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| author |   Oleg Nesterov <oleg@redhat.com> | 2015-08-21 19:43:03 +0200 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-10-06 11:25:40 -0700 |
| commit | cc5f730b41506d37a5c2826b2e801d0a59853d11 (patch) | |
| tree | 9fdb987ba3a660abc7c71752ec0c5a953268117f /kernel/locking/percpu-rwsem.c | |
| parent | locking/percpu-rwsem: Fix the comments outdated by rcu_sync (diff) | |
| download | linux-dev-cc5f730b41506d37a5c2826b2e801d0a59853d11.tar.xz linux-dev-cc5f730b41506d37a5c2826b2e801d0a59853d11.zip | |
locking/percpu-rwsem: Clean up the lockdep annotations in percpu_down_read()
Based on Peter Zijlstra's earlier patch.
Change percpu_down_read() to use __down_read(), this way we can
do rwsem_acquire_read() unconditionally at the start to make this
code more symmetric and clean.
Originally-From: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/locking/percpu-rwsem.c')
| -rw-r--r-- | kernel/locking/percpu-rwsem.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index 02a726dd9adc..f231e0bb311c 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -70,14 +70,14 @@ static bool update_fast_ctr(struct percpu_rw_semaphore *brw, unsigned int val) void percpu_down_read(struct percpu_rw_semaphore *brw) { might_sleep(); - if (likely(update_fast_ctr(brw, +1))) { - rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 0, _RET_IP_); + rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 0, _RET_IP_); + + if (likely(update_fast_ctr(brw, +1))) return; - } - down_read(&brw->rw_sem); + /* Avoid rwsem_acquire_read() and rwsem_release() */ + __down_read(&brw->rw_sem); atomic_inc(&brw->slow_read_ctr); - /* avoid up_read()->rwsem_release() */ __up_read(&brw->rw_sem); } EXPORT_SYMBOL_GPL(percpu_down_read); |