gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sync/locking/generic_mutex.go (about)

     1  // Copyright 2022 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package locking
    16  
    17  import (
    18  	"reflect"
    19  
    20  	"gvisor.dev/gvisor/pkg/sync"
    21  	"gvisor.dev/gvisor/pkg/sync/locking"
    22  )
    23  
    24  // Mutex is sync.Mutex with the correctness validator.
    25  type Mutex struct {
    26  	mu sync.Mutex
    27  }
    28  
    29  var genericMarkIndex *locking.MutexClass
    30  
    31  // lockNames is a list of user-friendly lock names.
    32  // Populated in init.
    33  var lockNames []string
    34  
    35  // lockNameIndex is used as an index passed to NestedLock and NestedUnlock,
    36  // referring to an index within lockNames.
    37  // Values are specified using the "consts" field of go_template_instance.
    38  type lockNameIndex int
    39  
    40  // DO NOT REMOVE: The following function automatically replaced with lock index constants.
    41  // LOCK_NAME_INDEX_CONSTANTS
    42  const ()
    43  
    44  // Lock locks m.
    45  // +checklocksignore
    46  func (m *Mutex) Lock() {
    47  	locking.AddGLock(genericMarkIndex, -1)
    48  	m.mu.Lock()
    49  }
    50  
    51  // NestedLock locks m knowing that another lock of the same type is held.
    52  // +checklocksignore
    53  func (m *Mutex) NestedLock(i lockNameIndex) {
    54  	locking.AddGLock(genericMarkIndex, int(i))
    55  	m.mu.Lock()
    56  }
    57  
    58  // Unlock unlocks m.
    59  // +checklocksignore
    60  func (m *Mutex) Unlock() {
    61  	locking.DelGLock(genericMarkIndex, -1)
    62  	m.mu.Unlock()
    63  }
    64  
    65  // NestedUnlock unlocks m knowing that another lock of the same type is held.
    66  // +checklocksignore
    67  func (m *Mutex) NestedUnlock(i lockNameIndex) {
    68  	locking.DelGLock(genericMarkIndex, int(i))
    69  	m.mu.Unlock()
    70  }
    71  
    72  // DO NOT REMOVE: The following function is automatically replaced.
    73  func initLockNames() {}
    74  
    75  func init() {
    76  	initLockNames()
    77  	genericMarkIndex = locking.NewMutexClass(reflect.TypeOf(Mutex{}), lockNames)
    78  }