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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-09-20 00:36:42 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-10-19 21:13:36 +0200 |
| commit | 02a7c234e54052101164368ff981bd72f7acdd65 (patch) | |
| tree | 5819d6d63e9f824a702a4b8e90e87720c2b0fe45 /kernel/rcu | |
| parent | rcu: Do not include rtmutex_common.h unconditionally (diff) | |
| download | linux-02a7c234e54052101164368ff981bd72f7acdd65.tar.xz linux-02a7c234e54052101164368ff981bd72f7acdd65.zip | |
rcu: Suppress lockdep false-positive ->boost_mtx complaints
RCU priority boosting uses rt_mutex_init_proxy_locked() to initialize an
rt_mutex structure in locked state held by some other task. When that
other task releases it, lockdep complains (quite accurately, but a bit
uselessly) that the other task never acquired it. This complaint can
suppress other, more helpful, lockdep complaints, and in any case it is
a false positive.
This commit therefore switches from rt_mutex_unlock() to
rt_mutex_futex_unlock(), thereby avoiding the lockdep annotations.
Of course, if lockdep ever learns about rt_mutex_init_proxy_locked(),
addtional adjustments will be required.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 969eae45f05d..1eaab96d1a3c 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -531,7 +531,7 @@ void rcu_read_unlock_special(struct task_struct *t) /* Unboost if we were boosted. */ if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex) - rt_mutex_unlock(&rnp->boost_mtx); + rt_mutex_futex_unlock(&rnp->boost_mtx); /* * If this was the last task on the expedited lists, |