Re: [SMP lock BUG?] Re: Feedback on preemptible kernel patch
Robert Love (rml@tech9.net)
17 Sep 2001 20:19:28 -0400
On Mon, 2001-09-17 at 18:40, Manfred Spraul wrote:
> > is it legal to kmap_atomic(a,b); kmap_atomic(c,d); kunmap_atomic(a,b);
>
> Yes, that's legal - just think about one kmap_atomic from process
> context, and another one in irq context.
>
> > If so, your patch may need some ounting....
> > Pavel
>
> I hope ctx_sw_off does internal counting, correct?
yes, ctx_sw_off atomically increments a counter and ctx_sw_on
atomic_dec_and_test()s it.
--
Robert M. Love
rml at ufl.edu
rml at tech9.net
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