See include/linux/hardirq.h
in_irq() returns true when in interrupt handler;
in_softirq() returns true when in bottom-half (softirq,tasklet)
in_interrupt() returns true when in interrupt handler or bottom-half
#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
/*
* Are we doing bottom half or hardware interrupt processing?
* Are we in a softirq context? Interrupt context?
*/
#define in_irq() (hardirq_count())
#define in_softirq() (softirq_count())
#define in_interrupt() (irq_count())
Hope, it helps.
Bruce Moffat 写道:
Hi,
I am looking for a way to test whether I am running in a bottom half
context or user context. There are kernel functions which may be
called from both user and bottom half contex. For eg,
tcp_transmit_skb, may be called from user context for first time
transmission of a packet or from the timer bottom half in case of
retransmission. Is there a way to check within that function whether
it is currently running in user / bottom half context?
Any hints greatly appreciated !
Regards,
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