Messages in this thread Patch in this message | | | Date | Tue, 19 Dec 2023 16:18:14 -0800 | Subject | [PATCH v7 03/23] locking/mutex: Make mutex::wait_lock irq safe | From | John Stultz <> |
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From: Juri Lelli <juri.lelli@redhat.com>
mutex::wait_lock might be nested under rq->lock.
Make it irq safe then.
Cc: Joel Fernandes <joelaf@google.com> Cc: Qais Yousef <qyousef@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Zimuzo Ezeozue <zezeozue@google.com> Cc: Youssef Esmat <youssefesmat@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Metin Kaya <Metin.Kaya@arm.com> Cc: Xuewen Yan <xuewen.yan94@gmail.com> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-team@android.com Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [rebase & fix {un,}lock_wait_lock helpers in ww_mutex.h] Signed-off-by: Connor O'Brien <connoro@google.com> Signed-off-by: John Stultz <jstultz@google.com> --- v3: * Re-added this patch after it was dropped in v2 which caused lockdep warnings to trip. v7: * Fix function definition for PREEMPT_RT case, as pointed out by Metin Kaya. * Fix incorrect flags handling in PREEMPT_RT case as found by Metin Kaya --- kernel/locking/mutex.c | 18 ++++++++++-------- kernel/locking/ww_mutex.h | 22 +++++++++++----------- 2 files changed, 21 insertions(+), 19 deletions(-)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 8337ed0dbf81..73d98dd23eec 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -573,6 +573,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas DEFINE_WAKE_Q(wake_q); struct mutex_waiter waiter; struct ww_mutex *ww; + unsigned long flags; int ret; if (!use_ww_ctx) @@ -615,7 +616,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas return 0; } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); /* * After waiting to acquire the wait_lock, try again. */ @@ -676,7 +677,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err; } - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); /* Make sure we do wakeups before calling schedule */ if (!wake_q_empty(&wake_q)) { wake_up_q(&wake_q); @@ -702,9 +703,9 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas trace_contention_begin(lock, LCB_F_MUTEX); } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); acquired: __set_current_state(TASK_RUNNING); @@ -730,7 +731,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas if (ww_ctx) ww_mutex_lock_acquired(ww, ww_ctx); - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); wake_up_q(&wake_q); preempt_enable(); return 0; @@ -740,7 +741,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas __mutex_remove_waiter(lock, &waiter); err_early_kill: trace_contention_end(lock, ret); - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); debug_mutex_free_waiter(&waiter); mutex_release(&lock->dep_map, ip); wake_up_q(&wake_q); @@ -911,6 +912,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne struct task_struct *next = NULL; DEFINE_WAKE_Q(wake_q); unsigned long owner; + unsigned long flags; mutex_release(&lock->dep_map, ip); @@ -938,7 +940,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne } preempt_disable(); - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); debug_mutex_unlock(lock); if (!list_empty(&lock->wait_list)) { /* get the first entry from the wait-list: */ @@ -955,7 +957,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne if (owner & MUTEX_FLAG_HANDOFF) __mutex_handoff(lock, next); - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); wake_up_q(&wake_q); preempt_enable(); } diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h index 7189c6631d90..9facc0ddfdd3 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) @@ -380,6 +380,7 @@ 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); @@ -408,10 +409,9 @@ 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); + lock_wait_lock(&lock->base, &flags); __ww_mutex_check_waiters(&lock->base, ctx, &wake_q); - unlock_wait_lock(&lock->base); - + unlock_wait_lock(&lock->base, &flags); wake_up_q(&wake_q); } -- 2.43.0.472.g3155946c3a-goog
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