On Fri, 14 Mar 2008, Davide Madrisan wrote:
> 2008/3/14, Vijay Chauhan <kernel.vijay@xxxxxxxxx>:
> > Hi List,
> >
> > I am a newbie and learning how to write a kernel module.
> > I was reading about __init qualifier, in the init.h file it is mentioned that:
> >
> > I did not understand the purpose of __initdata qualifier?
>
> The tag __initdata is for data used only during initialization (the
> data is put in a special ELF section that is discarded after
> initialization).
>
> > 1. Will the variable be free up after the initialization? Then it is
> > of no use to write the code like:
> > static int init_variable __initdata = 0;
> > Why I will initialize a variable and then free it?
>
> For example to set variables while modprobing the kernel module:
>
> static __initdata char *prm = "userval";
> ...
> module_param(prm, charp, S_IRUGO);
are you sure about the above? can you point at a sample source file
somewhere in the kernel tree that allows __initdata to be applied to
module parameters? i've just never seen that. maybe i haven't looked
hard enough.
rday
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
Have classroom, will lecture.
http://crashcourse.ca Waterloo, Ontario, CANADA
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