xnu-7195.50.7.100.1.tar.gz

[apple/xnu.git] / osfmk / kern / queue.h

diff --git a/osfmk/kern/queue.h b/osfmk/kern/queue.h
index 68032cbe7f7414bd19c7ab467bc16faeaf6b881b..ac758f79e809bdd6cd77d5b7f1927ced8b1ac041 100644 (file)
--- a/osfmk/kern/queue.h
+++ b/osfmk/kern/queue.h
@@ -360,14 +360,7 @@ static __inline__ void
 remque(
        queue_entry_t elt)
 {
-       queue_entry_t   next_elt, prev_elt;
-
-       __QUEUE_ELT_VALIDATE(elt);
-       next_elt = elt->next;
-       prev_elt = elt->prev; /* next_elt may equal prev_elt (and the queue head) if elt was the only element */
-       next_elt->prev = prev_elt;
-       prev_elt->next = next_elt;
-       __DEQUEUE_ELT_CLEANUP(elt);
+       remqueue(elt);
 }
 
 /*
@@ -572,8 +565,34 @@ re_queue_tail(queue_t que, queue_entry_t elt)
        _tmp_element; \
 })
 
+/* Peek at the next element, or return NULL if the next element is head (indicating queue_end) */
+#define qe_queue_next(head, element, type, field) ({ \
+       queue_entry_t _tmp_entry = queue_next(&(element)->field); \
+       type *_tmp_element = (type*) NULL; \
+       if (_tmp_entry != (queue_entry_t) head) \
+               _tmp_element = qe_element(_tmp_entry, type, field); \
+       _tmp_element; \
+})
+
+/* Peek at the prev element, or return NULL if the prev element is head (indicating queue_end) */
+#define qe_queue_prev(head, element, type, field) ({ \
+       queue_entry_t _tmp_entry = queue_prev(&(element)->field); \
+       type *_tmp_element = (type*) NULL; \
+       if (_tmp_entry != (queue_entry_t) head) \
+               _tmp_element = qe_element(_tmp_entry, type, field); \
+       _tmp_element; \
+})
+
 #endif /* XNU_KERNEL_PRIVATE */
 
+/*
+ *     Macro:          QUEUE_HEAD_INITIALIZER()
+ *     Function:
+ *             Static queue head initializer
+ */
+#define QUEUE_HEAD_INITIALIZER(name) \
+       { &name, &name }
+
 /*
  *     Macro:          queue_init
  *     Function: