diff options
| -rw-r--r-- | kernel/locking/mutex.c | 47 |
1 files changed, 22 insertions, 25 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 49cce442f3ff..59cd6c30421e 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -217,44 +217,41 @@ ww_mutex_set_context_slowpath(struct ww_mutex *lock, } #ifdef CONFIG_MUTEX_SPIN_ON_OWNER -static inline bool owner_running(struct mutex *lock, struct task_struct *owner) -{ - if (lock->owner != owner) - return false; - - /* - * Ensure we emit the owner->on_cpu, dereference _after_ checking - * lock->owner still matches owner, if that fails, owner might - * point to free()d memory, if it still matches, the rcu_read_lock() - * ensures the memory stays valid. - */ - barrier(); - - return owner->on_cpu; -} - /* * Look out! "owner" is an entirely speculative pointer * access and not reliable. */ static noinline -int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) +bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) { + bool ret; + rcu_read_lock(); - while (owner_running(lock, owner)) { - if (need_resched()) + while (true) { + /* Return success when the lock owner changed */ + if (lock->owner != owner) { + ret = true; break; + } + + /* + * Ensure we emit the owner->on_cpu, dereference _after_ + * checking lock->owner still matches owner, if that fails, + * owner might point to free()d memory, if it still matches, + * the rcu_read_lock() ensures the memory stays valid. + */ + barrier(); + + if (!owner->on_cpu || need_resched()) { + ret = false; + break; + } cpu_relax_lowlatency(); } rcu_read_unlock(); - /* - * We break out of the loop above on either need_resched(), when - * the owner is not running, or when the lock owner changed. - * Return success only when the lock owner changed. - */ - return lock->owner != owner; + return ret; } /* |