From: Kunwu Chan <[email protected]> Atomic SRCU must remain in the small size state. Warn if this invariant is violated and avoid transitioning to big in that case.
[ paulmck: Folded "if" onto one line for 100-character limit. ] Signed-off-by: Kunwu Chan <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Reviewed-by: Bradley Morgan <[email protected]> --- kernel/rcu/srcutree.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 4e9a0b8ea344..6a05bd8a6f39 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1073,8 +1073,10 @@ static void srcu_gp_end(struct srcu_struct *ssp, bool is_atomic) raw_spin_unlock_irq_rcu_node(sup); } - /* Transition to big if needed. */ - if (ss_state != SRCU_SIZE_SMALL && ss_state != SRCU_SIZE_BIG) { + /* Transition to big if needed, but never for atomic SRCU. */ + if (ssp->srcu_reader_flavor == SRCU_READ_FLAVOR_ATOMIC && ss_state != SRCU_SIZE_SMALL) { + WARN_ON_ONCE(1); + } else if (ss_state != SRCU_SIZE_SMALL && ss_state != SRCU_SIZE_BIG) { if (ss_state == SRCU_SIZE_ALLOC) init_srcu_struct_nodes(ssp, GFP_KERNEL); else -- 2.40.1
