• Paul E. McKenney's avatar
    rcu: Provide functions for determining if call_rcu() has been invoked · 74de6960
    Paul E. McKenney authored
    This commit adds rcu_head_init() and rcu_head_after_call_rcu() functions
    to help RCU users detect when another CPU has passed the specified
    rcu_head structure and function to call_rcu().  The rcu_head_init()
    should be invoked before making the structure visible to RCU readers,
    and then the rcu_head_after_call_rcu() may be invoked from within
    an RCU read-side critical section on an rcu_head structure that
    was obtained during a traversal of the data structure in question.
    The rcu_head_after_call_rcu() function will return true if the rcu_head
    structure has already been passed (with the specified function) to
    call_rcu(), otherwise it will return false.
    If rcu_head_init() has not been invoked on the rcu_head structure
    or if the rcu_head (AKA callback) has already been invoked, then
    rcu_head_after_call_rcu() will do WARN_ON_ONCE().
    Reported-by: default avatarNeilBrown <neilb@suse.com>
    Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    [ paulmck: Apply neilb naming feedback. ]
rcupdate.h 33.9 KB