rcu: Check for have_rcu_nocb_mask instead of rcu_nocb_mask (22c2f669) · Commits · 戴 / test

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>

kernel/rcu/tree_plugin.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -2578,7 +2578,7 @@ static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp)
		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 @@ static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp)
		/* 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;
		}

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