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-rw-r--r--kernel/locking/mcs_spinlock.h4
-rw-r--r--kernel/locking/mutex.c9
-rw-r--r--kernel/locking/osq_lock.c11
-rw-r--r--kernel/locking/qrwlock.c8
-rw-r--r--kernel/locking/qspinlock_paravirt.h6
-rw-r--r--kernel/locking/rtmutex.c30
-rw-r--r--kernel/locking/rwsem-xadd.c5
7 files changed, 44 insertions, 29 deletions
diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h
index fd91aaa4554c..5b9102a47ea5 100644
--- a/kernel/locking/mcs_spinlock.h
+++ b/kernel/locking/mcs_spinlock.h
@@ -67,7 +67,7 @@ void mcs_spin_lock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
node->locked = 0;
node->next = NULL;
- prev = xchg(lock, node);
+ prev = xchg_acquire(lock, node);
if (likely(prev == NULL)) {
/*
* Lock acquired, don't need to set node->locked to 1. Threads
@@ -98,7 +98,7 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
/*
* Release the lock by setting it to NULL
*/
- if (likely(cmpxchg(lock, node, NULL) == node))
+ if (likely(cmpxchg_release(lock, node, NULL) == node))
return;
/* Wait until the next pointer is set */
while (!(next = READ_ONCE(node->next)))
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 4cccea6b8934..0551c219c40e 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -277,7 +277,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
static inline bool mutex_try_to_acquire(struct mutex *lock)
{
return !mutex_is_locked(lock) &&
- (atomic_cmpxchg(&lock->count, 1, 0) == 1);
+ (atomic_cmpxchg_acquire(&lock->count, 1, 0) == 1);
}
/*
@@ -529,7 +529,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* Once more, try to acquire the lock. Only try-lock the mutex if
* it is unlocked to reduce unnecessary xchg() operations.
*/
- if (!mutex_is_locked(lock) && (atomic_xchg(&lock->count, 0) == 1))
+ if (!mutex_is_locked(lock) &&
+ (atomic_xchg_acquire(&lock->count, 0) == 1))
goto skip_wait;
debug_mutex_lock_common(lock, &waiter);
@@ -553,7 +554,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* non-negative in order to avoid unnecessary xchg operations:
*/
if (atomic_read(&lock->count) >= 0 &&
- (atomic_xchg(&lock->count, -1) == 1))
+ (atomic_xchg_acquire(&lock->count, -1) == 1))
break;
/*
@@ -867,7 +868,7 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
spin_lock_mutex(&lock->wait_lock, flags);
- prev = atomic_xchg(&lock->count, -1);
+ prev = atomic_xchg_acquire(&lock->count, -1);
if (likely(prev == 1)) {
mutex_set_owner(lock);
mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index dc85ee23a26f..d092a0c9c2d4 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -50,7 +50,7 @@ osq_wait_next(struct optimistic_spin_queue *lock,
for (;;) {
if (atomic_read(&lock->tail) == curr &&
- atomic_cmpxchg(&lock->tail, curr, old) == curr) {
+ atomic_cmpxchg_acquire(&lock->tail, curr, old) == curr) {
/*
* We were the last queued, we moved @lock back. @prev
* will now observe @lock and will complete its
@@ -92,7 +92,11 @@ bool osq_lock(struct optimistic_spin_queue *lock)
node->next = NULL;
node->cpu = curr;
- old = atomic_xchg(&lock->tail, curr);
+ /*
+ * ACQUIRE semantics, pairs with corresponding RELEASE
+ * in unlock() uncontended, or fastpath.
+ */
+ old = atomic_xchg_acquire(&lock->tail, curr);
if (old == OSQ_UNLOCKED_VAL)
return true;
@@ -184,7 +188,8 @@ void osq_unlock(struct optimistic_spin_queue *lock)
/*
* Fast path for the uncontended case.
*/
- if (likely(atomic_cmpxchg(&lock->tail, curr, OSQ_UNLOCKED_VAL) == curr))
+ if (likely(atomic_cmpxchg_release(&lock->tail, curr,
+ OSQ_UNLOCKED_VAL) == curr))
return;
/*
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c
index f17a3e3b3550..fec082338668 100644
--- a/kernel/locking/qrwlock.c
+++ b/kernel/locking/qrwlock.c
@@ -86,7 +86,7 @@ void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts)
/*
* Put the reader into the wait queue
*/
- arch_spin_lock(&lock->lock);
+ arch_spin_lock(&lock->wait_lock);
/*
* The ACQUIRE semantics of the following spinning code ensure
@@ -99,7 +99,7 @@ void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts)
/*
* Signal the next one in queue to become queue head
*/
- arch_spin_unlock(&lock->lock);
+ arch_spin_unlock(&lock->wait_lock);
}
EXPORT_SYMBOL(queued_read_lock_slowpath);
@@ -112,7 +112,7 @@ void queued_write_lock_slowpath(struct qrwlock *lock)
u32 cnts;
/* Put the writer into the wait queue */
- arch_spin_lock(&lock->lock);
+ arch_spin_lock(&lock->wait_lock);
/* Try to acquire the lock directly if no reader is present */
if (!atomic_read(&lock->cnts) &&
@@ -144,6 +144,6 @@ void queued_write_lock_slowpath(struct qrwlock *lock)
cpu_relax_lowlatency();
}
unlock:
- arch_spin_unlock(&lock->lock);
+ arch_spin_unlock(&lock->wait_lock);
}
EXPORT_SYMBOL(queued_write_lock_slowpath);
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index c8e6e9a596f5..f0450ff4829b 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -267,7 +267,6 @@ static void pv_wait_head(struct qspinlock *lock, struct mcs_spinlock *node)
}
if (!lp) { /* ONCE */
- WRITE_ONCE(pn->state, vcpu_hashed);
lp = pv_hash(lock, pn);
/*
@@ -275,11 +274,9 @@ static void pv_wait_head(struct qspinlock *lock, struct mcs_spinlock *node)
* when we observe _Q_SLOW_VAL in __pv_queued_spin_unlock()
* we'll be sure to be able to observe our hash entry.
*
- * [S] pn->state
* [S] <hash> [Rmw] l->locked == _Q_SLOW_VAL
* MB RMB
* [RmW] l->locked = _Q_SLOW_VAL [L] <unhash>
- * [L] pn->state
*
* Matches the smp_rmb() in __pv_queued_spin_unlock().
*/
@@ -364,8 +361,7 @@ __visible void __pv_queued_spin_unlock(struct qspinlock *lock)
* vCPU is harmless other than the additional latency in completing
* the unlock.
*/
- if (READ_ONCE(node->state) == vcpu_hashed)
- pv_kick(node->cpu);
+ pv_kick(node->cpu);
}
/*
* Include the architecture specific callee-save thunk of the
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 7781d801212f..bbb72b4f64a1 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -74,14 +74,23 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
* set up.
*/
#ifndef CONFIG_DEBUG_RT_MUTEXES
-# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c)
+# define rt_mutex_cmpxchg_relaxed(l,c,n) (cmpxchg_relaxed(&l->owner, c, n) == c)
+# define rt_mutex_cmpxchg_acquire(l,c,n) (cmpxchg_acquire(&l->owner, c, n) == c)
+# define rt_mutex_cmpxchg_release(l,c,n) (cmpxchg_release(&l->owner, c, n) == c)
+
+/*
+ * Callers must hold the ->wait_lock -- which is the whole purpose as we force
+ * all future threads that attempt to [Rmw] the lock to the slowpath. As such
+ * relaxed semantics suffice.
+ */
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
{
unsigned long owner, *p = (unsigned long *) &lock->owner;
do {
owner = *p;
- } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner);
+ } while (cmpxchg_relaxed(p, owner,
+ owner | RT_MUTEX_HAS_WAITERS) != owner);
}
/*
@@ -121,11 +130,14 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock)
* lock(wait_lock);
* acquire(lock);
*/
- return rt_mutex_cmpxchg(lock, owner, NULL);
+ return rt_mutex_cmpxchg_release(lock, owner, NULL);
}
#else
-# define rt_mutex_cmpxchg(l,c,n) (0)
+# define rt_mutex_cmpxchg_relaxed(l,c,n) (0)
+# define rt_mutex_cmpxchg_acquire(l,c,n) (0)
+# define rt_mutex_cmpxchg_release(l,c,n) (0)
+
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
{
lock->owner = (struct task_struct *)
@@ -1321,7 +1333,7 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
enum rtmutex_chainwalk chwalk))
{
- if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) {
rt_mutex_deadlock_account_lock(lock, current);
return 0;
} else
@@ -1337,7 +1349,7 @@ rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
enum rtmutex_chainwalk chwalk))
{
if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
- likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) {
rt_mutex_deadlock_account_lock(lock, current);
return 0;
} else
@@ -1348,7 +1360,7 @@ static inline int
rt_mutex_fasttrylock(struct rt_mutex *lock,
int (*slowfn)(struct rt_mutex *lock))
{
- if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) {
rt_mutex_deadlock_account_lock(lock, current);
return 1;
}
@@ -1362,7 +1374,7 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
{
WAKE_Q(wake_q);
- if (likely(rt_mutex_cmpxchg(lock, current, NULL))) {
+ if (likely(rt_mutex_cmpxchg_release(lock, current, NULL))) {
rt_mutex_deadlock_account_unlock(current);
} else {
@@ -1484,7 +1496,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_unlock);
bool __sched rt_mutex_futex_unlock(struct rt_mutex *lock,
struct wake_q_head *wqh)
{
- if (likely(rt_mutex_cmpxchg(lock, current, NULL))) {
+ if (likely(rt_mutex_cmpxchg_release(lock, current, NULL))) {
rt_mutex_deadlock_account_unlock(current);
return false;
}
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 0f189714e457..a4d4de05b2d1 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -262,7 +262,7 @@ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
* to reduce unnecessary expensive cmpxchg() operations.
*/
if (count == RWSEM_WAITING_BIAS &&
- cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
+ cmpxchg_acquire(&sem->count, RWSEM_WAITING_BIAS,
RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
if (!list_is_singular(&sem->wait_list))
rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
@@ -285,7 +285,8 @@ static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
if (!(count == 0 || count == RWSEM_WAITING_BIAS))
return false;
- old = cmpxchg(&sem->count, count, count + RWSEM_ACTIVE_WRITE_BIAS);
+ old = cmpxchg_acquire(&sem->count, count,
+ count + RWSEM_ACTIVE_WRITE_BIAS);
if (old == count) {
rwsem_set_owner(sem);
return true;
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-21 07:31:20 +0000