurakin <rik at inse.ru> writes:
> : I have the following problem:
> : module A
> : int x;
> : module B
> : extern int x;
> : Module A is loaded, module B can't be loaded cause of unknow 'x'.
> : What should I do to make x global?
> Better to make module B depend on module A. Making it global is
> generally a bad idea.
> in module A:
> MODULE_VERSION(A, 1);
> In module B:
> MODULE_DEPEND(B, A, 1, 1, 1);
Module dependence is not the goal.
> : PS. I am working on porting irda support for USB devices from NetBSD.
> : The current model consists of two layers hw and sw. hw is the usb device
> : driver. sw is some software layer the same for all device and it is a
> : child on top of hw 'bus'. To make this working I need to add
> : DRIVER_MODULE for each 'bus'. To make sw independent from the
> : bus I need to export _driver and _class structures and put DRIVER_MODULE
> : in 'bus' code instead of 'child'.
> Are you sure that you need to do this? I'm pretty sure that you can
> create a base class irdabus and then derive all the hw modules that
> implement irdabus from than and all the children will automatically
> probe. No need to export the driver/class structures.
I have a bit reversed case. In common case we have a driver for "bus"
consumers. And we have children that declares itself via DRIVER_MODULE.
If child could work on several buses it declares itself several times
one for each
bus. In my case I have several drivers that could be treated as bus
driver for the
| | |
ustir uirda smth_else
\ | /
Imagine, if the network interface was implemented as a child of every
adapter. This is the same. In common case I'll put DRIVER_MODULE in a child
for each bus and recompile after adding a new one. In this case I do no
recompile the child for every new "bus" since child do not depend on
- it is the same for all. So we may call this a pseudo-device with
of buses. I know, I could implement this other way, but I just want to
newbus a bit and the original NetBSD driver was implemented this way.
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