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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-12-20 07:17:58 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-01-23 11:37:13 -0800 |
| commit | fdbb9b315ce40922f3a8d2b8352776d7bc963d84 (patch) | |
| tree | 47e1d70175d586c4c0d35e79f9aa6b6ce11615b7 /kernel/rcu | |
| parent | 09e2db37ec6d22bc27e2ba94ab4889541567f52e (diff) | |
| download | op-kernel-dev-fdbb9b315ce40922f3a8d2b8352776d7bc963d84.zip op-kernel-dev-fdbb9b315ce40922f3a8d2b8352776d7bc963d84.tar.gz | |
rcu: Make rcu_cpu_starting() use its "cpu" argument
The rcu_cpu_starting() function uses this_cpu_ptr() to locate the
incoming CPU's rcu_data structure. This works for the boot CPU and for
all CPUs onlined after rcu_init() executes (during very early boot).
Currently, this is the full set of CPUs, so all is well. But if
anyone ever parallelizes boot before rcu_init() time, it will fail.
This commit therefore substitutes the rcu_cpu_starting() function's
this_cpu_pointer() for per_cpu_ptr(), future-proofing the code and
(arguably) improving readability.
This commit inadvertently fixes a latent bug: If there ever had been
more than just the boot CPU online at rcu_init() time, the old code
would not initialize the non-boot CPUs, but rather would repeatedly
initialize the boot CPU.
Reported-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index be23012..a4b4762 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3873,7 +3873,7 @@ void rcu_cpu_starting(unsigned int cpu) struct rcu_state *rsp; for_each_rcu_flavor(rsp) { - rdp = this_cpu_ptr(rsp->rda); + rdp = per_cpu_ptr(rsp->rda, cpu); rnp = rdp->mynode; mask = rdp->grpmask; raw_spin_lock_irqsave_rcu_node(rnp, flags); |
