Changeset 93167 in vbox for trunk/src

Timestamp:

Jan 10, 2022 5:45:55 PM (3 years ago)

Author:

vboxsync

Message:

Guest Control/Main: Relaxed guest session locks a bit by using read locks instead of write locks where doable, as the internal event (de)registration has its own critical section and doesn't need to be protected by the object's write lock. Added some missing docs.

File:

• trunk/src/VBox/Main/src-client/GuestSessionImpl.cpp (modified) (23 diffs)

trunk/src/VBox/Main/src-client/GuestSessionImpl.cpp

@@ -666 +666 @@
  *                              was returned. Optional.
  *
- * @note    Takes the write lock.
+ * @note    Takes the read lock.
  */
 int GuestSession::i_closeSession(uint32_t uFlags, uint32_t uTimeoutMS, int *prcGuest)
@@ -674 +674 @@
     LogFlowThisFunc(("uFlags=%x, uTimeoutMS=%RU32\n", uFlags, uTimeoutMS));
 
-    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
 
     /* Guest Additions < 4.3 don't support closing dedicated
@@ -713 +713 @@
     LogFlowThisFunc(("Sending closing request to guest session ID=%RU32, uFlags=%x\n",
                      mData.mSession.mID, uFlags));
+
+    alock.release();
 
     VBOXHGCMSVCPARM paParms[4];
@@ -718 +720 @@
     HGCMSvcSetU32(&paParms[i++], pEvent->ContextID());
     HGCMSvcSetU32(&paParms[i++], uFlags);
-
-    alock.release(); /* Drop the write lock before waiting. */
 
     vrc = i_sendMessage(HOST_MSG_SESSION_CLOSE, i, paParms, VBOX_GUESTCTRL_DST_BOTH);
@@ -1089 +1089 @@
  * @param   prcGuest            Where to return the guest error when VERR_GSTCTL_GUEST_ERROR
  *                              was returned. Optional.
+ *
+ * @note    Takes the read lock.
  */
 int GuestSession::i_directoryRemove(const Utf8Str &strPath, uint32_t fFlags, int *prcGuest)
@@ -1097 +1099 @@
     LogFlowThisFunc(("strPath=%s, uFlags=0x%x\n", strPath.c_str(), fFlags));
 
-    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
 
     GuestWaitEvent *pEvent = NULL;
@@ -1112 +1114 @@
     HGCMSvcSetU32(&paParms[i++], fFlags);
 
-    alock.release(); /* Drop write lock before sending. */
+    alock.release(); /* Drop lock before sending. */
 
     vrc = i_sendMessage(HOST_MSG_DIR_REMOVE, i, paParms);
@@ -1311 +1313 @@
  * @param  pCtxCb               Host callback context.
  * @param  pSvcCb               Service callback data.
+ *
+ * @note   Takes the read lock.
  */
 int GuestSession::i_dispatchToObject(PVBOXGUESTCTRLHOSTCBCTX pCtxCb, PVBOXGUESTCTRLHOSTCALLBACK pSvcCb)
@@ -1959 +1963 @@
  * Called by IGuest right before this session gets removed from
  * the public session list.
+ *
+ * @note    Takes the write lock.
  */
 int GuestSession::i_onRemove(void)
@@ -2141 +2147 @@
  * @param   prcGuest            Where to return the guest error when VERR_GSTCTL_GUEST_ERROR
  *                              was returned. Optional.
+ *
+ * @note    Takes the write lock.
  */
 int GuestSession::i_startSession(int *prcGuest)
@@ -2167 +2175 @@
     /* Set current session status. */
     mData.mStatus = GuestSessionStatus_Starting;
-    mData.mRC = VINF_SUCCESS; /* Clear previous error, if any. */
+    mData.mRC     = VINF_SUCCESS; /* Clear previous error, if any. */
 
     int vrc;
@@ -2200 +2208 @@
     HGCMSvcSetU32(&paParms[i++], mData.mSession.mOpenFlags);
 
-    alock.release(); /* Drop write lock before sending. */
+    alock.release(); /* Drop lock before sending. */
 
     vrc = i_sendMessage(HOST_MSG_SESSION_CREATE, i, paParms, VBOX_GUESTCTRL_DST_ROOT_SVC);
@@ -2211 +2219 @@
     else
     {
+        alock.acquire(); /* Re-aquire lock before changing status. */
+
         /*
          * Unable to start guest session - update its current state.
@@ -2356 +2366 @@
  * @retval  VERR_NOT_FOUND if the object ID was not found.
  * @param   idObject        Object ID to unregister.
+ *
+ * @note    Takes the write lock.
  */
 int GuestSession::i_objectUnregister(uint32_t idObject)
@@ -2469 +2481 @@
  * @param   prcGuest            Where to return the guest error when VERR_GSTCTL_GUEST_ERROR
  *                              was returned. Optional.
- * @note    Takes the write lock.
+ * @note    Takes the read lock.
  */
 int GuestSession::i_pathRename(const Utf8Str &strSource, const Utf8Str &strDest, uint32_t uFlags, int *prcGuest)
@@ -2478 +2490 @@
                      strSource.c_str(), strDest.c_str(), uFlags));
 
-    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
 
     GuestWaitEvent *pEvent = NULL;
@@ -2495 +2507 @@
     HGCMSvcSetU32(&paParms[i++], uFlags);
 
-    alock.release(); /* Drop write lock before sending. */
+    alock.release(); /* Drop lock before sending. */
 
     vrc = i_sendMessage(HOST_MSG_PATH_RENAME, i, paParms);
@@ -2520 +2532 @@
  *                              Any other return code indicates some host side error.
  *
- * @note    Takes the write lock.
+ * @note    Takes the read lock.
  */
 int GuestSession::i_pathUserDocuments(Utf8Str &strPath, int *prcGuest)
 {
-    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
 
     /** @todo Cache the user's document path? */
@@ -2538 +2550 @@
     HGCMSvcSetU32(&paParms[i++], pEvent->ContextID());
 
-    alock.release(); /* Drop write lock before sending. */
+    alock.release(); /* Drop lock before sending. */
 
     vrc = i_sendMessage(HOST_MSG_PATH_USER_DOCUMENTS, i, paParms);
@@ -2572 +2584 @@
  *                              Any other return code indicates some host side error.
  *
- * @note    Takes the write lock.
+ * @note    Takes the read lock.
  */
 int GuestSession::i_pathUserHome(Utf8Str &strPath, int *prcGuest)
 {
-    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
 
     /** @todo Cache the user's home path? */
@@ -2590 +2602 @@
     HGCMSvcSetU32(&paParms[i++], pEvent->ContextID());
 
-    alock.release(); /* Drop write lock before sending. */
+    alock.release(); /* Drop lock before sending. */
 
     vrc = i_sendMessage(HOST_MSG_PATH_USER_HOME, i, paParms);
@@ -2957 +2969 @@
  *                              Any other return code indicates some host side error.
  *
- * @note    Takes the write lock.
+ * @note    Takes the read lock.
  */
 int GuestSession::i_shutdown(uint32_t fFlags, int *prcGuest)
 {
-    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
 
     AssertPtrReturn(mParent, VERR_INVALID_POINTER);
@@ -2980 +2992 @@
     HGCMSvcSetU32(&paParms[i++], fFlags);
 
-    alock.release(); /* Drop write lock before sending. */
+    alock.release(); /* Drop lock before sending. */
 
     int rcGuest = VERR_IPE_UNINITIALIZED_STATUS;