kernel/doc/synchronization

   1
   2                                  SPINNING LOCKS
   3                 spinlock_lock, spinlock_trylock, spinlock_unlock
   4                                  +------------+
   5                                  | spinlock_t |
   6                                  +------------+
   7                                        |
   8                                        +------------------------------+
   9                                                                       |
  10                       INTERRUPTS-DISABLED SPINNING LOCKS              |
  11        irq_spinlock_lock, irq_spinlock_trylock, irq_spinlock_unlock   |
  12                                +----------------+                     |
  13                                | irq_spinlock_t |<--------------------+
  14                                +----------------+
  15
  16
  17
  18                                    WAIT QUEUES
  19                          waitq_sleep_timeout, waitq_wakeup
  20                                    +---------+
  21                                    | waitq_t |
  22                                    +---------+
  23                                   /           \
  24                SEMAPHORES        /             \  CONDITION VARIABLES
  25  semaphore_down_timeout, semaphore_up    condvar_wait_timeout, condvar_signal
  26             +--------------+   /                 \   +-----------+
  27             | semaphore_t  |<-+                   +->| condvar_t |
  28             +--------------+                         +-----------+
  29                    |                                       ^
  30                    |                                       |
  31                    |                                +------+
  32                    V                               /
  33                 MUTEXES                           / READERS/WRITERS LOCKS
  34     mutex_lock_timeout, mutex_unlock   rwlock_reader/writer_lock_timeout, rwlock_unlock
  35               +---------+                       /        +----------+
  36               | mutex_t |------------------------------->| rwlock_t |
  37               +---------+                     /          +----------+
  38                    |                         /
  39                    +------------------------+