rcu: Check for have_rcu_nocb_mask instead of rcu_nocb_mask
If we configure a kernel with CONFIG_NOCB_CPU=y, CONFIG_RCU_NOCB_CPU_NONE=y and
CONFIG_CPUMASK_OFFSTACK=n and do not pass in a rcu_nocb= boot parameter, the
cpumask rcu_nocb_mask can be garbage instead of NULL.
Hence this commit replaces checks for rcu_nocb_mask == NULL with a check for
have_rcu_nocb_mask.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 31c7afb..39e68bc 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2578,7 +2578,7 @@
struct rcu_data *rdp_leader = NULL; /* Suppress misguided gcc warn. */
struct rcu_data *rdp_prev = NULL;
- if (rcu_nocb_mask == NULL)
+ if (!have_rcu_nocb_mask)
return;
if (ls == -1) {
ls = int_sqrt(nr_cpu_ids);
@@ -2608,9 +2608,9 @@
/* Prevent __call_rcu() from enqueuing callbacks on no-CBs CPUs */
static bool init_nocb_callback_list(struct rcu_data *rdp)
{
- if (rcu_nocb_mask == NULL ||
- !cpumask_test_cpu(rdp->cpu, rcu_nocb_mask))
+ if (!rcu_is_nocb_cpu(rdp->cpu))
return false;
+
rdp->nxttail[RCU_NEXT_TAIL] = NULL;
return true;
}