zircon/kernel/include/kernel/auto_lock.h

// Copyright 2016 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#ifndef ZIRCON_KERNEL_INCLUDE_KERNEL_AUTO_LOCK_H_
#define ZIRCON_KERNEL_INCLUDE_KERNEL_AUTO_LOCK_H_

#include <fbl/macros.h>
#include <kernel/mutex.h>
#include <kernel/spinlock.h>

// Various lock guard wrappers for kernel only locks

class TA_SCOPED_CAP AutoSpinLockNoIrqSave {
 public:
  __WARN_UNUSED_CONSTRUCTOR explicit AutoSpinLockNoIrqSave(spin_lock_t* lock) TA_ACQ(lock)
      : spinlock_(lock) {
    DEBUG_ASSERT(lock);
    spin_lock(spinlock_);
  }
  __WARN_UNUSED_CONSTRUCTOR explicit AutoSpinLockNoIrqSave(SpinLock* lock) TA_ACQ(lock)
      : AutoSpinLockNoIrqSave(lock->GetInternal()) {}
  ~AutoSpinLockNoIrqSave() TA_REL() { release(); }

  void release() TA_REL() {
    if (spinlock_) {
      spin_unlock(spinlock_);
      spinlock_ = nullptr;
    }
  }

  // suppress default constructors
  DISALLOW_COPY_ASSIGN_AND_MOVE(AutoSpinLockNoIrqSave);

 private:
  spin_lock_t* spinlock_;
};

class TA_SCOPED_CAP AutoSpinLock {
 public:
  __WARN_UNUSED_CONSTRUCTOR explicit AutoSpinLock(spin_lock_t* lock) TA_ACQ(lock)
      : spinlock_(lock) {
    DEBUG_ASSERT(lock);
    spin_lock_irqsave(spinlock_, state_);
  }
  __WARN_UNUSED_CONSTRUCTOR explicit AutoSpinLock(SpinLock* lock) TA_ACQ(lock)
      : AutoSpinLock(lock->GetInternal()) {}
  ~AutoSpinLock() TA_REL() { release(); }

  void release() TA_REL() {
    if (spinlock_) {
      spin_unlock_irqrestore(spinlock_, state_);
      spinlock_ = nullptr;
    }
  }

  // suppress default constructors
  DISALLOW_COPY_ASSIGN_AND_MOVE(AutoSpinLock);

 private:
  spin_lock_t* spinlock_;
  spin_lock_saved_state_t state_;
};

#endif  // ZIRCON_KERNEL_INCLUDE_KERNEL_AUTO_LOCK_H_