diff options
| author | John Stultz <jstultz@google.com> | 2024-12-16 20:07:35 -0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-12-20 15:31:21 +0100 |
| commit | abfdccd6af2b071951633e57d6322c46a1ea791f (patch) | |
| tree | d852a162cbe01984b07795b714d31e39b6e85450 /kernel/locking/mutex.c | |
| parent | c2db11a750fb626d0d04f2dc76e548a1f07617df (diff) | |
sched/wake_q: Add helper to call wake_up_q after unlock with preemption disabled
A common pattern seen when wake_qs are used to defer a wakeup
until after a lock is released is something like:
preempt_disable();
raw_spin_unlock(lock);
wake_up_q(wake_q);
preempt_enable();
So create some raw_spin_unlock*_wake() helper functions to clean
this up.
Applies on top of the fix I submitted here:
https://lore.kernel.org/lkml/20241212222138.2400498-1-jstultz@google.com/
NOTE: I recognise the unlock()/unlock_irq()/unlock_irqrestore()
variants creates its own duplication, which we could use a macro
to generate the similar functions, but I often dislike how those
generation macros making finding the actual implementation
harder, so I left the three functions as is. If folks would
prefer otherwise, let me know and I'll switch it.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241217040803.243420-1-jstultz@google.com
Diffstat (limited to 'kernel/locking/mutex.c')
| -rw-r--r-- | kernel/locking/mutex.c | 16 |
1 files changed, 4 insertions, 12 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 3302e52f0c96..b36f23de48f1 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -657,10 +657,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err; } - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); - /* Make sure we do wakeups before calling schedule */ - wake_up_q(&wake_q); - wake_q_init(&wake_q); + raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q); schedule_preempt_disabled(); @@ -710,8 +707,7 @@ skip_wait: if (ww_ctx) ww_mutex_lock_acquired(ww, ww_ctx); - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); - wake_up_q(&wake_q); + raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q); preempt_enable(); return 0; @@ -720,10 +716,9 @@ err: __mutex_remove_waiter(lock, &waiter); err_early_kill: trace_contention_end(lock, ret); - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); + raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q); debug_mutex_free_waiter(&waiter); mutex_release(&lock->dep_map, ip); - wake_up_q(&wake_q); preempt_enable(); return ret; } @@ -935,10 +930,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne if (owner & MUTEX_FLAG_HANDOFF) __mutex_handoff(lock, next); - preempt_disable(); - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); - wake_up_q(&wake_q); - preempt_enable(); + raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q); } #ifndef CONFIG_DEBUG_LOCK_ALLOC |