1. I share a data between a kernel thread and an ISR. ( this is a uniprocessor system). In kernel thread I do spin_lock_irqsaveIt is only true if you are not in a SMP environment (and think of those who have multiprocessors) and also if you are not in a preemptive envirnoment (Linux kernel is preemptive since 2.5). So you should protect your data in the ISR too.
and then unlocking. Where as accessing the data from the ISR I do not use any spin lock coz I know when the ISR is running the kernel thread does not get a chance to run. Am I right ???
2. I want to implement a message quque send and recv routine between two kernel threads. ( here I can not use the standard message quques)
What I do is in recv call I check if there is any message in the queue. If no then I sleep on a wait queue.
While sending a message I always add the message to the queue and and use wake up call on wait queue.
Is my implementation leak proff…..or there are some flaws???
Yes it looks good :)
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