Re: atomic copy_from_user?

[Andrew Morton]

Joe Korty <joe.korty@xxxxxxxx> wrote:
>
> > inc_preempt_count() and dec_preempt_count() are for use when you
> > _absolutely_ must manage the preemption counter, regardless of whether
> > or not kernel preemption is enabled.
> > 
> > They are used for things like atomic kmaps.
> 
> Hi Robert,
>  I do not see why a non-preempt kernel would care at all about
> the value of preempt_count.  (kmap_atomic is obviously setting it,
> where is the place in a non-preempt kernel where the set value
> is being acted upon?).

do_page_fault()'s in_atomic() test.
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