On 13:31, Neil Brown wrote: > > Thanks. Sorry if this is a FAQ, but how can one tell whether a given > > function may be called in interrupt context? Is there a better way > > than recursively checking all its callers? > > I think you just have to 'know'. :-( > Some functions which mustn't be called from interrupts are > 'documented' as such by calling "might_sleep()", but there is no > similar documentation for the reverse. There's exactly one call to might_sleep() in drivers/md/*.c ;) > All ->bi_endio routines are called from interrupts.. or maybe > from softirqs or something similar. I think the important point is > that they are called without a process context, so they cannot sleep > (i.e. no kmalloc unless you use GFP_ATOMIC, no mutex_lock, no > wait_event etc) and should use spin_lock_irqsave or spin_lock_bh > rather than a bare spin_lock. So spin_lock_irqsave() and friends are other indicators that the function in question might be called from interrupts while kmalloc(..., GFP_KERNEL) indicates the converse, i.e. that the function is called with process context. Thanks for the explanation. Andre -- The only person who always got his work done by Friday was Robinson Crusoe
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