| RCU_READ_LOCK_HELD(9) - phpMan
RCU_READ_LOCK_HELD(9) Driver Basics RCU_READ_LOCK_HELD(9)
NAME
rcu_read_lock_held - might we be in RCU read-side critical section?
SYNOPSIS
int rcu_read_lock_held(void);
ARGUMENTS
void
no arguments
DESCRIPTION
If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an RCU read-side critical
section. In absence of CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU read-side
critical section unless it can prove otherwise. This is useful for debug checks in
functions that require that they be called within an RCU read-side critical section.
Checks debug_lockdep_rcu_enabled to prevent false positives during boot and while lockdep
is disabled.
Note that rcu_read_lock and the matching rcu_read_unlock must occur in the same context,
for example, it is illegal to invoke rcu_read_unlock in process context if the matching
rcu_read_lock was invoked from within an irq handler.
Note that rcu_read_lock is disallowed if the CPU is either idle or offline from an RCU
perspective, so check for those as well.
COPYRIGHT
Kernel Hackers Manual 4.8. January 2017 RCU_READ_LOCK_HELD(9)
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