kernel/doc/synchronization

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