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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. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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