[lug] pte_offset in a device driver isn't being found

[D. Stimits]

Michael J. Hammel wrote:

> I'm trying to compile a driver that is using pte_offset().  Linux Device
> Drivers says that include asm/page.h and asm/pgtable.h for this.  I've
> added these (they were missing) but I still get "implicit declaration of
> function pte_offset" when I compile.  The object compiles okay, but I
> want to clean this last warning up before trying the driver out.
>
> I'm including /usr/include and /usr/src/linux-/include in the
> header search path.  I don't think that's the problem - it seems more
> like some defined value isn't getting set to make this function
> prototype visible in the header, though a glance through both page.h and
> pgtable.h doesn't show what that value might be.
>
> Any one have any ideas why I might be getting this?  Jon Corbet - you
> around?


Doing a grep in my 2.4.19 kernel I see it defined as a macro in the 
kernel source tree, /usr/src/linux-2.4/include/asm/pgtable.h. I see the 
same #define in /usr/include/asm/pgtable.h. My guess would be that you 
still get this warning if the #include <asm/pgtable.h> does not occur 
prior to the first use, so make sure it is #include'd within the 
complaining file prior to the line that claims the need (which might 
need other #include's to be after this #include). I didn't check out all 
of the condition #ifdef type declarations in the header, so maybe some 
other definition (or lack of) is going to cause it to fail.

D. Stimits, stimits AT attbi DOT com