Re: freeing a static after one use only?

[Peter T. Breuer]

"A month of sundays ago Alan Cox wrote:"
> [ptb wrote]
> > It's  much larger than the thing it's used to create, so there is no
> > advantage in overwriting it with the result.
> > 
> > (I imagine that some of the lowlevel sound card drivers do this, when
> > they want to load firmware).
> 
> They cheat and load a file. Its ugly its bad and Linus doesnt approve of
> the sound approach.
> 
> You want to sit with most of the driver uninitialised until someone opens
> it and does an ioctl load-microcode, then finish registering the devices

I have experimented with using the gcc constructor extensions. The C
ones, that is, not the asm "do at startup" .ctors stuff.

  init_module() {  ....

    foo = kmalloc(lots...);
    __memcpy(foo,(FOO[]){         // use of constructor expression
                 ...
                 { 3, "holidays" },
                 ...
                 },
              many);
    ...
    use(foo);
    kfree(foo);                   // want to get rid of foo now!!!

and to my surprise this doesn't oops. I thought this would allocate
the temporary structure from the stack? Either it is so, and I am about
to crash (the array is about 10K), or gcc  has made a kmalloc/kfree
call ... or it has allocated the temporary data as a static constant.

That seems likely as I see no change in the footprint of the module
code when loaded. Is only the max size returned by lsmod?

Peter