MDEV-34530 dead code in the thr_rwlock.c

remove it

configure.cmake

@@ -414,6 +414,10 @@ CHECK_FUNCTION_EXISTS (vsnprintf HAVE_VSNPRINTF)
 CHECK_FUNCTION_EXISTS (memalign HAVE_MEMALIGN)
 CHECK_FUNCTION_EXISTS (nl_langinfo HAVE_NL_LANGINFO)
 
+IF(NOT HAVE_PTHREAD_RWLOCK_RDLOCK AND NOT HAVE_RWLOCK_INIT AND NOT WIN32)
+  MESSAGE(FATAL_ERROR "No usable rwlock implementation found")
+ENDIF()
+
 IF(HAVE_SYS_EVENT_H)
 CHECK_FUNCTION_EXISTS (kqueue HAVE_KQUEUE)
 ENDIF()

mysys/thr_rwlock.c

@@ -81,176 +81,7 @@ int my_rw_destroy(my_rw_lock_t* rwp)
 }
 
 #else
-
-/*
-  Source base from Sun Microsystems SPILT, simplified for MySQL use
-  -- Joshua Chamas
-  Some cleanup and additional code by Monty
-*/
-
-/*
-*  Multithreaded Demo Source
-*
-*  Copyright (C) 1995 by Sun Microsystems, Inc.
-* 
-*
-*  This file is a product of SunSoft, Inc. and is provided for
-*  unrestricted use provided that this legend is included on all
-*  media and as a part of the software program in whole or part.
-*  Users may copy, modify or distribute this file at will.
-*
-*  THIS FILE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
-*  THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
-*  PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
-*
-*  This file is provided with no support and without any obligation on the
-*  part of SunSoft, Inc. to assist in its use, correction, modification or
-*  enhancement.
-*
-*  SUNSOFT AND SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT
-*  TO THE INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS
-*  FILE OR ANY PART THEREOF.
-*
-*  IN NO EVENT WILL SUNSOFT OR SUN MICROSYSTEMS, INC. BE LIABLE FOR ANY
-*  LOST REVENUE OR PROFITS OR OTHER SPECIAL, INDIRECT AND CONSEQUENTIAL
-*  DAMAGES, EVEN IF THEY HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
-*  DAMAGES.
-*
-*  SunSoft, Inc.
-*  2550 Garcia Avenue
-*  Mountain View, California  94043
-*/
-
-int my_rw_init(my_rw_lock_t *rwp)
-{
-  pthread_condattr_t	cond_attr;
-
-  pthread_mutex_init( &rwp->lock, MY_MUTEX_INIT_FAST);
-  pthread_condattr_init( &cond_attr );
-  pthread_cond_init( &rwp->readers, &cond_attr );
-  pthread_cond_init( &rwp->writers, &cond_attr );
-  pthread_condattr_destroy(&cond_attr);
-
-  rwp->state	= 0;
-  rwp->waiters	= 0;
-#ifdef SAFE_MUTEX
-  rwp->write_thread   = 0;
-#endif
-
-  return(0);
-}
-
-
-int my_rw_destroy(my_rw_lock_t *rwp)
-{
-  DBUG_ASSERT(rwp->state == 0);
-  pthread_mutex_destroy( &rwp->lock );
-  pthread_cond_destroy( &rwp->readers );
-  pthread_cond_destroy( &rwp->writers );
-  return(0);
-}
-
-
-int my_rw_rdlock(my_rw_lock_t *rwp)
-{
-  pthread_mutex_lock(&rwp->lock);
-
-  /* active or queued writers */
-  while (( rwp->state < 0 ) || rwp->waiters)
-    pthread_cond_wait( &rwp->readers, &rwp->lock);
-
-  rwp->state++;
-  pthread_mutex_unlock(&rwp->lock);
-  return(0);
-}
-
-int my_rw_tryrdlock(my_rw_lock_t *rwp)
-{
-  int res;
-  pthread_mutex_lock(&rwp->lock);
-  if ((rwp->state < 0 ) || rwp->waiters)
-    res= EBUSY;					/* Can't get lock */
-  else
-  {
-    res=0;
-    rwp->state++;
-  }
-  pthread_mutex_unlock(&rwp->lock);
-  return(res);
-}
-
-
-int my_rw_wrlock(my_rw_lock_t *rwp)
-{
-  pthread_mutex_lock(&rwp->lock);
-  rwp->waiters++;				/* another writer queued */
-
-  my_rw_lock_assert_not_write_owner(rwp);
-
-  while (rwp->state)
-    pthread_cond_wait(&rwp->writers, &rwp->lock);
-  rwp->state	= -1;
-  rwp->waiters--;
-#ifdef SAFE_MUTEX
-  rwp->write_thread= pthread_self();
-#endif
-  pthread_mutex_unlock(&rwp->lock);
-  return(0);
-}
-
-
-int my_rw_trywrlock(my_rw_lock_t *rwp)
-{
-  int res;
-
-  pthread_mutex_lock(&rwp->lock);
-  if (rwp->state)
-    res= EBUSY;					/* Can't get lock */    
-  else
-  {
-    res=0;
-    rwp->state	= -1;
-#ifdef SAFE_MUTEX
-  rwp->write_thread= pthread_self();
-#endif
-  }
-  pthread_mutex_unlock(&rwp->lock);
-  return(res);
-}
-
-
-int my_rw_unlock(my_rw_lock_t *rwp)
-{
-  DBUG_PRINT("rw_unlock",
-	     ("state: %d waiters: %d", rwp->state, rwp->waiters));
-  pthread_mutex_lock(&rwp->lock);
-
-  DBUG_ASSERT(rwp->state != 0);
-
-  if (rwp->state == -1)		/* writer releasing */
-  {
-    my_rw_lock_assert_write_owner(rwp);
-    rwp->state= 0;		/* mark as available */
-#ifdef SAFE_MUTEX
-    rwp->write_thread= 0;
-#endif
-
-    if ( rwp->waiters )		/* writers queued */
-      pthread_cond_signal( &rwp->writers );
-    else
-      pthread_cond_broadcast( &rwp->readers );
-  }
-  else
-  {
-    if ( --rwp->state == 0 &&   /* no more readers */
-        rwp->waiters)
-      pthread_cond_signal( &rwp->writers );
-  }
-
-  pthread_mutex_unlock( &rwp->lock );
-  return(0);
-}
-
+#error no pthread_rwlock_init
 #endif /* !defined _WIN32 */
 #endif /* NEED_MY_RW_LOCK*/