lock_set_recursive Kernel Service
Purpose
Prepares a complex lock for recursive use.
Syntax
#include <sys/lock_def.h>void lock_set_recursive (lock_addr)
complex_lock_t lock_addr;
complex_lock_t lock_addr;
Parameter
| Item | Description |
|---|---|
| lock_addr | Specifies the address of the lock word to be prepared for recursive use. |
Description
The lock_set_recursive kernel service prepares the specified complex lock for recursive use. A complex lock cannot be nested until the lock_set_recursive kernel service is called for it. The calling kernel thread must hold the specified complex lock in write-exclusive mode.
When a complex lock is used recursively, the lock_done kernel service must be called once for each time that the thread is locked in order to unlock the lock.
Only the kernel thread which calls the lock_set_recursive kernel service for a lock may acquire that lock recursively.
Note: The lock_set_recursive and lock_clear_recursive kernel services must be used in
pairs and must be called only when recursion is likely to occur. The lock_set_recursive
kernel service must be called after making a call to the lock_write kernel service and the
lock_clear_recursive kernel service must be called before making the call to the
lock_done kernel service in routines where recursion might occur down the call stack.
Execution Environment
The lock_set_recursive kernel service can be called from process environment only.
Return Values
The lock_set_recursive kernel service has no return values.