3  * Module Name: utlock - Reader/Writer lock interfaces
11  * Some or all of this work - Copyright (c) 1999 - 2025, Intel Corp.
28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
104  * re-exports any such software from a foreign destination, Licensee shall
105  * ensure that the distribution and export/re-export of the software is in
108  * any of its subsidiaries will export/re-export any technical data, process,
130  * 3. Neither the names of the above-listed copyright holders nor the names
165  * PARAMETERS:  Lock                - Pointer to a valid RW lock
167  * RETURN:      Status
169  * DESCRIPTION: Reader/writer lock creation and deletion interfaces.
175     ACPI_RW_LOCK            *Lock)  in AcpiUtCreateRwLock()  argument
177     ACPI_STATUS             Status;  in AcpiUtCreateRwLock()  local
180     Lock->NumReaders = 0;  in AcpiUtCreateRwLock()
181     Status = AcpiOsCreateMutex (&Lock->ReaderMutex);  in AcpiUtCreateRwLock()
182     if (ACPI_FAILURE (Status))  in AcpiUtCreateRwLock()
184         return (Status);  in AcpiUtCreateRwLock()
187     Status = AcpiOsCreateMutex (&Lock->WriterMutex);  in AcpiUtCreateRwLock()
188     return (Status);  in AcpiUtCreateRwLock()
194     ACPI_RW_LOCK            *Lock)  in AcpiUtDeleteRwLock()  argument
197     AcpiOsDeleteMutex (Lock->ReaderMutex);  in AcpiUtDeleteRwLock()
198     AcpiOsDeleteMutex (Lock->WriterMutex);  in AcpiUtDeleteRwLock()
200     Lock->NumReaders = 0;  in AcpiUtDeleteRwLock()
201     Lock->ReaderMutex = NULL;  in AcpiUtDeleteRwLock()
202     Lock->WriterMutex = NULL;  in AcpiUtDeleteRwLock()
211  * PARAMETERS:  Lock                - Pointer to a valid RW lock
213  * RETURN:      Status
226     ACPI_RW_LOCK            *Lock)  in AcpiUtAcquireReadLock()  argument
228     ACPI_STATUS             Status;  in AcpiUtAcquireReadLock()  local
231     Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER);  in AcpiUtAcquireReadLock()
232     if (ACPI_FAILURE (Status))  in AcpiUtAcquireReadLock()
234         return (Status);  in AcpiUtAcquireReadLock()
237     /* Acquire the write lock only for the first reader */  in AcpiUtAcquireReadLock()
239     Lock->NumReaders++;  in AcpiUtAcquireReadLock()
240     if (Lock->NumReaders == 1)  in AcpiUtAcquireReadLock()
242         Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER);  in AcpiUtAcquireReadLock()
245     AcpiOsReleaseMutex (Lock->ReaderMutex);  in AcpiUtAcquireReadLock()
246     return (Status);  in AcpiUtAcquireReadLock()
252     ACPI_RW_LOCK            *Lock)  in AcpiUtReleaseReadLock()  argument
254     ACPI_STATUS             Status;  in AcpiUtReleaseReadLock()  local
257     Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER);  in AcpiUtReleaseReadLock()
258     if (ACPI_FAILURE (Status))  in AcpiUtReleaseReadLock()
260         return (Status);  in AcpiUtReleaseReadLock()
263     /* Release the write lock only for the very last reader */  in AcpiUtReleaseReadLock()
265     Lock->NumReaders--;  in AcpiUtReleaseReadLock()
266     if (Lock->NumReaders == 0)  in AcpiUtReleaseReadLock()
268         AcpiOsReleaseMutex (Lock->WriterMutex);  in AcpiUtReleaseReadLock()
271     AcpiOsReleaseMutex (Lock->ReaderMutex);  in AcpiUtReleaseReadLock()
272     return (Status);  in AcpiUtReleaseReadLock()
281  * PARAMETERS:  Lock                - Pointer to a valid RW lock
283  * RETURN:      Status
286  *              release the writer mutex associated with the lock. Acquisition
287  *              of the lock is fully exclusive and will block all readers and
294     ACPI_RW_LOCK            *Lock)  in AcpiUtAcquireWriteLock()  argument
296     ACPI_STATUS             Status;  in AcpiUtAcquireWriteLock()  local
299     Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER);  in AcpiUtAcquireWriteLock()
300     return (Status);  in AcpiUtAcquireWriteLock()
306     ACPI_RW_LOCK            *Lock)  in AcpiUtReleaseWriteLock()  argument
309     AcpiOsReleaseMutex (Lock->WriterMutex);  in AcpiUtReleaseWriteLock()