Re: [PATCH 1/4] mm: introduce vma_set_file function v2

[Christian König]

Am 08.10.20 um 13:39 schrieb Matthew Wilcox:
> On Thu, Oct 08, 2020 at 01:23:39PM +0200, Christian König wrote:
> >   drivers/dma-buf/dma-buf.c                  | 16 +++++-----------
> >   drivers/gpu/drm/etnaviv/etnaviv_gem.c      |  4 +---
> >   drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c |  3 +--
> >   drivers/gpu/drm/i915/gem/i915_gem_mman.c   |  4 ++--
> >   drivers/gpu/drm/msm/msm_gem.c              |  4 +---
> >   drivers/gpu/drm/omapdrm/omap_gem.c         |  3 +--
> >   drivers/gpu/drm/vgem/vgem_drv.c            |  3 +--
> >   drivers/staging/android/ashmem.c           |  5 ++---
> ...
> > +++ b/mm/mmap.c
> > @@ -136,6 +136,22 @@ void vma_set_page_prot(struct vm_area_struct *vma)
> >   	WRITE_ONCE(vma->vm_page_prot, vm_page_prot);
> >   }
> >   
> > +/*
> > + * Change backing file, only valid to use during initial VMA setup.
> > + */
> > +struct file *vma_set_file(struct vm_area_struct *vma, struct file *file)
> > +{
> > +	if (file)
> > +	        get_file(file);
> > +
> > +	swap(vma->vm_file, file);
> > +
> > +	if (file)
> > +		fput(file);
> > +
> > +	return file;
> > +}
> > +
> These users are all potentially modules.  You need an EXPORT_SYMBOL()?

Oh, good point. Yeah I totally missed that. The initial DMA-buf use case 
was not inside a module.

Thanks,
Christian.