Read-Write Ticket Lock

Read-Write Ticket Lock. More...

Data Structures
struct	rwlock_t
	Read-Write Ticket Lock structure. More...

Macros
#define	RWLOCK_DEADLOCK_TIMEOUT   (CLOCKS_PER_SEC * 10)
	Maximum time before we consider a deadlock to have occurred.
#define	RWLOCK_READ_SCOPE(lock)
	Acquires a rwlock for reading for the reminder of the current scope.
#define	RWLOCK_WRITE_SCOPE(lock)
	Acquires a rwlock for writing for the reminder of the current scope.
#define	RWLOCK_CREATE
	Create a rwlock initializer.

Functions
void	rwlock_init (rwlock_t *lock)
	Initializes a rwlock.
void	rwlock_read_acquire (rwlock_t *lock)
	Acquires a rwlock for reading, blocking until it is available.
void	rwlock_read_release (rwlock_t *lock)
	Releases a rwlock from reading.
void	rwlock_write_acquire (rwlock_t *lock)
	Acquires a rwlock for writing, blocking until it is available.
void	rwlock_write_release (rwlock_t *lock)
	Releases a rwlock from writing.
static void	rwlock_read_cleanup (rwlock_t **lock)
static void	rwlock_write_cleanup (rwlock_t **lock)

Detailed Description

Read-Write Ticket Lock.

Macro Definition Documentation

RWLOCK_CREATE

#define RWLOCK_CREATE

Value:

    (rwlock_t) \
    { \
        .readTicket = ATOMIC_VAR_INIT(0), .readServe = ATOMIC_VAR_INIT(0), .writeTicket = ATOMIC_VAR_INIT(0), \
        .writeServe = ATOMIC_VAR_INIT(0), .activeReaders = ATOMIC_VAR_INIT(0), .activeWriter = ATOMIC_VAR_INIT(false) \
    }

Create a rwlock initializer.

Returns

A rwlock_t initializer.

Definition at line 45 of file rwlock.h.

RWLOCK_DEADLOCK_TIMEOUT

#define RWLOCK_DEADLOCK_TIMEOUT   (CLOCKS_PER_SEC * 10)

Maximum time before we consider a deadlock to have occurred.

Definition at line 20 of file rwlock.h.

RWLOCK_READ_SCOPE

#define RWLOCK_READ_SCOPE

(

lock

)

Value:

    __attribute__((cleanup(rwlock_read_cleanup))) rwlock_t* CONCAT(rl, __COUNTER__) = (lock); \
    rwlock_read_acquire((lock))

Acquires a rwlock for reading for the reminder of the current scope.

Parameters

lock	Pointer to the rwlock to acquire.

Definition at line 27 of file rwlock.h.

RWLOCK_WRITE_SCOPE

#define RWLOCK_WRITE_SCOPE

(

lock

)

Value:

    __attribute__((cleanup(rwlock_write_cleanup))) rwlock_t* CONCAT(wl, __COUNTER__) = (lock); \
    rwlock_write_acquire((lock))

Acquires a rwlock for writing for the reminder of the current scope.

Parameters

lock	Pointer to the rwlock to acquire.

Definition at line 36 of file rwlock.h.

Function Documentation

rwlock_init()

void rwlock_init

(

rwlock_t *

lock

)

Initializes a rwlock.

Parameters

lock	Pointer to the rwlock to initialize.

Definition at line 8 of file rwlock.c.

References rwlock_t::activeReaders, rwlock_t::activeWriter, atomic_init, lock, rwlock_t::readServe, rwlock_t::readTicket, rwlock_t::writeServe, and rwlock_t::writeTicket.

Referenced by key_init(), local_listen_dir_init(), namespace_init(), process_init(), vfs_list_init(), and vfs_map_init().

rwlock_read_acquire()

void rwlock_read_acquire

(

rwlock_t *

lock

)

Acquires a rwlock for reading, blocking until it is available.

Parameters

lock	Pointer to the rwlock to acquire.

Definition at line 18 of file rwlock.c.

References rwlock_t::activeReaders, atomic_fetch_add, atomic_load, atomic_thread_fence, interrupt_disable(), lock, memory_order_seq_cst, NULL, panic(), rwlock_t::readServe, rwlock_t::readTicket, RWLOCK_DEADLOCK_TIMEOUT, start(), timer_uptime(), rwlock_t::writeServe, and rwlock_t::writeTicket.

Referenced by namespace_get_root_path().

rwlock_read_cleanup()

static void rwlock_read_cleanup ( rwlock_t **  lock )

inlinestatic

Definition at line 103 of file rwlock.h.

References lock, and rwlock_read_release().

rwlock_read_release()

void rwlock_read_release

(

rwlock_t *

lock

)

Releases a rwlock from reading.

Parameters

lock	Pointer to the rwlock to release.

Definition at line 57 of file rwlock.c.

References rwlock_t::activeReaders, atomic_fetch_add, atomic_fetch_sub, interrupt_enable(), lock, and rwlock_t::readServe.

Referenced by namespace_get_root_path(), and rwlock_read_cleanup().

rwlock_write_acquire()

void rwlock_write_acquire

(

rwlock_t *

lock

)

Acquires a rwlock for writing, blocking until it is available.

Parameters

lock	Pointer to the rwlock to acquire.

Definition at line 65 of file rwlock.c.

References rwlock_t::activeReaders, rwlock_t::activeWriter, atomic_compare_exchange_weak, atomic_fetch_add, atomic_load, atomic_thread_fence, interrupt_disable(), lock, memory_order_seq_cst, NULL, panic(), RWLOCK_DEADLOCK_TIMEOUT, start(), timer_uptime(), rwlock_t::writeServe, and rwlock_t::writeTicket.

Referenced by local_listen_free(), namespace_bind(), namespace_deinit(), namespace_mount(), and process_free().

rwlock_write_cleanup()

static void rwlock_write_cleanup ( rwlock_t **  lock )

inlinestatic

Definition at line 108 of file rwlock.h.

References lock, and rwlock_write_release().

rwlock_write_release()

void rwlock_write_release

(

rwlock_t *

lock

)

Releases a rwlock from writing.

Parameters

lock	Pointer to the rwlock to release.

Definition at line 116 of file rwlock.c.

References rwlock_t::activeWriter, atomic_fetch_add, atomic_store, interrupt_enable(), lock, and rwlock_t::writeServe.

Referenced by local_listen_free(), namespace_bind(), namespace_deinit(), namespace_mount(), process_free(), and rwlock_write_cleanup().