[haiku-commits] r34074 - haiku/trunk/src/system/kernel

From: axeld@xxxxxxxxxxxxxxxx
To: haiku-commits@xxxxxxxxxxxxx
Date: Mon, 16 Nov 2009 14:08:36 +0100 (CET)
Author: axeld
Date: 2009-11-16 14:08:36 +0100 (Mon, 16 Nov 2009)
New Revision: 34074
Changeset: http://dev.haiku-os.org/changeset/34074/haiku
Ticket: http://dev.haiku-os.org/ticket/4917

Modified:
   haiku/trunk/src/system/kernel/sem.cpp
Log:
* Change get_next_sem_info() to be index based, not ID based - the semaphore IDs
  aren't monotonically increasing which this code was assuming. This fixes bug
  #4917.


Modified: haiku/trunk/src/system/kernel/sem.cpp
===================================================================
--- haiku/trunk/src/system/kernel/sem.cpp       2009-11-16 11:57:19 UTC (rev 
34073)
+++ haiku/trunk/src/system/kernel/sem.cpp       2009-11-16 13:08:36 UTC (rev 
34074)
@@ -1123,47 +1123,39 @@
        if (team == NULL)
                return B_BAD_TEAM_ID;
 
-       int32 id = *_cookie;
-       sem_entry* sem = NULL;
-
-       if (id != 0) {
-               // shortcut to the first entry
-               sem = &sSems[id % sMaxSems];
-               GRAB_SEM_LOCK(*sem);
-
-               // Check if the semaphore got deleted or reused in the mean time
-               if (sem->id != id)
-                       sem = NULL;
-
-               RELEASE_SEM_LOCK(*sem);
-       }
-       if (sem == NULL)
-               sem = (sem_entry*)list_get_first_item(&team->sem_list);
-
+       // TODO: find a way to iterate the list that is more reliable
+       sem_entry* sem = (sem_entry*)list_get_first_item(&team->sem_list);
+       int32 newIndex = *_cookie;
+       int32 index = 0;
        bool found = false;
 
        while (!found) {
                // find the next entry to be returned
-               while (sem != NULL && id >= sem->id)
+               while (sem != NULL && index < newIndex) {
                        sem = (sem_entry*)list_get_next_item(&team->sem_list, 
sem);
+                       index++;
+               }
 
                if (sem == NULL)
                        return B_BAD_VALUE;
 
                GRAB_SEM_LOCK(*sem);
+
                if (sem->id != -1 && sem->u.used.owner == team) {
                        // found one!
                        fill_sem_info(sem, info, size);
-                       id = sem->id;
+                       newIndex = index + 1;
                        found = true;
-               }
+               } else
+                       newIndex++;
+
                RELEASE_SEM_LOCK(*sem);
        }
 
        if (!found)
                return B_BAD_VALUE;
 
-       *_cookie = id;
+       *_cookie = newIndex;
        return B_OK;
 }
[haiku-commits] r34074 - haiku/trunk/src/system/kernel

Other related posts:
