flow engine: no longer allow FlowRequeue to be called with the same src and dst queue.

src/flow-queue.c

@@ -136,49 +136,41 @@ Flow *FlowDequeue (FlowQueue *q) {
  *  \brief Transfer a flow from one queue to another
  *
  *  \param f the flow to be transfered
- *  \param srcq the source queue, where the flow will be removed. The param may
- *              be NULL.
+ *  \param srcq the source queue, where the flow will be removed.
  *  \param dstq the dest queue where the flow will be placed
  *
+ *  \note srcq and dstq must be different queues.
  */
 void FlowRequeue(Flow *f, FlowQueue *srcq, FlowQueue *dstq)
 {
 #ifdef DEBUG
-    BUG_ON(dstq == NULL);
+    BUG_ON(srcq == NULL || dstq == NULL || srcq == dstq);
 #endif /* DEBUG */
 
-    if (srcq != NULL) {
-        SCMutexLock(&srcq->mutex_q);
+    SCMutexLock(&srcq->mutex_q);
 
-        /* remove from old queue */
-        if (srcq->top == f)
-            srcq->top = f->lnext;       /* remove from queue top */
-        if (srcq->bot == f)
-            srcq->bot = f->lprev;       /* remove from queue bot */
-        if (f->lprev != NULL)
-            f->lprev->lnext = f->lnext; /* remove from flow prev */
-        if (f->lnext != NULL)
-            f->lnext->lprev = f->lprev; /* remove from flow next */
+    /* remove from old queue */
+    if (srcq->top == f)
+        srcq->top = f->lnext;       /* remove from queue top */
+    if (srcq->bot == f)
+        srcq->bot = f->lprev;       /* remove from queue bot */
+    if (f->lprev != NULL)
+        f->lprev->lnext = f->lnext; /* remove from flow prev */
+    if (f->lnext != NULL)
+        f->lnext->lprev = f->lprev; /* remove from flow next */
 
 #ifdef DEBUG
-        BUG_ON(srcq->len == 0);
+    BUG_ON(srcq->len == 0);
 #endif
-        if (srcq->len > 0)
-            srcq->len--; /* adjust len */
+    if (srcq->len > 0)
+        srcq->len--; /* adjust len */
 
-        f->lnext = NULL;
-        f->lprev = NULL;
+    f->lnext = NULL;
+    f->lprev = NULL;
 
-        /* don't unlock if src and dst are the same */
-        if (srcq != dstq) {
-            SCMutexUnlock(&srcq->mutex_q);
-        }
-    }
+    SCMutexUnlock(&srcq->mutex_q);
 
-    /* now put it in dst */
-    if (srcq != dstq) {
-        SCMutexLock(&dstq->mutex_q);
-    }
+    SCMutexLock(&dstq->mutex_q);
 
     /* add to new queue (append) */
     f->lprev = dstq->bot;