Messages in this thread | | | Subject | Re: [PATCH 1/3] powerpc: Fixup hard_irq_disable semantics | From | Benjamin Herrenschmidt <> | Date | Thu, 10 May 2007 18:44:22 +1000 |
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On Thu, 2007-05-10 at 09:44 +0200, Geert Uytterhoeven wrote: > On Thu, 10 May 2007, Benjamin Herrenschmidt wrote: > > This patch renames the raw hard_irq_{enable,disable} into > > __hard_irq_{enable,disable} and introduces a higher level > > hard_irq_disable() function that can be used by any code > > to enforce that IRQs are fully disabled, not only lazy > > disabled. > > Why did you rename hard_irq_enable() too? > > Isn't it more logical to have high-level hard_irq_disable() and > hard_irq_enable(), and a special low-level __hard_irq_disable()?
Not really. If you see my subsequent patch, the idea is to introduce a single generic hard_irq_disable() which is meant to be called with irqs already disabled (that is within a local_irq_disable section) to enforce that if the arch does lazy disabling, it gets hard disabled at this point.
If we start adding hard_irq_enable() we end up in a can of worms:
- Do we want all the full set of save/restore etc... ? - What if somebody does hard_enable while we are soft-disabled -and- have been hard disabled because of a pending interrupt ? - What's the point ? :-)
So overall, I want to keep the semantics as simple as they can be. Maybe I can even add some WARN_ON() to make sure we are in a local_irq_disable'd section even in the generic one instead of just a NOP to enfore that.
Cheers, Ben.
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