Re: "upping" a semaphore from interrupt context?

["Robert P. J. Day" <rpjday@mindspring.com>]

On Sat, 23 Jun 2007, Arnd Bergmann wrote:

> On Saturday 23 June 2007, Robert P. J. Day wrote:
> > On Fri, 22 Jun 2007, Arnd Bergmann wrote:
> > >
> > > yes, but you should not. The use of semaphores is not
> > > recommended for new code, it should be replaced with either a
> > > mutex or a completion.
> >
> > can you clarify this?  it sounds like you're saying that the
> > current implementation of semaphores is entirely superfluous.  but
> > surely it isn't possible to replace all semaphores with either
> > mutexes or completions, is it?
>
> No, not all of them, but the vast majority. There are multiple
> differences, the most important one being the 'counting' in
> semaphores.

right, that was exactly the feature i was thinking of.  ok, i'm clear
on this now -- while the *majority* of semaphores can be more properly
replaced by mutexes or completions, there will always be a need for a
general-purpose counting semaphore.

rday
-- 
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Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

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