diff options
Diffstat (limited to 'kernel/locking/ww_mutex.h')
| -rw-r--r-- | kernel/locking/ww_mutex.h | 73 |
1 files changed, 49 insertions, 24 deletions
diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h index 3ad2cc4823e5..31a785afee6c 100644 --- a/kernel/locking/ww_mutex.h +++ b/kernel/locking/ww_mutex.h @@ -70,14 +70,14 @@ __ww_mutex_has_waiters(struct mutex *lock) return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS; } -static inline void lock_wait_lock(struct mutex *lock) +static inline void lock_wait_lock(struct mutex *lock, unsigned long *flags) { - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, *flags); } -static inline void unlock_wait_lock(struct mutex *lock) +static inline void unlock_wait_lock(struct mutex *lock, unsigned long *flags) { - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, *flags); } static inline void lockdep_assert_wait_lock_held(struct mutex *lock) @@ -144,14 +144,14 @@ __ww_mutex_has_waiters(struct rt_mutex *lock) return rt_mutex_has_waiters(&lock->rtmutex); } -static inline void lock_wait_lock(struct rt_mutex *lock) +static inline void lock_wait_lock(struct rt_mutex *lock, unsigned long *flags) { - raw_spin_lock(&lock->rtmutex.wait_lock); + raw_spin_lock_irqsave(&lock->rtmutex.wait_lock, *flags); } -static inline void unlock_wait_lock(struct rt_mutex *lock) +static inline void unlock_wait_lock(struct rt_mutex *lock, unsigned long *flags) { - raw_spin_unlock(&lock->rtmutex.wait_lock); + raw_spin_unlock_irqrestore(&lock->rtmutex.wait_lock, *flags); } static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock) @@ -237,7 +237,7 @@ __ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b) int a_prio = a->task->prio; int b_prio = b->task->prio; - if (rt_prio(a_prio) || rt_prio(b_prio)) { + if (rt_or_dl_prio(a_prio) || rt_or_dl_prio(b_prio)) { if (a_prio > b_prio) return true; @@ -275,7 +275,7 @@ __ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b) */ static bool __ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter, - struct ww_acquire_ctx *ww_ctx) + struct ww_acquire_ctx *ww_ctx, struct wake_q_head *wake_q) { if (!ww_ctx->is_wait_die) return false; @@ -284,7 +284,13 @@ __ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter, #ifndef WW_RT debug_mutex_wake_waiter(lock, waiter); #endif - wake_up_process(waiter->task); + /* + * When waking up the task to die, be sure to clear the + * blocked_on pointer. Otherwise we can see circular + * blocked_on relationships that can't resolve. + */ + __clear_task_blocked_on(waiter->task, lock); + wake_q_add(wake_q, waiter->task); } return true; @@ -299,7 +305,8 @@ __ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter, */ static bool __ww_mutex_wound(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx, - struct ww_acquire_ctx *hold_ctx) + struct ww_acquire_ctx *hold_ctx, + struct wake_q_head *wake_q) { struct task_struct *owner = __ww_mutex_owner(lock); @@ -330,9 +337,19 @@ static bool __ww_mutex_wound(struct MUTEX *lock, * it's wounded in __ww_mutex_check_kill() or has a * wakeup pending to re-read the wounded state. */ - if (owner != current) - wake_up_process(owner); - + if (owner != current) { + /* + * When waking up the task to wound, be sure to clear the + * blocked_on pointer. Otherwise we can see circular + * blocked_on relationships that can't resolve. + * + * NOTE: We pass NULL here instead of lock, because we + * are waking the mutex owner, who may be currently + * blocked on a different mutex. + */ + __clear_task_blocked_on(owner, NULL); + wake_q_add(wake_q, owner); + } return true; } @@ -352,7 +369,8 @@ static bool __ww_mutex_wound(struct MUTEX *lock, * The current task must not be on the wait list. */ static void -__ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx) +__ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx, + struct wake_q_head *wake_q) { struct MUTEX_WAITER *cur; @@ -364,8 +382,8 @@ __ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx) if (!cur->ww_ctx) continue; - if (__ww_mutex_die(lock, cur, ww_ctx) || - __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx)) + if (__ww_mutex_die(lock, cur, ww_ctx, wake_q) || + __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx, wake_q)) break; } } @@ -377,6 +395,9 @@ __ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx) static __always_inline void ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { + DEFINE_WAKE_Q(wake_q); + unsigned long flags; + ww_mutex_lock_acquired(lock, ctx); /* @@ -404,9 +425,12 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) * Uh oh, we raced in fastpath, check if any of the waiters need to * die or wound us. */ - lock_wait_lock(&lock->base); - __ww_mutex_check_waiters(&lock->base, ctx); - unlock_wait_lock(&lock->base); + lock_wait_lock(&lock->base, &flags); + __ww_mutex_check_waiters(&lock->base, ctx, &wake_q); + preempt_disable(); + unlock_wait_lock(&lock->base, &flags); + wake_up_q(&wake_q); + preempt_enable(); } static __always_inline int @@ -488,7 +512,8 @@ __ww_mutex_check_kill(struct MUTEX *lock, struct MUTEX_WAITER *waiter, static inline int __ww_mutex_add_waiter(struct MUTEX_WAITER *waiter, struct MUTEX *lock, - struct ww_acquire_ctx *ww_ctx) + struct ww_acquire_ctx *ww_ctx, + struct wake_q_head *wake_q) { struct MUTEX_WAITER *cur, *pos = NULL; bool is_wait_die; @@ -532,7 +557,7 @@ __ww_mutex_add_waiter(struct MUTEX_WAITER *waiter, pos = cur; /* Wait-Die: ensure younger waiters die. */ - __ww_mutex_die(lock, cur, ww_ctx); + __ww_mutex_die(lock, cur, ww_ctx, wake_q); } __ww_waiter_add(lock, waiter, pos); @@ -550,7 +575,7 @@ __ww_mutex_add_waiter(struct MUTEX_WAITER *waiter, * such that either we or the fastpath will wound @ww->ctx. */ smp_mb(); - __ww_mutex_wound(lock, ww_ctx, ww->ctx); + __ww_mutex_wound(lock, ww_ctx, ww->ctx, wake_q); } return 0; |