[patch V4 37/68] locking/mutex: Make mutex::wait_lock raw

Thomas Gleixner
2021-08-11T12:26:45Z

The wait_lock of mutex is really a low level lock. Convert it to a
raw_spinlock like the wait_lock of rtmutex.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/mutex.h | 4 ++--
kernel/locking/mutex.c | 22 +++++++++++-----------
2 files changed, 13 insertions(+), 13 deletions(-)
---
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -50,7 +50,7 @@
*/
struct mutex {
atomic_long_t owner;
- spinlock_t wait_lock;
+ raw_spinlock_t wait_lock;
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
struct optimistic_spin_queue osq; /* Spinner MCS lock */
#endif
@@ -105,7 +105,7 @@ do { \

#define __MUTEX_INITIALIZER(lockname) \
{ .owner = ATOMIC_LONG_INIT(0) \
- , .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
+ , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
, .wait_list = LIST_HEAD_INIT(lockname.wait_list) \
__DEBUG_MUTEX_INITIALIZER(lockname) \
__DEP_MAP_MUTEX_INITIALIZER(lockname) }
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -36,7 +36,7 @@ void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
atomic_long_set(&lock->owner, 0);
- spin_lock_init(&lock->wait_lock);
+ raw_spin_lock_init(&lock->wait_lock);
INIT_LIST_HEAD(&lock->wait_list);
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
osq_lock_init(&lock->osq);
@@ -487,9 +487,9 @@ ww_mutex_set_context_fastpath(struct ww_
* Uh oh, we raced in fastpath, check if any of the waiters need to
* die or wound us.
*/
- spin_lock(&lock->base.wait_lock);
+ raw_spin_lock(&lock->base.wait_lock);
__ww_mutex_check_waiters(&lock->base, ctx);
- spin_unlock(&lock->base.wait_lock);
+ raw_spin_unlock(&lock->base.wait_lock);
}

#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
@@ -964,7 +964,7 @@ static __always_inline int __sched
return 0;
}

- spin_lock(&lock->wait_lock);
+ raw_spin_lock(&lock->wait_lock);
/*
* After waiting to acquire the wait_lock, try again.
*/
@@ -1028,7 +1028,7 @@ static __always_inline int __sched
goto err;
}

- spin_unlock(&lock->wait_lock);
+ raw_spin_unlock(&lock->wait_lock);
schedule_preempt_disabled();

/*
@@ -1051,9 +1051,9 @@ static __always_inline int __sched
(first && mutex_optimistic_spin(lock, ww_ctx, &waiter)))
break;

- spin_lock(&lock->wait_lock);
+ raw_spin_lock(&lock->wait_lock);
}
- spin_lock(&lock->wait_lock);
+ raw_spin_lock(&lock->wait_lock);
acquired:
__set_current_state(TASK_RUNNING);

@@ -1078,7 +1078,7 @@ static __always_inline int __sched
if (ww_ctx)
ww_mutex_lock_acquired(ww, ww_ctx);

- spin_unlock(&lock->wait_lock);
+ raw_spin_unlock(&lock->wait_lock);
preempt_enable();
return 0;

@@ -1086,7 +1086,7 @@ static __always_inline int __sched
__set_current_state(TASK_RUNNING);
__mutex_remove_waiter(lock, &waiter);
err_early_kill:
- spin_unlock(&lock->wait_lock);
+ raw_spin_unlock(&lock->wait_lock);
debug_mutex_free_waiter(&waiter);
mutex_release(&lock->dep_map, ip);
preempt_enable();
@@ -1255,7 +1255,7 @@ static noinline void __sched __mutex_unl
owner = old;
}

- spin_lock(&lock->wait_lock);
+ raw_spin_lock(&lock->wait_lock);
debug_mutex_unlock(lock);
if (!list_empty(&lock->wait_list)) {
/* get the first entry from the wait-list: */
@@ -1272,7 +1272,7 @@ static noinline void __sched __mutex_unl
if (owner & MUTEX_FLAG_HANDOFF)
__mutex_handoff(lock, next);

- spin_unlock(&lock->wait_lock);
+ raw_spin_unlock(&lock->wait_lock);

wake_up_q(&wake_q);
}