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authorNeeraj Upadhyay <neeraju@codeaurora.org>2021-08-18 13:34:00 +0530
committerPaul E. McKenney <paulmck@kernel.org>2021-09-13 16:32:46 -0700
commitf0b2b2df5423fb369ac762c77900bc7765496d58 (patch)
tree32e5d09f9bb2e6b621e6585ff370b569ede5e232 /kernel/rcu
parent1eac0075ebeecbf5c972f575ac448a0ea92e4f3a (diff)
downloadlinux-f0b2b2df5423fb369ac762c77900bc7765496d58.tar.bz2
rcu: Fix existing exp request check in sync_sched_exp_online_cleanup()
The sync_sched_exp_online_cleanup() checks to see if RCU needs an expedited quiescent state from the incoming CPU, sending it an IPI if so. Before sending IPI, it checks whether expedited qs need has been already requested for the incoming CPU, by checking rcu_data.cpu_no_qs.b.exp for the current cpu, on which sync_sched_exp_online_cleanup() is running. This works for the case where incoming CPU is same as self. However, for the case where incoming CPU is different from self, expedited request won't get marked, which can potentially delay reporting of expedited quiescent state for the incoming CPU. Fixes: e015a3411220 ("rcu: Avoid self-IPI in sync_sched_exp_online_cleanup()") Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree_exp.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index d9e4f8eb9ae2..f3947c49eee7 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -759,7 +759,7 @@ static void sync_sched_exp_online_cleanup(int cpu)
my_cpu = get_cpu();
/* Quiescent state either not needed or already requested, leave. */
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
- __this_cpu_read(rcu_data.cpu_no_qs.b.exp)) {
+ rdp->cpu_no_qs.b.exp) {
put_cpu();
return;
}