@@ -140,6 +140,7 @@ static void init_srcu_struct_data(struct srcu_struct *ssp)
sdp->srcu_cblist_invoking = false;
sdp->srcu_gp_seq_needed = ssp->srcu_sup->srcu_gp_seq;
sdp->srcu_gp_seq_needed_exp = ssp->srcu_sup->srcu_gp_seq;
+ sdp->srcu_barrier_head.next = &sdp->srcu_barrier_head;
sdp->mynode = NULL;
sdp->cpu = cpu;
INIT_WORK(&sdp->work, srcu_invoke_callbacks);
@@ -1565,6 +1566,7 @@ static void srcu_barrier_cb(struct rcu_head *rhp)
struct srcu_data *sdp;
struct srcu_struct *ssp;
+ rhp->next = rhp; // Mark the callback as having been invoked.
sdp = container_of(rhp, struct srcu_data, srcu_barrier_head);
ssp = sdp->ssp;
if (atomic_dec_and_test(&ssp->srcu_sup->srcu_barrier_cpu_cnt))
SRCU keeps a count of the number of callbacks that the current srcu_barrier() is waiting on, but there is currently no easy way to work out which callback is stuck. One way to do this is to mark idle SRCU-barrier callbacks by making the ->next pointer point to the callback itself, and this commit does just that. Later commits will use this for debug output. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- kernel/rcu/srcutree.c | 2 ++ 1 file changed, 2 insertions(+)