Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 22 Dec 2003 16:59:34 -0500 | From | Joe Korty <> | Subject | Re: atomic copy_from_user? |
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On Mon, Dec 22, 2003 at 04:40:11PM -0500, Rob Love wrote: > On Mon, 2003-12-22 at 16:22, Joe Korty wrote: > > > I am guessing that nowdays even when preemption is disabled one can > > find preempt_count still being used somewhere. Otherwise it would be > > better to replace all uses of inc_preempt_count() with > > preempt_disable() and dec_preempt_count() with preempt_enable(). > > Right. So why did you make this patch? :) > > 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?).
Joe
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