Re: [PATCH v4 4/5] cramfs: add mmap support

[Nicolas Pitre]

On Tue, 3 Oct 2017, Christoph Hellwig wrote:

> On Tue, Oct 03, 2017 at 11:30:50AM -0400, Nicolas Pitre wrote:
> > Unless you have a better scheme altogether  to suggest of course, given 
> > the existing constraints.
> 
> I still can't understand why this convoluted fault path that finds
> vma, attempts with all kinds of races and then tries to update things
> like vm_ops is even nessecary.
> 
> We have direct mappings of physical address perfectly working in the
> DAX code (even with write support!) or in drivers using remap_pfn_range
> so a really good explanation why neither scheme can be used is needed
> first.

I provided that explanation several times by now in my cover letter. And 
separately even to you directly at least once.  What else should I do?


Nicolas