Messages in this thread Patch in this message | | | From | Pranith Kumar <> | Date | Wed, 23 Jul 2014 13:14:19 -0400 | Subject | Re: [PATCH 02/16] rcu: Check return value for cpumask allocation |
| |
On Wed, Jul 23, 2014 at 8:06 AM, Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote: >> --- a/kernel/rcu/tree_plugin.h >> +++ b/kernel/rcu/tree_plugin.h >> @@ -88,7 +88,10 @@ static void __init rcu_bootup_announce_oddness(void) >> #ifdef CONFIG_RCU_NOCB_CPU >> #ifndef CONFIG_RCU_NOCB_CPU_NONE >> if (!have_rcu_nocb_mask) { >> - zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL); >> + if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) { >> + pr_info("rcu_nocb_mask allocation failed\n"); >> + return; > > Good catch, but this "return" is an accident waiting to happen. The > accident will happen as soon as another RCU option appears, and the > person adding it quite naturally adds it at the end of this function. > The cleanest approach is to make an rcu_bootup_announce_oddness_nocb() > as one commit that does -only- code motion, and the make this change > as another commit. >
Hi Paul,
Looking at this, I think the following is simpler without having to introduce a new function. What do you think?
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index c31eb28..f2ed342 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -88,8 +88,10 @@ static void __init rcu_bootup_announce_oddness(void) #ifdef CONFIG_RCU_NOCB_CPU #ifndef CONFIG_RCU_NOCB_CPU_NONE if (!have_rcu_nocb_mask) { - zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL); - have_rcu_nocb_mask = true; + if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) + pr_info("rcu_nocb_mask allocation failed"); + else + have_rcu_nocb_mask = true; } #ifdef CONFIG_RCU_NOCB_CPU_ZERO pr_info("\tOffload RCU callbacks from CPU 0\n");
-- Pranith
| |