acpi/acpica/utlock.c

4  * Module Name: utlock - Reader/Writer lock interfaces
21  * PARAMETERS:  lock                - Pointer to a valid RW lock
25  * DESCRIPTION: Reader/writer lock creation and deletion interfaces.
28 acpi_status acpi_ut_create_rw_lock(struct acpi_rw_lock *lock)
32 	lock->num_readers = 0;
33 	status = acpi_os_create_mutex(&lock->reader_mutex);
38 	status = acpi_os_create_mutex(&lock->writer_mutex);
42 void acpi_ut_delete_rw_lock(struct acpi_rw_lock *lock)
45 	acpi_os_delete_mutex(lock->reader_mutex);
46 	acpi_os_delete_mutex(lock->writer_mutex);
48 	lock->num_readers = 0;
49 	lock->reader_mutex = NULL;
50 	lock->writer_mutex = NULL;
58  * PARAMETERS:  lock                - Pointer to a valid RW lock
71 acpi_status acpi_ut_acquire_read_lock(struct acpi_rw_lock *lock)
75 	status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER);
80 	/* Acquire the write lock only for the first reader */
82 	lock->num_readers++;
83 	if (lock->num_readers == 1) {
85 		    acpi_os_acquire_mutex(lock->writer_mutex,
89 	acpi_os_release_mutex(lock->reader_mutex);
93 acpi_status acpi_ut_release_read_lock(struct acpi_rw_lock *lock)
97 	status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER);
102 	/* Release the write lock only for the very last reader */
104 	lock->num_readers--;
105 	if (lock->num_readers == 0) {
106 		acpi_os_release_mutex(lock->writer_mutex);
109 	acpi_os_release_mutex(lock->reader_mutex);
118  * PARAMETERS:  lock                - Pointer to a valid RW lock
123  *              release the writer mutex associated with the lock. Acquisition
124  *              of the lock is fully exclusive and will block all readers and
129 acpi_status acpi_ut_acquire_write_lock(struct acpi_rw_lock *lock)
133 	status = acpi_os_acquire_mutex(lock->writer_mutex, ACPI_WAIT_FOREVER);
137 void acpi_ut_release_write_lock(struct acpi_rw_lock *lock)
140 	acpi_os_release_mutex(lock->writer_mutex);