posix: deprecate PTHREAD_RWLOCK for POSIX_READER_WRITER_LOCKS

This change deprecates CONFIG_PTHREAD_RWLOCK in favour of
CONFIG_POSIX_READER_WRITER_LOCKS, which maps directly to the
name of the standard POSIX Option.

Annoyingly, the POSIX_RW_LOCKS Option Group is inconsistently
named. However, it is more convenient for us to use the Option
name since it is also the format used by the sysconf() variable
(_SC_READER_WRITER_LOCKS).

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

doc/services/portability/posix/conformance/index.rst

@@ -66,7 +66,7 @@ POSIX System Interfaces
     :ref:`_POSIX_CLOCK_SELECTION<posix_option_group_clock_selection>`, 200809L, :kconfig:option:`CONFIG_POSIX_CLOCK_SELECTION`
     _POSIX_MAPPED_FILES, -1, :ref:`†<posix_undefined_behaviour>`
     _POSIX_MEMORY_PROTECTION, -1, :ref:`†<posix_undefined_behaviour>`
-    :ref:`_POSIX_READER_WRITER_LOCKS<posix_option_reader_writer_locks>`, 200809L, :kconfig:option:`CONFIG_PTHREAD_IPC`
+    :ref:`_POSIX_READER_WRITER_LOCKS<posix_option_reader_writer_locks>`, 200809L, :kconfig:option:`CONFIG_POSIX_READER_WRITER_LOCKS`
     :ref:`_POSIX_REALTIME_SIGNALS<posix_option_group_realtime_signals>`, -1,
     :ref:`_POSIX_SEMAPHORES<posix_option_group_semaphores>`, 200809L, :kconfig:option:`CONFIG_PTHREAD_IPC`
     :ref:`_POSIX_SPIN_LOCKS<posix_option_group_spin_locks>`, 200809L, :kconfig:option:`CONFIG_POSIX_SPIN_LOCKS`

include/zephyr/posix/posix_features.h

@@ -71,7 +71,7 @@
 #define _POSIX_RAW_SOCKETS _POSIX_VERSION
 #endif
 
-#ifdef CONFIG_PTHREAD_IPC
+#ifdef CONFIG_POSIX_READER_WRITER_LOCKS
 #define _POSIX_READER_WRITER_LOCKS _POSIX_VERSION
 #endif
 

include/zephyr/posix/pthread.h

@@ -153,7 +153,7 @@ int pthread_condattr_setclock(pthread_condattr_t *att, clockid_t clock_id);
  *
  * Initialize a rwlock with the default rwlock attributes.
  */
-#define PTHREAD_RWLOCK_INITIALIZER (-1)
+#define POSIX_RWLOCK_INITIALIZER (-1)
 
 /*
  *  Mutex attributes - type

include/zephyr/posix/sys/sysconf.h

@@ -168,7 +168,7 @@ enum {
 	COND_CODE_1(CONFIG_NET_SOCKETS_PACKET, (_POSIX_RAW_SOCKETS), (-1L))
 #define __z_posix_sysconf_SC_RE_DUP_MAX _POSIX_RE_DUP_MAX
 #define __z_posix_sysconf_SC_READER_WRITER_LOCKS                                                   \
-	COND_CODE_1(CONFIG_PTHREAD_IPC, (_POSIX_READER_WRITER_LOCKS), (-1L))
+	COND_CODE_1(CONFIG_POSIX_READER_WRITER_LOCKS, (_POSIX_READER_WRITER_LOCKS), (-1L))
 #define __z_posix_sysconf_SC_REALTIME_SIGNALS      (-1L)
 #define __z_posix_sysconf_SC_REGEXP                (-1L)
 #define __z_posix_sysconf_SC_SAVED_IDS             (-1L)

lib/posix/options/CMakeLists.txt

@@ -73,8 +73,8 @@ zephyr_library_sources_ifdef(CONFIG_PTHREAD_COND cond.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD_KEY key.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD_MUTEX mutex.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD pthread.c)
-zephyr_library_sources_ifdef(CONFIG_PTHREAD_RWLOCK rwlock.c)
 zephyr_library_sources_ifdef(CONFIG_POSIX_PRIORITY_SCHEDULING sched.c)
+zephyr_library_sources_ifdef(CONFIG_POSIX_READER_WRITER_LOCKS rwlock.c)
 zephyr_library_sources_ifdef(CONFIG_PTHREAD_IPC semaphore.c)
 
 zephyr_library_include_directories(

lib/posix/options/Kconfig.deprecated

@@ -120,6 +120,15 @@ config PTHREAD_BARRIER
 
 	  Please use CONFIG_POSIX_BARRIERS instead.
 
+config PTHREAD_RWLOCK
+	bool "pthread_spinlock_t support [DEPRECATED]"
+	select DEPRECATED
+	select POSIX_READER_WRITER_LOCKS
+	help
+	  This option is deprecated.
+
+	  Please use CONFIG_POSIX_READER_WRITER_LOCKS instead.
+
 config PTHREAD_SPINLOCK
 	bool "pthread_spinlock_t support [DEPRECATED]"
 	select DEPRECATED

lib/posix/options/Kconfig.rwlock

@@ -2,7 +2,27 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-TYPE = PTHREAD_RWLOCK
+menuconfig POSIX_READER_WRITER_LOCKS
-type = pthread_rwlock_t
+	bool "POSIX reader-writer locks"
-type-function = pthread_rwlock_timedrdlock
+	default y if POSIX_API
-rsource "Kconfig.template.pooled_ipc_type"
+	help
+	  Select 'y' here to enable POSIX reader-writer locks.
+
+	  For more information please see
+	  https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_subprofiles.html
+
+if POSIX_READER_WRITER_LOCKS
+
+config MAX_PTHREAD_RWLOCK_COUNT
+	int "Maximum number of POSIX reader-writer locks"
+	default 5
+	help
+	  Maximum simultaneously active reader-writer locks in a POSIX application.
+
+	  Note: this is a non-standard option.
+
+module = PTHREAD_RWLOCK
+module-str = POSIX Reader-Writer Locks
+source "subsys/logging/Kconfig.template.log_config"
+
+endif # POSIX_READER_WRITER_LOCKS

lib/posix/options/rwlock.c

@@ -86,7 +86,7 @@ struct posix_rwlock *to_posix_rwlock(pthread_rwlock_t *rwlock)
 	size_t bit;
 	struct posix_rwlock *rwl;
 
-	if (*rwlock != PTHREAD_RWLOCK_INITIALIZER) {
+	if (*rwlock != POSIX_RWLOCK_INITIALIZER) {
 		return get_posix_rwlock(*rwlock);
 	}
 
@@ -116,7 +116,7 @@ int pthread_rwlock_init(pthread_rwlock_t *rwlock,
 	struct posix_rwlock *rwl;
 
 	ARG_UNUSED(attr);
-	*rwlock = PTHREAD_RWLOCK_INITIALIZER;
+	*rwlock = POSIX_RWLOCK_INITIALIZER;
 
 	rwl = to_posix_rwlock(rwlock);
 	if (rwl == NULL) {

tests/posix/headers/src/pthread_h.c

@@ -59,7 +59,7 @@ ZTEST(posix_headers, test_pthread_h)
 
 	pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 	pthread_mutex_t mu = PTHREAD_MUTEX_INITIALIZER;
-	/* pthread_rwlock_t lock = PTHREAD_RWLOCK_INITIALIZER; */ /* not implemented */
+	/* pthread_rwlock_t lock = POSIX_READER_WRITER_LOCKS_INITIALIZER; */ /* not implemented */
 
 	zassert_not_null(pthread_atfork);
 	zassert_not_null(pthread_attr_destroy);