RWLock Handler

This handler encapsulates functionality which provides the foundation RWLock services used in all of the APIs supported by RTEMS. More...

Collaboration diagram for RWLock Handler:

Files
file	corerwlock.c
file	corerwlockobtainread.c
	Obtain RWLock for reading.
file	corerwlockobtainwrite.c
	RWLock Obtain for Writing.
file	corerwlockrelease.c
	Releases the RWLock.

Data Structures
struct	CORE_RWLock_Attributes
	The following defines the control block used to manage the attributes of each RWLock. More...
struct	CORE_RWLock_Control
	The following defines the control block used to manage each RWLock. More...

Macros
#define	CORE_RWLOCK_STATUS_LAST   CORE_RWLOCK_TIMEOUT
	This is the last status value.
#define	CORE_RWLOCK_THREAD_WAITING_FOR_READ   0
	This is used to denote that a thread is blocking waiting for read-only access to the RWLock.
#define	CORE_RWLOCK_THREAD_WAITING_FOR_WRITE   1
	This is used to denote that a thread is blocking waiting for write-exclusive access to the RWLock.
#define	_CORE_RWLock_Flush(_the_rwlock, _remote_extract_callout, _status)
	This routine assists in the deletion of a RWLock by flushing the associated wait queue. More...

Typedefs
typedef void(*	CORE_RWLock_API_mp_support_callout) (Thread_Control *, Objects_Id)
	The following type defines the callout which the API provides to support global/multiprocessor operations on RWLocks.

Enumerations
enum	CORE_RWLock_States { CORE_RWLOCK_UNLOCKED, CORE_RWLOCK_LOCKED_FOR_READING, CORE_RWLOCK_LOCKED_FOR_WRITING }
	RWLock State. More...
enum	CORE_RWLock_Status { CORE_RWLOCK_SUCCESSFUL, CORE_RWLOCK_WAS_DELETED, CORE_RWLOCK_UNAVAILABLE, CORE_RWLOCK_TIMEOUT }
	Core RWLock handler return statuses. More...

Functions
void	_CORE_RWLock_Initialize (CORE_RWLock_Control *the_rwlock, CORE_RWLock_Attributes *the_rwlock_attributes)
	Initialize a RWlock. More...
RTEMS_INLINE_ROUTINE void	_CORE_RWLock_Destroy (CORE_RWLock_Control *the_rwlock)
void	_CORE_RWLock_Obtain_for_reading (CORE_RWLock_Control *the_rwlock, Thread_Control *executing, Objects_Id id, bool wait, Watchdog_Interval timeout, CORE_RWLock_API_mp_support_callout api_rwlock_mp_support)
	Obtain RWLock for reading. More...
void	_CORE_RWLock_Obtain_for_writing (CORE_RWLock_Control *the_rwlock, Thread_Control *executing, Objects_Id id, bool wait, Watchdog_Interval timeout, CORE_RWLock_API_mp_support_callout api_rwlock_mp_support)
	Obtain RWLock for writing. More...
CORE_RWLock_Status	_CORE_RWLock_Release (CORE_RWLock_Control *the_rwlock, Thread_Control *executing)
	Release the RWLock. More...
RTEMS_INLINE_ROUTINE void	_CORE_RWLock_Initialize_attributes (CORE_RWLock_Attributes *the_attributes)
	This method is used to initialize core rwlock attributes. More...

Detailed Description

This handler encapsulates functionality which provides the foundation RWLock services used in all of the APIs supported by RTEMS.

Macro Definition Documentation

_CORE_RWLock_Flush

#define _CORE_RWLock_Flush	(		_the_rwlock,
			_remote_extract_callout,
			_status
	)

Value:

_Thread_queue_Flush( \
    &((_the_rwlock)->Wait_queue), \
    (_remote_extract_callout), \
    (_status) \
  )

This routine assists in the deletion of a RWLock by flushing the associated wait queue.

Parameters

[in]	_the_rwlock	is the RWLock to flush
[in]	_remote_extract_callout	is the routine to invoke if the thread unblocked is remote
[in]	_status	is the status to be returned to the unblocked thread

Enumeration Type Documentation

CORE_RWLock_States

enum CORE_RWLock_States

RWLock State.

Enumerator
CORE_RWLOCK_UNLOCKED	This indicates the the RWLock is not currently locked.
CORE_RWLOCK_LOCKED_FOR_READING	This indicates the the RWLock is currently locked for reading.
CORE_RWLOCK_LOCKED_FOR_WRITING	This indicates the the RWLock is currently locked for reading.

CORE_RWLock_Status

enum CORE_RWLock_Status

Core RWLock handler return statuses.

Enumerator
CORE_RWLOCK_SUCCESSFUL	This status indicates that the operation completed successfully.
CORE_RWLOCK_WAS_DELETED	This status indicates that the thread was blocked waiting for an.
CORE_RWLOCK_UNAVAILABLE	This status indicates that the rwlock was not immediately available.
CORE_RWLOCK_TIMEOUT	This status indicates that the calling task was willing to block but the operation was unable to complete within the time allotted because the resource never became available.

Function Documentation

_CORE_RWLock_Initialize()

void _CORE_RWLock_Initialize	(	CORE_RWLock_Control *	the_rwlock,
		CORE_RWLock_Attributes *	the_rwlock_attributes
	)

Initialize a RWlock.

This routine initializes the RWLock based on the parameters passed.

Parameters

[in]	the_rwlock	is the RWLock to initialize
[in]	the_rwlock_attributes	define the behavior of this instance

References _Thread_queue_Initialize(), CORE_RWLock_Control::Attributes, CORE_RWLOCK_UNLOCKED, CORE_RWLock_Control::current_state, CORE_RWLock_Control::number_of_readers, and CORE_RWLock_Control::Wait_queue.

_CORE_RWLock_Initialize_attributes()

RTEMS_INLINE_ROUTINE void _CORE_RWLock_Initialize_attributes

(

CORE_RWLock_Attributes *

the_attributes

)

This method is used to initialize core rwlock attributes.

Parameters

[in]

the_attributes

pointer to the attributes to initialize.

References CORE_RWLock_Attributes::XXX.

_CORE_RWLock_Obtain_for_reading()

void _CORE_RWLock_Obtain_for_reading	(	CORE_RWLock_Control *	the_rwlock,
		Thread_Control *	executing,
		Objects_Id	id,
		bool	wait,
		Watchdog_Interval	timeout,
		CORE_RWLock_API_mp_support_callout	api_rwlock_mp_support
	)

Obtain RWLock for reading.

This routine attempts to obtain the RWLock for read access.

Parameters

[in]	the_rwlock	is the RWLock to wait for
[in]	id	is the id of the object being waited upon
[in]	wait	is true if the calling thread is willing to wait
[in]	timeout	is the number of ticks the calling thread is willing to wait if wait is true.
[in]	api_rwlock_mp_support	is the routine to invoke if the thread unblocked is remote

Note

Status is returned via the thread control block.

_CORE_RWLock_Obtain_for_writing()

void _CORE_RWLock_Obtain_for_writing	(	CORE_RWLock_Control *	the_rwlock,
		Thread_Control *	executing,
		Objects_Id	id,
		bool	wait,
		Watchdog_Interval	timeout,
		CORE_RWLock_API_mp_support_callout	api_rwlock_mp_support
	)

Obtain RWLock for writing.

This routine attempts to obtain the RWLock for write exclusive access.

Parameters

[in]	the_rwlock	is the RWLock to wait for
[in]	id	is the id of the object being waited upon
[in]	wait	is true if the calling thread is willing to wait
[in]	timeout	is the number of ticks the calling thread is willing to wait if wait is true.
[in]	api_rwlock_mp_support	is the routine to invoke if the thread unblocked is remote

Note

Status is returned via the thread control block.

_CORE_RWLock_Release()

CORE_RWLock_Status _CORE_RWLock_Release	(	CORE_RWLock_Control *	the_rwlock,
		Thread_Control *	executing
	)

Release the RWLock.

This routine manually releases the_rwlock. All of the threads waiting for the RWLock will be readied.

Parameters

[in]

the_rwlock

is the RWLock to surrender

Return values

Status

is returned to indicate successful or failure.