[Cluster-devel] Re: mmotm 2009-01-14-20-31 uploaded (gfs2)

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

On Fri, 2009-01-16 at 09:35 -0800, Andrew Morton wrote:
> On Fri, 16 Jan 2009 09:06:23 -0800 Randy Dunlap <randy.dunlap@oracle.com> wrote:
> 
> > >>> which is not ideal, but I don't see any easy way to avoid the #ifdef,
> > >>>
> > >> Take a look in fs.h:
> > >>
> > >> #define generic_setlease(a, b, c) ({ -EINVAL; })
> > >>
> > >> If that wasn't a stupid macro, your code would have compiled and ran
> > >> just as intended.
> > >>
> > > There doesn't seem to be an easy answer though. If I #define it to NULL,
> > > that upsets other parts of the code that rely on that macro, and if I
> > > turn it into a inline function which returns -EINVAL, then presumably I
> > > can't take its address for my file_operations.
> > 
> > No, gcc will allow &inline_func and out-of-line it if it is needed (AFAIK;
> > I've seen a few cases of that).
> > 
> 
> yup.  It measn that we'll get a separate private copy of the
> generic_setlease() code in each compilation unit which takes its
> address, but I don't think that would kill us.
> 
> The prevention is of course to put the stub function in a core kernel
> .c file and export it to modules.
> 
Ok, I'll have another look at this and try and cook something up,

Steve.