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Subject[PATCH 04/10] locking/qspinlock: Use atomic_cond_read_acquire
Date
Rather than dig into the counter field of the atomic_t inside the
qspinlock structure so that we can call smp_cond_load_acquire, use
atomic_cond_read_acquire instead, which operates on the atomic_t
directly.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
kernel/locking/qspinlock.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
index cdfa7b7328a8..291e1526d27b 100644
--- a/kernel/locking/qspinlock.c
+++ b/kernel/locking/qspinlock.c
@@ -331,8 +331,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
* barriers.
*/
if (val & _Q_LOCKED_MASK)
- smp_cond_load_acquire(&lock->val.counter,
- !(VAL & _Q_LOCKED_MASK));
+ atomic_cond_read_acquire(&lock->val,
+ !(VAL & _Q_LOCKED_MASK));
/*
* take ownership and clear the pending bit.
*
@@ -433,8 +433,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
*
* The PV pv_wait_head_or_lock function, if active, will acquire
* the lock and return a non-zero value. So we have to skip the
- * smp_cond_load_acquire() call. As the next PV queue head hasn't been
- * designated yet, there is no way for the locked value to become
+ * atomic_cond_read_acquire() call. As the next PV queue head hasn't
+ * been designated yet, there is no way for the locked value to become
* _Q_SLOW_VAL. So both the set_locked() and the
* atomic_cmpxchg_relaxed() calls will be safe.
*
@@ -444,7 +444,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
if ((val = pv_wait_head_or_lock(lock, node)))
goto locked;

- val = smp_cond_load_acquire(&lock->val.counter, !(VAL & _Q_LOCKED_PENDING_MASK));
+ val = atomic_cond_read_acquire(&lock->val, !(VAL & _Q_LOCKED_PENDING_MASK));

locked:
/*
@@ -461,7 +461,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
/* In the PV case we might already have _Q_LOCKED_VAL set */
if ((val & _Q_TAIL_MASK) == tail) {
/*
- * The smp_cond_load_acquire() call above has provided the
+ * The atomic_cond_read_acquire() call above has provided the
* necessary acquire semantics required for locking.
*/
old = atomic_cmpxchg_relaxed(&lock->val, val, _Q_LOCKED_VAL);
--
2.1.4
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