Messages in this thread | | | Date | Tue, 3 Dec 2002 11:35:23 +0530 (IST) | From | Madhavi <> | Subject | in_irq() |
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Hi
I am using a UP system with CONFIG_SMP=y in .config with linux 2.4.19 kernel.
I have this piece of code:
spin_lock_irqsave(&some_lock, flags); in_irq(); spin_unlock_irqrestore(&some_lock, flags);
I have read somewhere (I think its given in the Unreliable Guide to kernel locking) that in_irq() returns true when the interrupts are blocked. So, I was expecting in_irq() to return true here. But, it is returning 0 here.
I have gone through the code and it seems that the __local_irq_count is getting incremented only in irq_enter(). So, the behavior I am getting seems to be correct.
## Could someone tell me which is the correct behavior of in_irq()?
## I have one more doubt. If I have a thread in which I do spin_lock_irqsave(&some_lock, flags), can I expect the main kernel thread also not to service any interrupts? I am getting replies to ping packets when the thread is doing spin_lock_irqsave(), which means that all hardware interrupts are not blocked. How can I block all hardware interrupts?
Thanks in advance.
regards Madhavi.
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