--- sem.c.old	Sun Feb 25 10:50:55 2001
+++ sem.c	Sun Feb 25 10:51:19 2001
@@ -250,23 +250,23 @@
 		curr = sma->sem_base + sop->sem_num;
 		sem_op = sop->sem_op;
 
-		if (!sem_op && curr->semval)
+		result = curr->semval;
+		if (!sem_op && result)
 			goto would_block;
+		result += sem_op;
+		if (result < 0)
+			goto would_block;
+		if (result > SEMVMX)
+			goto out_of_range;
 
 		curr->sempid = (curr->sempid << 16) | pid;
-		curr->semval += sem_op;
+		curr->semval = result;
 		if (sop->sem_flg & SEM_UNDO)
 			un->semadj[sop->sem_num] -= sem_op;
-
-		if (curr->semval < 0)
-			goto would_block;
-		if (curr->semval > SEMVMX)
-			goto out_of_range;
 	}
 
 	if (do_undo)
 	{
-		sop--;
 		result = 0;
 		goto undo;
 	}
@@ -285,6 +285,7 @@
 		result = 1;
 
 undo:
+	sop--;
 	while (sop >= sops) {
 		curr = sma->sem_base + sop->sem_num;
 		curr->semval -= sop->sem_op;
@@ -305,7 +306,9 @@
 {
 	int error;
 	struct sem_queue * q;
+	int do_retry = 0;
 
+retry:
 	for (q = sma->sem_pending; q; q = q->next) {
 			
 		if (q->status == 1)
@@ -323,10 +326,17 @@
 				q->status = 1;
 				return;
 			}
-			q->status = error;
 			remove_from_queue(sma,q);
+			wmb();
+			q->status = error;
+			/* FIXME: retry only required if an increase was
+			 * executed
+			 */
+			do_retry = 1;
 		}
 	}
+	if (do_retry)
+		goto retry;
 }
 
 /* The following counts are associated to each semaphore:
@@ -919,7 +929,13 @@
 		sem_unlock(semid);
 
 		schedule();
-
+		if (queue.status == 0) {
+			error = 0;
+			if (queue.prev)
+				BUG();
+			current->semsleeping = NULL;
+			goto out_free;
+		}
 		tmp = sem_lock(semid);
 		if(tmp==NULL) {
 			if(queue.prev != NULL)