diff options
Diffstat (limited to 'kernel/locking/qrwlock.c')
| -rw-r--r-- | kernel/locking/qrwlock.c | 46 |
1 files changed, 23 insertions, 23 deletions
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c index c7471c3fb798..d2ef312a8611 100644 --- a/kernel/locking/qrwlock.c +++ b/kernel/locking/qrwlock.c @@ -1,16 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Queued read/write locks * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * * (C) Copyright 2013-2014 Hewlett-Packard Development Company, L.P. * * Authors: Waiman Long <waiman.long@hp.com> @@ -21,13 +12,13 @@ #include <linux/percpu.h> #include <linux/hardirq.h> #include <linux/spinlock.h> -#include <asm/qrwlock.h> +#include <trace/events/lock.h> /** - * queued_read_lock_slowpath - acquire read lock of a queue rwlock - * @lock: Pointer to queue rwlock structure + * queued_read_lock_slowpath - acquire read lock of a queued rwlock + * @lock: Pointer to queued rwlock structure */ -void queued_read_lock_slowpath(struct qrwlock *lock) +void __lockfunc queued_read_lock_slowpath(struct qrwlock *lock) { /* * Readers come here when they cannot get the lock without waiting @@ -44,6 +35,8 @@ void queued_read_lock_slowpath(struct qrwlock *lock) } atomic_sub(_QR_BIAS, &lock->cnts); + trace_contention_begin(lock, LCB_F_SPIN | LCB_F_READ); + /* * Put the reader into the wait queue */ @@ -61,32 +54,39 @@ void queued_read_lock_slowpath(struct qrwlock *lock) * Signal the next one in queue to become queue head */ arch_spin_unlock(&lock->wait_lock); + + trace_contention_end(lock, 0); } EXPORT_SYMBOL(queued_read_lock_slowpath); /** - * queued_write_lock_slowpath - acquire write lock of a queue rwlock - * @lock : Pointer to queue rwlock structure + * queued_write_lock_slowpath - acquire write lock of a queued rwlock + * @lock : Pointer to queued rwlock structure */ -void queued_write_lock_slowpath(struct qrwlock *lock) +void __lockfunc queued_write_lock_slowpath(struct qrwlock *lock) { + int cnts; + + trace_contention_begin(lock, LCB_F_SPIN | LCB_F_WRITE); + /* Put the writer into the wait queue */ arch_spin_lock(&lock->wait_lock); /* Try to acquire the lock directly if no reader is present */ - if (!atomic_read(&lock->cnts) && - (atomic_cmpxchg_acquire(&lock->cnts, 0, _QW_LOCKED) == 0)) + if (!(cnts = atomic_read(&lock->cnts)) && + atomic_try_cmpxchg_acquire(&lock->cnts, &cnts, _QW_LOCKED)) goto unlock; /* Set the waiting flag to notify readers that a writer is pending */ - atomic_add(_QW_WAITING, &lock->cnts); + atomic_or(_QW_WAITING, &lock->cnts); /* When no more readers or writers, set the locked flag */ do { - atomic_cond_read_acquire(&lock->cnts, VAL == _QW_WAITING); - } while (atomic_cmpxchg_relaxed(&lock->cnts, _QW_WAITING, - _QW_LOCKED) != _QW_WAITING); + cnts = atomic_cond_read_relaxed(&lock->cnts, VAL == _QW_WAITING); + } while (!atomic_try_cmpxchg_acquire(&lock->cnts, &cnts, _QW_LOCKED)); unlock: arch_spin_unlock(&lock->wait_lock); + + trace_contention_end(lock, 0); } EXPORT_SYMBOL(queued_write_lock_slowpath); |