[SCM] Samba Shared Repository - branch master updated - release-4-0-0alpha7-1586-g8a60c26

[Derrell Lipman]

The branch, master has been updated
       via  8a60c26c7cb788fe181fb8db10e454b96dda23a9 (commit)
      from  3627ceb5e25cdecd1a8113a5028cc898a1424349 (commit)

http://gitweb.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit 8a60c26c7cb788fe181fb8db10e454b96dda23a9
Author: Derrell Lipman <derrell at dworkin.(none)>
Date:   Tue May 12 21:22:23 2009 -0400

    Fix broken smb_thread_once function
    
    - We can't set *ponce=true before running the function because although other
      threads wouldn't re-run the initialization function, they could potentially
      proceed beyond the initialization point while the first thread was still
      running the initialization function. If a second thread gets to an
      SMB_THREAD_ONCE() call while one with the same ponce is running, we need to
      ensure that it enters smb_thread_once() to await the mutex and then recheck
      whether *ponce is set or not.  My original comment about other "once"
      functions possibly being called from within this "once" function is
      irrelevant since those other ones would have their own unique ponce.
    
    Derrell

-----------------------------------------------------------------------

Summary of changes:
 lib/util/smb_threads.c |   22 +++-------------------
 1 files changed, 3 insertions(+), 19 deletions(-)


Changeset truncated at 500 lines:

diff --git a/lib/util/smb_threads.c b/lib/util/smb_threads.c
index 0407976..6f84a2e 100644
--- a/lib/util/smb_threads.c
+++ b/lib/util/smb_threads.c
@@ -108,29 +108,19 @@ int smb_thread_set_functions(const struct smb_thread_functions *tf)
 int smb_thread_once(smb_thread_once_t *ponce, void (*init_fn)(void))
 {
         int ret;
-        bool need_func_call;
 
         /* Lock our "once" mutex in order to test and initialize ponce */
 	if ((ret = SMB_THREAD_LOCK(once_mutex, SMB_THREAD_LOCK)) != 0) {
                 smb_panic("error locking 'once'");
 	}
 
-        /* Store whether we're going to need to issue the function call */
-        need_func_call = ! *ponce;
-
         /*
          * See if another thread got here after we tested it initially but
          * before we got our lock.
          */
-        if (need_func_call) {
-                /*
-                 * Nope, we still need to issue the call. Set the "once"
-                 * variable to true now so we can unlock the mutex. (We don't
-                 * want to leave it locked during the call to the
-                 * initialization function in case there's yet another "once"
-                 * function needed to be called from therein.)
-                 */
-                *ponce = true;
+        if (! *ponce) {
+                /* Nope, we need to run the initialization function */
+                (*init_fn)();
         }
 
         /* Unlock the mutex */
@@ -138,12 +128,6 @@ int smb_thread_once(smb_thread_once_t *ponce, void (*init_fn)(void))
                 smb_panic("error unlocking 'once'");
 	}
 
-        /* Finally, if we need to call the user-provided function, ... */
-        if (need_func_call) {
-                /* ... then do so now. */
-                (*init_fn)();
-        }
-
 	return 0;
 }
 


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