rationalize osdMutex

Avoids split allocation.
Eliminates special case free-list.

win32: eliminate pre-XP
rtems-score: eliminate non-fast

modules/libcom/src/misc/epicsExit.c

@@ -35,8 +35,6 @@
 #include "cantProceed.h"
 #include "epicsExit.h"
 
-void epicsMutexCleanup(void);
-
 typedef struct exitNode {
     ELLNODE         node;
     epicsExitFunc   func;
@@ -115,8 +113,6 @@ LIBCOM_API void epicsExitCallAtExits(void)
         epicsExitCallAtExitsPvt ( pep );
         destroyExitPvt ( pep );
     }
-    /* Handle specially to avoid circular reference */
-    epicsMutexCleanup();
 }
 
 LIBCOM_API void epicsExitCallAtThreadExits(void)

modules/libcom/src/osi/epicsMutex.cpp

@@ -26,30 +26,23 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "dbDefs.h"
 #include "epicsStdio.h"
 #include "epicsThread.h"
-#include "valgrind/valgrind.h"
 #include "ellLib.h"
 #include "errlog.h"
 #include "epicsMutex.h"
+#include "epicsMutexImpl.h"
 #include "epicsThread.h"
+#include "cantProceed.h"
 
-static epicsThreadOnceId epicsMutexOsiOnce = EPICS_THREAD_ONCE_INIT;
-static ELLLIST mutexList;
-static ELLLIST freeList;
-
-struct epicsMutexParm {
-    ELLNODE node;
-    epicsMutexOSD * id;
-#   ifdef LOG_LAST_OWNER
-        epicsThreadId lastOwner;
-#   endif
-    const char *pFileName;
-    int lineno;
-};
-
-static epicsMutexOSD * epicsMutexGlobalLock;
+static ELLLIST mutexList = ELLLIST_INIT;
 
+/* Specially initialized to bootstrap initialization.
+ * When supported (posix and !rtems) use statically initiallized mutex.
+ * Otherwise, initialize via epicsMutexOsdSetup().
+ */
+struct epicsMutexParm epicsMutexGlobalLock = {ELLNODE_INIT, __FILE__, __LINE__};
 
 // vxWorks 5.4 gcc fails during compile when I use std::exception
 using namespace std;
@@ -76,176 +69,82 @@ const char * epicsMutex::invalidMutex::what () const throw ()
     return "epicsMutex::invalidMutex()";
 }
 
-static void epicsMutexOsiInit(void *) {
-    ellInit(&mutexList);
-    ellInit(&freeList);
-    VALGRIND_CREATE_MEMPOOL(&freeList, 0, 0);
-    epicsMutexGlobalLock = epicsMutexOsdCreate();
-}
-
 epicsMutexId epicsStdCall epicsMutexOsiCreate(
     const char *pFileName,int lineno)
 {
-    epicsMutexOSD * id;
+    epicsMutexOsdSetup();
 
-    epicsThreadOnce(&epicsMutexOsiOnce, epicsMutexOsiInit, NULL);
+    epicsMutexId ret = (epicsMutexId)calloc(1, sizeof(*ret));
+    if(ret) {
+        ret->pFileName = pFileName;
+        ret->lineno = lineno;
+
+        if(!epicsMutexOsdPrepare(ret)) {
+            epicsMutexMustLock(&epicsMutexGlobalLock);
+            ellAdd(&mutexList, &ret->node);
+            (void)epicsMutexUnlock(&epicsMutexGlobalLock);
+
+        } else {
+            free(ret);
+            ret = NULL;
+        }
 
-    id = epicsMutexOsdCreate();
-    if(!id) {
-        return 0;
-    }
-    epicsMutexLockStatus lockStat =
-        epicsMutexOsdLock(epicsMutexGlobalLock);
-    assert ( lockStat == epicsMutexLockOK );
-    epicsMutexParm *pmutexNode =
-        reinterpret_cast < epicsMutexParm * > ( ellFirst(&freeList) );
-    if(pmutexNode) {
-        ellDelete(&freeList,&pmutexNode->node);
-        VALGRIND_MEMPOOL_FREE(&freeList, pmutexNode);
-    } else {
-        pmutexNode = static_cast < epicsMutexParm * > ( calloc(1,sizeof(epicsMutexParm)) );
     }
-    VALGRIND_MEMPOOL_ALLOC(&freeList, pmutexNode, sizeof(epicsMutexParm));
-    pmutexNode->id = id;
-#   ifdef LOG_LAST_OWNER
-        pmutexNode->lastOwner = 0;
-#   endif
-    pmutexNode->pFileName = pFileName;
-    pmutexNode->lineno = lineno;
-    ellAdd(&mutexList,&pmutexNode->node);
-    epicsMutexOsdUnlock(epicsMutexGlobalLock);
-    return(pmutexNode);
+    return ret;
 }
 
 epicsMutexId epicsStdCall epicsMutexOsiMustCreate(
     const char *pFileName,int lineno)
 {
     epicsMutexId id = epicsMutexOsiCreate(pFileName,lineno);
-    assert(id);
-    return(id );
+    if(!id) {
+        cantProceed("epicsMutexOsiMustCreate() fails at %s:%d\n",
+                    pFileName, lineno);
+    }
+    return id;
 }
 
 void epicsStdCall epicsMutexDestroy(epicsMutexId pmutexNode)
 {
-    epicsMutexLockStatus lockStat =
-        epicsMutexOsdLock(epicsMutexGlobalLock);
-    assert ( lockStat == epicsMutexLockOK );
-    ellDelete(&mutexList,&pmutexNode->node);
-    epicsMutexOsdDestroy(pmutexNode->id);
-    VALGRIND_MEMPOOL_FREE(&freeList, pmutexNode);
-    VALGRIND_MEMPOOL_ALLOC(&freeList, &pmutexNode->node, sizeof(pmutexNode->node));
-    ellAdd(&freeList,&pmutexNode->node);
-    epicsMutexOsdUnlock(epicsMutexGlobalLock);
-}
-
-void epicsStdCall epicsMutexUnlock(epicsMutexId pmutexNode)
-{
-    epicsMutexOsdUnlock(pmutexNode->id);
-}
-
-epicsMutexLockStatus epicsStdCall epicsMutexLock(
-    epicsMutexId pmutexNode)
-{
-    epicsMutexLockStatus status =
-        epicsMutexOsdLock(pmutexNode->id);
-#   ifdef LOG_LAST_OWNER
-        if ( status == epicsMutexLockOK ) {
-            pmutexNode->lastOwner = epicsThreadGetIdSelf();
-        }
-#   endif
-    return status;
-}
-
-epicsMutexLockStatus epicsStdCall epicsMutexTryLock(
-    epicsMutexId pmutexNode)
-{
-    epicsMutexLockStatus status =
-        epicsMutexOsdTryLock(pmutexNode->id);
-#   ifdef LOG_LAST_OWNER
-        if ( status == epicsMutexLockOK ) {
-            pmutexNode->lastOwner = epicsThreadGetIdSelf();
-        }
-#   endif
-    return status;
-}
-
-/* Empty the freeList.
- * Called from epicsExit.c, but not via epicsAtExit()
- * to avoid the possibility of a circular reference.
- */
-extern "C"
-void epicsMutexCleanup(void)
-{
-    ELLNODE *cur;
-    epicsMutexLockStatus lockStat =
-        epicsMutexOsdLock(epicsMutexGlobalLock);
-    assert ( lockStat == epicsMutexLockOK );
-
-    while((cur=ellGet(&freeList))!=NULL) {
-        VALGRIND_MEMPOOL_FREE(&freeList, cur);
-        free(cur);
+    if(pmutexNode) {
+        epicsMutexMustLock(&epicsMutexGlobalLock);
+        ellDelete(&mutexList, &pmutexNode->node);
+        (void)epicsMutexUnlock(&epicsMutexGlobalLock);
+        epicsMutexOsdCleanup(pmutexNode);
+        free(pmutexNode);
     }
-
-    epicsMutexOsdUnlock(epicsMutexGlobalLock);
 }
 
 void epicsStdCall epicsMutexShow(
     epicsMutexId pmutexNode, unsigned  int level)
 {
-#   ifdef LOG_LAST_OWNER
-        char threadName [255];
-        if ( pmutexNode->lastOwner ) {
-#           error currently not safe to fetch name for stale thread
-            epicsThreadGetName ( pmutexNode->lastOwner,
-                threadName, sizeof ( threadName ) );
-        }
-        else {
-            strcpy ( threadName, "<not used>" );
-        }
-        printf("epicsMutexId %p last owner \"%s\" source %s line %d\n",
-            (void *)pmutexNode, threadName,
-            pmutexNode->pFileName, pmutexNode->lineno);
-#   else
-        printf("epicsMutexId %p source %s line %d\n",
-            (void *)pmutexNode, pmutexNode->pFileName,
-            pmutexNode->lineno);
-#   endif
+    printf("epicsMutexId %p source %s line %d\n",
+           (void *)pmutexNode, pmutexNode->pFileName,
+           pmutexNode->lineno);
     if ( level > 0 ) {
-        epicsMutexOsdShow(pmutexNode->id,level-1);
+        epicsMutexOsdShow(pmutexNode,level-1);
     }
 }
 
 void epicsStdCall epicsMutexShowAll(int onlyLocked,unsigned  int level)
 {
-    epicsMutexParm *pmutexNode;
-
-    if (epicsMutexOsiOnce == EPICS_THREAD_ONCE_INIT)
-        return;
+    epicsMutexOsdSetup();
 
-    printf("ellCount(&mutexList) %d ellCount(&freeList) %d\n",
-        ellCount(&mutexList),ellCount(&freeList));
+    printf("ellCount(&mutexList) %d\n", ellCount(&mutexList));
     epicsMutexOsdShowAll();
-    epicsMutexLockStatus lockStat =
-        epicsMutexOsdLock(epicsMutexGlobalLock);
-    assert ( lockStat == epicsMutexLockOK );
-    pmutexNode = reinterpret_cast < epicsMutexParm * > ( ellFirst(&mutexList) );
-    while(pmutexNode) {
+    epicsMutexMustLock(&epicsMutexGlobalLock);
+    for(ELLNODE *cur =ellFirst(&mutexList); cur; cur = ellNext(cur)) {
+        epicsMutexParm *lock = CONTAINER(cur, epicsMutexParm, node);
         if(onlyLocked) {
-            epicsMutexLockStatus status;
-            status = epicsMutexOsdTryLock(pmutexNode->id);
-            if(status==epicsMutexLockOK) {
-                epicsMutexOsdUnlock(pmutexNode->id);
-                pmutexNode =
-                    reinterpret_cast < epicsMutexParm * >
-                        ( ellNext(&pmutexNode->node) );
-                continue;
+            // cycle through to test state
+            if(epicsMutexTryLock(lock)==epicsMutexLockOK) {
+                epicsMutexUnlock(lock);
+                continue; // was not locked, skip
             }
         }
-        epicsMutexShow(pmutexNode, level);
-        pmutexNode =
-            reinterpret_cast < epicsMutexParm * > ( ellNext(&pmutexNode->node) );
+        epicsMutexShow(lock, level);
     }
-    epicsMutexOsdUnlock(epicsMutexGlobalLock);
+    epicsMutexUnlock(&epicsMutexGlobalLock);
 }
 
 #if !defined(__GNUC__) || __GNUC__<4 || (__GNUC__==4 && __GNUC_MINOR__<8)

modules/libcom/src/osi/epicsMutex.h

@@ -247,21 +247,6 @@ LIBCOM_API void epicsStdCall epicsMutexShow(
 LIBCOM_API void epicsStdCall epicsMutexShowAll(
     int onlyLocked,unsigned  int level);
 
-/**@privatesection
- * The following are interfaces to the OS dependent
- * implementation and should NOT be called directly by
- * user code.
- */
-struct epicsMutexOSD * epicsMutexOsdCreate(void);
-void epicsMutexOsdDestroy(struct epicsMutexOSD *);
-void epicsMutexOsdUnlock(struct epicsMutexOSD *);
-epicsMutexLockStatus epicsMutexOsdLock(struct epicsMutexOSD *);
-epicsMutexLockStatus epicsMutexOsdTryLock(struct epicsMutexOSD *);
-void epicsMutexOsdShow(struct epicsMutexOSD *,unsigned  int level);
-#ifdef EPICS_PRIVATE_API
-void epicsMutexOsdShowAll(void);
-#endif
-
 #ifdef __cplusplus
 }
 #endif

modules/libcom/src/osi/epicsMutexImpl.h

@@ -0,0 +1,66 @@
+/*************************************************************************\
+* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
+*     National Laboratory.
+* Copyright (c) 2002 The Regents of the University of California, as
+*     Operator of Los Alamos National Laboratory.
+* Copyright (c) 2023 Michael Davidsaver
+* SPDX-License-Identifier: EPICS
+* EPICS BASE is distributed subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution.
+\*************************************************************************/
+
+/* Only include from osdMutex.c */
+
+#ifndef epicsMutexImpl_H
+#define epicsMutexImpl_H
+
+#if defined(vxWorks)
+#  include <vxWorks.h>
+#  include <semLib.h>
+#elif defined(_WIN32)
+#  define VC_EXTRALEAN
+#  define WIN32_LEAN_AND_MEAN
+#  include <windows.h>
+#elif defined(__rtems__)
+#  include <rtems.h>
+#  include <rtems/score/cpuopts.h>
+#else
+#  include <pthread.h>
+#endif
+
+#include "ellLib.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct epicsMutexParm {
+    /* global list of mutex */
+    ELLNODE node;
+    /* location where mutex was allocated */
+    const char *pFileName;
+    int lineno;
+#if defined(vxWorks)
+    SEM_ID osd;
+#elif defined(_WIN32)
+    CRITICAL_SECTION osd;
+#elif defined(__RTEMS_MAJOR__) && __RTEMS_MAJOR__<5
+    Semaphore_Control *osd;
+#else
+    pthread_mutex_t osd;
+#endif
+};
+
+void epicsMutexOsdSetup(void);
+long epicsMutexOsdPrepare(struct epicsMutexParm *);
+void epicsMutexOsdCleanup(struct epicsMutexParm *);
+void epicsMutexOsdShow(struct epicsMutexParm *,unsigned  int level);
+void epicsMutexOsdShowAll(void);
+
+extern struct epicsMutexParm epicsMutexGlobalLock;
+
+#ifdef __cplusplus
+} // extern "C
+#endif
+
+#endif // epicsMutexImpl_H