Re: question about nommu.c

[Julia Lawall <julia@diku.dk>]

On Fri, 14 Aug 2009, Paul Mundt wrote:

> On Thu, Aug 13, 2009 at 09:41:38PM +0200, Julia Lawall wrote:
> > The function vmalloc_user in the file mm/nommu.c contains the following 
> > code:
> > 
> > struct vm_area_struct *vma;
> > ...
> > if (vma)
> >         vma->vm_flags |= VM_USERMAP;
> > 
> > The constant VM_USERMAP, however, is elsewhere used in a structure of type 
> > vm_struct, not vm_area_struct.  Furthermore, the value of VM_USERMAP is 8, 
> > which is the same as the value of VM_SHARED (define in mm.h), which is 
> > elsewhere used with a vm_area_struct structure.  Is this occurrence of 
> > VM_USERMAP correct?  Or should it be VM_SHARED?  Or should it be something 
> > else?
> > 
> Yes, this is currently broken, albeit generally harmless. I've been
> working on cleaning this up, but have not gotten around to posting
> patches yet.
> 
> Part of this requires building on top of the infrastructure we have in
> place with the vm_regions to layer a proper vmap implementation on top
> of, which should in turn restore some meaning to the vmlist and permit
> struct vm_struct to be used on nommu properly.
> 
> At the moment this is not a big problem as it doesn't really impact
> anything, it's more regarding future directions for the nommu memory
> management code.

OK, perhaps I should just let you clean it up in a more general way then.

julia

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