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xnu-4570.51.1.tar.gz
[apple/xnu.git] / osfmk / kern / queue.h
index 836b55293137ffbfd6b9d538cc9ca680c84d5963..1cdcd4f1bc6cb716f8f45d0435b5753db42b0f74 100644 (file)
 #include <mach/mach_types.h>
 #include <kern/macro_help.h>
 
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
 /*
- *     Queue of abstract objects.  Queue is maintained
- *     within that object.
+ * Queue Management APIs
+ *
+ * There are currently two subtly different methods of maintining
+ * a queue of objects. Both APIs are contained in this file, and
+ * unfortunately overlap.
+ * (there is also a third way maintained in bsd/sys/queue.h)
+ *
+ * Both methods use a common queue head and linkage pattern:
+ *     The head of a queue is declared as:
+ *             queue_head_t q_head;
+ *
+ *     Elements in this queue are chained together using
+ *     struct queue_entry objects embedded within a structure:
+ *             struct some_data {
+ *                     int field1;
+ *                     int field2;
+ *                     ...
+ *                     queue_chain_t link;
+ *                     ...
+ *                     int last_field;
+ *             };
+ *     struct some_data is referred to as the queue "element."
+ *     (note that queue_chain_t is typedef'd to struct queue_entry)
+ *
+ * IMPORTANT: The two queue iteration methods described below are not
+ *            compatible with one another. You must choose one and be careful
+ *            to use only the supported APIs for that method.
  *
- *     Supports fast removal from within the queue.
+ * Method 1: chaining of queue_chain_t (linkage chains)
+ *     This method uses the next and prev pointers of the struct queue_entry
+ *     linkage object embedded in a queue element to point to the next or
+ *     previous queue_entry structure in the chain. The head of the queue
+ *     (the queue_head_t object) will point to the first and last
+ *     struct queue_entry object, and both the next and prev pointer will
+ *     point back to the head if the queue is empty.
  *
- *     How to declare a queue of elements of type "foo_t":
- *             In the "*foo_t" type, you must have a field of
- *             type "queue_chain_t" to hold together this queue.
- *             There may be more than one chain through a
- *             "foo_t", for use by different queues.
+ *     This method is the most flexible method of chaining objects together
+ *     as it allows multiple chains through a given object, by embedding
+ *     multiple queue_chain_t objects in the structure, while simultaneously
+ *     providing fast removal and insertion into the queue using only
+ *     struct queue_entry object pointers.
  *
- *             Declare the queue as a "queue_t" type.
+ *     ++ Valid APIs for this style queue ++
+ *     -------------------------------------
+ *             [C] queue_init
+ *             [C] queue_first
+ *             [C] queue_next
+ *             [C] queue_last
+ *             [C] queue_prev
+ *             [C] queue_end
+ *             [C] queue_empty
  *
- *             Elements of the queue (of type "foo_t", that is)
- *             are referred to by reference, and cast to type
- *             "queue_entry_t" within this module.
+ *             [1] enqueue
+ *             [1] dequeue
+ *             [1] enqueue_head
+ *             [1] enqueue_tail
+ *             [1] dequeue_head
+ *             [1] dequeue_tail
+ *             [1] remqueue
+ *             [1] insque
+ *             [1] remque
+ *             [1] re_queue_head
+ *             [1] re_queue_tail
+ *             [1] movqueue
+ *             [1] qe_element
+ *             [1] qe_foreach
+ *             [1] qe_foreach_safe
+ *             [1] qe_foreach_element
+ *             [1] qe_foreach_element_safe
+ *
+ * Method 2: chaining of elements (element chains)
+ *     This method uses the next and prev pointers of the struct queue_entry
+ *     linkage object embedded in a queue element to point to the next or
+ *     previous queue element (not another queue_entry). The head of the
+ *     queue will point to the first and last queue element (struct some_data
+ *     from the above example) NOT the embedded queue_entry structure. The
+ *     first queue element will have a prev pointer that points to the
+ *     queue_head_t, and the last queue element will have a next pointer
+ *     that points to the queue_head_t.
+ *
+ *     This method requires knowledge of the queue_head_t of the queue on
+ *     which an element resides in order to remove the element. Iterating
+ *     through the elements of the queue is also more cumbersome because
+ *     a check against the head pointer plus a cast then offset operation
+ *     must be performed at each step of the iteration.
+ *
+ *     ++ Valid APIs for this style queue ++
+ *     -------------------------------------
+ *             [C] queue_init
+ *             [C] queue_first
+ *             [C] queue_next
+ *             [C] queue_last
+ *             [C] queue_prev
+ *             [C] queue_end
+ *             [C] queue_empty
+ *
+ *             [2] queue_enter
+ *             [2] queue_enter_first
+ *             [2] queue_insert_before
+ *             [2] queue_insert_after
+ *             [2] queue_field
+ *             [2] queue_remove
+ *             [2] queue_remove_first
+ *             [2] queue_remove_last
+ *             [2] queue_assign
+ *             [2] queue_new_head
+ *             [2] queue_iterate
+ *
+ * Legend:
+ *     [C] -> API common to both methods
+ *     [1] -> API used only in method 1 (linkage chains)
+ *     [2] -> API used only in method 2 (element chains)
  */
 
 /*
 struct queue_entry {
        struct queue_entry      *next;          /* next element */
        struct queue_entry      *prev;          /* previous element */
+
+#if __arm__ && (__BIGGEST_ALIGNMENT__ > 4)
+/* For the newer ARMv7k ABI where 64-bit types are 64-bit aligned, but pointers
+ * are 32-bit:
+ * Since this type is so often cast to various 64-bit aligned types
+ * aligning it to 64-bits will avoid -wcast-align without needing
+ * to disable it entirely. The impact on memory footprint should be 
+ * negligible.
+ */
+} __attribute__ ((aligned (8)));
+#else
 };
+#endif
 
 typedef struct queue_entry     *queue_t;
 typedef        struct queue_entry      queue_head_t;
@@ -112,52 +224,34 @@ typedef   struct queue_entry      *queue_entry_t;
 #define enqueue(queue,elt)     enqueue_tail(queue, elt)
 #define        dequeue(queue)          dequeue_head(queue)
 
-#if    !defined(__GNUC__)
-
-#include <sys/cdefs.h>
-__BEGIN_DECLS
-
-/* Enqueue element to head of queue */
-extern void            enqueue_head(
-                               queue_t         que,
-                               queue_entry_t   elt);
-
-/* Enqueue element to tail of queue */
-extern void            enqueue_tail(
-                               queue_t         que,
-                               queue_entry_t   elt);
-
-/* Dequeue element from head of queue */
-extern queue_entry_t   dequeue_head(
-                               queue_t que);
-
-/* Dequeue element from tail of queue */
-extern queue_entry_t   dequeue_tail(
-                               queue_t que);
-
-/* Dequeue element */
-extern void            remqueue(
-                               queue_entry_t   elt);
-
-/* Enqueue element after a particular elem */
-extern void            insque(
-                               queue_entry_t   entry,
-                               queue_entry_t   pred);
-
-/* Dequeue element */
-extern void            remque(
-                               queue_entry_t elt);
-
-__END_DECLS
-
-#else  /* !__GNUC__ */
-
 #ifdef XNU_KERNEL_PRIVATE
-#define __DEQUEUE_ELT_CLEANUP(elt) do { \
-               (elt)->next = (queue_entry_t) 0; \
-               (elt)->prev = (queue_entry_t) 0; \
-       } while (0)
+#include <kern/debug.h>
+#include <mach/branch_predicates.h>
+static inline void __QUEUE_ELT_VALIDATE(queue_entry_t elt) {
+       queue_entry_t   elt_next, elt_prev;
+       
+       if (__improbable(elt == (queue_entry_t)0)) {
+               panic("Invalid queue element %p", elt);
+       }
+       
+       elt_next = elt->next;
+       elt_prev = elt->prev;
+       
+       if (__improbable(elt_next == (queue_entry_t)0 || elt_prev == (queue_entry_t)0)) {
+               panic("Invalid queue element pointers for %p: next %p prev %p", elt, elt_next, elt_prev);
+       }
+       if (__improbable(elt_next->prev != elt || elt_prev->next != elt)) {
+               panic("Invalid queue element linkage for %p: next %p next->prev %p prev %p prev->next %p", 
+                         elt, elt_next, elt_next->prev, elt_prev, elt_prev->next);
+       }
+}
+
+static inline void __DEQUEUE_ELT_CLEANUP(queue_entry_t elt) {
+       (elt)->next = (queue_entry_t) 0;
+       (elt)->prev = (queue_entry_t) 0;
+}
 #else
+#define __QUEUE_ELT_VALIDATE(elt) do { } while (0)
 #define __DEQUEUE_ELT_CLEANUP(elt) do { } while(0)
 #endif /* !XNU_KERNEL_PRIVATE */
 
@@ -166,9 +260,13 @@ enqueue_head(
        queue_t         que,
        queue_entry_t   elt)
 {
-       elt->next = que->next;
+       queue_entry_t   old_head;
+
+       __QUEUE_ELT_VALIDATE((queue_entry_t)que);
+       old_head = que->next;
+       elt->next = old_head;
        elt->prev = que;
-       elt->next->prev = elt;
+       old_head->prev = elt;
        que->next = elt;
 }
 
@@ -177,9 +275,13 @@ enqueue_tail(
                queue_t         que,
                queue_entry_t   elt)
 {
+       queue_entry_t   old_tail;
+
+       __QUEUE_ELT_VALIDATE((queue_entry_t)que);
+       old_tail = que->prev;
        elt->next = que;
-       elt->prev = que->prev;
-       elt->prev->next = elt;
+       elt->prev = old_tail;
+       old_tail->next = elt;
        que->prev = elt;
 }
 
@@ -187,12 +289,15 @@ static __inline__ queue_entry_t
 dequeue_head(
        queue_t que)
 {
-       register queue_entry_t  elt = (queue_entry_t) 0;
+       queue_entry_t   elt = (queue_entry_t) 0;
+       queue_entry_t   new_head;
 
        if (que->next != que) {
                elt = que->next;
-               elt->next->prev = que;
-               que->next = elt->next;
+               __QUEUE_ELT_VALIDATE(elt);
+               new_head = elt->next; /* new_head may point to que if elt was the only element */
+               new_head->prev = que;
+               que->next = new_head;
                __DEQUEUE_ELT_CLEANUP(elt);
        }
 
@@ -203,12 +308,15 @@ static __inline__ queue_entry_t
 dequeue_tail(
        queue_t que)
 {
-       register queue_entry_t  elt = (queue_entry_t) 0;
+       queue_entry_t   elt = (queue_entry_t) 0;
+       queue_entry_t   new_tail;
 
        if (que->prev != que) {
                elt = que->prev;
-               elt->prev->next = que;
-               que->prev = elt->prev;
+               __QUEUE_ELT_VALIDATE(elt);
+               new_tail = elt->prev; /* new_tail may point to queue if elt was the only element */
+               new_tail->next = que;
+               que->prev = new_tail;
                __DEQUEUE_ELT_CLEANUP(elt);
        }
 
@@ -219,8 +327,13 @@ static __inline__ void
 remqueue(
        queue_entry_t   elt)
 {
-       elt->next->prev = elt->prev;
-       elt->prev->next = elt->next;
+       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);
 }
 
@@ -229,22 +342,234 @@ insque(
        queue_entry_t   entry,
        queue_entry_t   pred)
 {
-       entry->next = pred->next;
+       queue_entry_t   successor;
+
+       __QUEUE_ELT_VALIDATE(pred);
+       successor = pred->next;
+       entry->next = successor;
        entry->prev = pred;
-       (pred->next)->prev = entry;
+       successor->prev = entry;
        pred->next = entry;
 }
 
 static __inline__ void
 remque(
-       register queue_entry_t elt)
+       queue_entry_t elt)
 {
-       (elt->next)->prev = elt->prev;
-       (elt->prev)->next = elt->next;
+       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);
 }
 
-#endif /* !__GNUC__ */
+/*
+ *     Function:       re_queue_head
+ *     Parameters:
+ *             queue_t que       : queue onto which elt will be pre-pended
+ *             queue_entry_t elt : element to re-queue
+ *     Description:
+ *             Remove elt from its current queue and put it onto the
+ *             head of a new queue
+ *     Note:
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+static __inline__ void
+re_queue_head(queue_t que, queue_entry_t elt)
+{
+       queue_entry_t   n_elt, p_elt;
+
+       __QUEUE_ELT_VALIDATE(elt);
+       __QUEUE_ELT_VALIDATE((queue_entry_t)que);
+
+       /* remqueue */
+       n_elt = elt->next;
+       p_elt = elt->prev; /* next_elt may equal prev_elt (and the queue head) if elt was the only element */
+       n_elt->prev = p_elt;
+       p_elt->next = n_elt;
+
+       /* enqueue_head */
+       n_elt = que->next;
+       elt->next = n_elt;
+       elt->prev = que;
+       n_elt->prev = elt;
+       que->next = elt;
+}
+
+/*
+ *     Function:       re_queue_tail
+ *     Parameters:
+ *             queue_t que       : queue onto which elt will be appended
+ *             queue_entry_t elt : element to re-queue
+ *     Description:
+ *             Remove elt from its current queue and put it onto the
+ *             end of a new queue
+ *     Note:
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+static __inline__ void
+re_queue_tail(queue_t que, queue_entry_t elt)
+{
+       queue_entry_t   n_elt, p_elt;
+
+       __QUEUE_ELT_VALIDATE(elt);
+       __QUEUE_ELT_VALIDATE((queue_entry_t)que);
+
+       /* remqueue */
+       n_elt = elt->next;
+       p_elt = elt->prev; /* next_elt may equal prev_elt (and the queue head) if elt was the only element */
+       n_elt->prev = p_elt;
+       p_elt->next = n_elt;
+
+       /* enqueue_tail */
+       p_elt = que->prev;
+       elt->next = que;
+       elt->prev = p_elt;
+       p_elt->next = elt;
+       que->prev = elt;
+}
+
+/*
+ *     Macro:          qe_element
+ *     Function:
+ *             Convert a queue_entry_t to a queue element pointer.
+ *             Get a pointer to the user-defined element containing
+ *             a given queue_entry_t
+ *     Header:
+ *             <type> * qe_element(queue_entry_t qe, <type>, field)
+ *                     qe      - queue entry to convert
+ *                     <type>  - what's in the queue (e.g., struct some_data)
+ *                     <field> - is the chain field in <type>
+ *     Note:
+ *             Do not use pointer types for <type>
+ */
+#define        qe_element(qe, type, field) \
+       ((type *)((void *)((char *)(qe) - __offsetof(type, field))))
+
+/*
+ *     Macro:          qe_foreach
+ *     Function:
+ *             Iterate over each queue_entry_t structure.
+ *             Generates a 'for' loop, setting 'qe' to
+ *             each queue_entry_t in the queue.
+ *     Header:
+ *             qe_foreach(queue_entry_t qe, queue_t head)
+ *                     qe   - iteration variable
+ *                     head - pointer to queue_head_t (head of queue)
+ *     Note:
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+#define qe_foreach(qe, head) \
+       for (qe = (head)->next; qe != (head); qe = (qe)->next)
+
+/*
+ *     Macro:          qe_foreach_safe
+ *     Function:
+ *             Safely iterate over each queue_entry_t structure.
+ *
+ *             Use this iterator macro if you plan to remove the
+ *             queue_entry_t, qe, from the queue during the
+ *             iteration.
+ *     Header:
+ *             qe_foreach_safe(queue_entry_t qe, queue_t head)
+ *                     qe   - iteration variable
+ *                     head - pointer to queue_head_t (head of queue)
+ *     Note:
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+#define qe_foreach_safe(qe, head) \
+       for (queue_entry_t _ne = ((head)->next)->next, \
+                __ ## qe ## _unused_shadow __unused = (qe = (head)->next); \
+            qe != (head); \
+            qe = _ne, _ne = (qe)->next)
+
+/*
+ *     Macro:          qe_foreach_element
+ *     Function:
+ *             Iterate over each _element_ in a queue
+ *             where each queue_entry_t points to another
+ *             queue_entry_t, i.e., managed by the [de|en]queue_head/
+ *             [de|en]queue_tail / remqueue / etc. function.
+ *     Header:
+ *             qe_foreach_element(<type> *elt, queue_t head, <field>)
+ *                     elt     - iteration variable
+ *                     <type>  - what's in the queue (e.g., struct some_data)
+ *                     <field> - is the chain field in <type>
+ *     Note:
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+#define qe_foreach_element(elt, head, field) \
+       for (elt = qe_element((head)->next, typeof(*(elt)), field); \
+            &((elt)->field) != (head); \
+            elt = qe_element((elt)->field.next, typeof(*(elt)), field))
+
+/*
+ *     Macro:          qe_foreach_element_safe
+ *     Function:
+ *             Safely iterate over each _element_ in a queue
+ *             where each queue_entry_t points to another
+ *             queue_entry_t, i.e., managed by the [de|en]queue_head/
+ *             [de|en]queue_tail / remqueue / etc. function.
+ *
+ *             Use this iterator macro if you plan to remove the
+ *             element, elt, from the queue during the iteration.
+ *     Header:
+ *             qe_foreach_element_safe(<type> *elt, queue_t head, <field>)
+ *                     elt     - iteration variable
+ *                     <type>  - what's in the queue (e.g., struct some_data)
+ *                     <field> - is the chain field in <type>
+ *     Note:
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+#define qe_foreach_element_safe(elt, head, field) \
+       for (typeof(*(elt)) *_nelt = qe_element(((head)->next)->next, typeof(*(elt)), field), \
+            *__ ## elt ## _unused_shadow __unused = \
+                (elt = qe_element((head)->next, typeof(*(elt)), field)); \
+            &((elt)->field) != (head); \
+            elt = _nelt, _nelt = qe_element((elt)->field.next, typeof(*(elt)), field)) \
+
+#ifdef XNU_KERNEL_PRIVATE
+
+/* Dequeue an element from head, or return NULL if the queue is empty */
+#define qe_dequeue_head(head, type, field) ({ \
+       queue_entry_t _tmp_entry = dequeue_head((head)); \
+       type *_tmp_element = (type*) NULL; \
+       if (_tmp_entry != (queue_entry_t) NULL) \
+               _tmp_element = qe_element(_tmp_entry, type, field); \
+       _tmp_element; \
+})
+
+/* Dequeue an element from tail, or return NULL if the queue is empty */
+#define qe_dequeue_tail(head, type, field) ({ \
+       queue_entry_t _tmp_entry = dequeue_tail((head)); \
+       type *_tmp_element = (type*) NULL; \
+       if (_tmp_entry != (queue_entry_t) NULL) \
+               _tmp_element = qe_element(_tmp_entry, type, field); \
+       _tmp_element; \
+})
+
+/* Peek at the first element, or return NULL if the queue is empty */
+#define qe_queue_first(head, type, field) ({ \
+       queue_entry_t _tmp_entry = queue_first((head)); \
+       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 last element, or return NULL if the queue is empty */
+#define qe_queue_last(head, type, field) ({ \
+       queue_entry_t _tmp_entry = queue_last((head)); \
+       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_init
@@ -260,6 +585,28 @@ MACRO_BEGIN                \
        (q)->prev = (q);\
 MACRO_END
 
+/*
+ *     Macro:          queue_head_init
+ *     Function:
+ *             Initialize the given queue head
+ *     Header:
+ *             void queue_head_init(q)
+ *                     queue_head_t    q;      \* MODIFIED *\
+ */
+#define queue_head_init(q) \
+       queue_init(&(q))
+
+/*
+ *     Macro:          queue_chain_init
+ *     Function:
+ *             Initialize the given queue chain element
+ *     Header:
+ *             void queue_chain_init(q)
+ *                     queue_chain_t   q;      \* MODIFIED *\
+ */
+#define queue_chain_init(q) \
+       queue_init(&(q))
+
 /*
  *     Macro:          queue_first
  *     Function:
@@ -322,6 +669,47 @@ MACRO_END
  */
 #define        queue_empty(q)          queue_end((q), queue_first(q))
 
+/*
+ *     Function:       movqueue
+ *     Parameters:
+ *             queue_t _old : head of a queue whose items will be moved
+ *             queue_t _new : new queue head onto which items will be moved
+ *     Description:
+ *             Rebase queue items in _old onto _new then re-initialize
+ *             the _old object to an empty queue.
+ *             Equivalent to the queue_new_head Method 2 macro
+ *     Note:
+ *             Similar to the queue_new_head macro, this macros is intented
+ *             to function as an initializer method for '_new' and thus may
+ *             leak any list items that happen to be on the '_new' list.
+ *             This should only be used with Method 1 queue iteration (linkage chains)
+ */
+static __inline__ void
+movqueue(queue_t _old, queue_t _new)
+{
+       queue_entry_t   next_elt, prev_elt;
+
+       __QUEUE_ELT_VALIDATE((queue_entry_t)_old);
+
+       if (queue_empty(_old)) {
+               queue_init(_new);
+               return;
+       }
+
+       /*
+        * move the queue at _old to _new
+        * and re-initialize _old
+        */
+       next_elt = _old->next;
+       prev_elt = _old->prev;
+
+       _new->next = next_elt;
+       _new->prev = prev_elt;
+       next_elt->prev = _new;
+       prev_elt->next = _new;
+
+       queue_init(_old);
+}
 
 /*----------------------------------------------------------------*/
 /*
@@ -340,17 +728,20 @@ MACRO_END
  *                     <type> elt;
  *                     <type> is what's in our queue
  *                     <field> is the chain field in (*<type>)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define queue_enter(head, elt, type, field)                    \
 MACRO_BEGIN                                                    \
-       register queue_entry_t __prev;                          \
+       queue_entry_t __prev;                                   \
                                                                \
        __prev = (head)->prev;                                  \
        if ((head) == __prev) {                                 \
                (head)->next = (queue_entry_t) (elt);           \
        }                                                       \
        else {                                                  \
-               ((type)__prev)->field.next = (queue_entry_t)(elt);\
+               ((type)(void *)__prev)->field.next =            \
+                       (queue_entry_t)(elt);                   \
        }                                                       \
        (elt)->field.prev = __prev;                             \
        (elt)->field.next = head;                               \
@@ -367,17 +758,20 @@ MACRO_END
  *                     <type> elt;
  *                     <type> is what's in our queue
  *                     <field> is the chain field in (*<type>)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define queue_enter_first(head, elt, type, field)              \
 MACRO_BEGIN                                                    \
-       register queue_entry_t __next;                          \
+       queue_entry_t __next;                                   \
                                                                \
        __next = (head)->next;                                  \
        if ((head) == __next) {                                 \
                (head)->prev = (queue_entry_t) (elt);           \
        }                                                       \
        else {                                                  \
-               ((type)__next)->field.prev = (queue_entry_t)(elt);\
+               ((type)(void *)__next)->field.prev =            \
+                       (queue_entry_t)(elt);                   \
        }                                                       \
        (elt)->field.next = __next;                             \
        (elt)->field.prev = head;                               \
@@ -395,10 +789,12 @@ MACRO_END
  *                     <type> cur;
  *                     <type> is what's in our queue
  *                     <field> is the chain field in (*<type>)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define queue_insert_before(head, elt, cur, type, field)               \
 MACRO_BEGIN                                                            \
-       register queue_entry_t __prev;                                  \
+       queue_entry_t __prev;                                           \
                                                                        \
        if ((head) == (queue_entry_t)(cur)) {                           \
                (elt)->field.next = (head);                             \
@@ -407,7 +803,8 @@ MACRO_BEGIN                                                         \
                        (head)->next = (queue_entry_t)(elt);            \
                } else {                        /* last element */      \
                        __prev = (elt)->field.prev = (head)->prev;      \
-                       ((type)__prev)->field.next = (queue_entry_t)(elt);\
+                       ((type)(void *)__prev)->field.next =            \
+                               (queue_entry_t)(elt);                   \
                }                                                       \
                (head)->prev = (queue_entry_t)(elt);                    \
        } else {                                                        \
@@ -418,7 +815,8 @@ MACRO_BEGIN                                                         \
                        (head)->next = (queue_entry_t)(elt);            \
                } else {                        /* middle element */    \
                        __prev = (elt)->field.prev = (cur)->field.prev; \
-                       ((type)__prev)->field.next = (queue_entry_t)(elt);\
+                       ((type)(void *)__prev)->field.next =            \
+                               (queue_entry_t)(elt);                   \
                }                                                       \
                (cur)->field.prev = (queue_entry_t)(elt);               \
        }                                                               \
@@ -435,10 +833,12 @@ MACRO_END
  *                     <type> cur;
  *                     <type> is what's in our queue
  *                     <field> is the chain field in (*<type>)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define queue_insert_after(head, elt, cur, type, field)                        \
 MACRO_BEGIN                                                            \
-       register queue_entry_t __next;                                  \
+       queue_entry_t __next;                                           \
                                                                        \
        if ((head) == (queue_entry_t)(cur)) {                           \
                (elt)->field.prev = (head);                             \
@@ -447,7 +847,8 @@ MACRO_BEGIN                                                         \
                        (head)->prev = (queue_entry_t)(elt);            \
                } else {                        /* first element */     \
                        __next = (elt)->field.next = (head)->next;      \
-                       ((type)__next)->field.prev = (queue_entry_t)(elt);\
+                       ((type)(void *)__next)->field.prev =            \
+                               (queue_entry_t)(elt);                   \
                }                                                       \
                (head)->next = (queue_entry_t)(elt);                    \
        } else {                                                        \
@@ -458,7 +859,8 @@ MACRO_BEGIN                                                         \
                        (head)->prev = (queue_entry_t)(elt);            \
                } else {                        /* middle element */    \
                        __next = (elt)->field.next = (cur)->field.next; \
-                       ((type)__next)->field.prev = (queue_entry_t)(elt);\
+                       ((type)(void *)__next)->field.prev =            \
+                               (queue_entry_t)(elt);                   \
                }                                                       \
                (cur)->field.next = (queue_entry_t)(elt);               \
        }                                                               \
@@ -469,9 +871,11 @@ MACRO_END
  *     Function:
  *             Find the queue_chain_t (or queue_t) for the
  *             given element (thing) in the given queue (head)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define        queue_field(head, thing, type, field)                   \
-               (((head) == (thing)) ? (head) : &((type)(thing))->field)
+               (((head) == (thing)) ? (head) : &((type)(void *)(thing))->field)
 
 /*
  *     Macro:          queue_remove
@@ -480,10 +884,12 @@ MACRO_END
  *     Header:
  *             void queue_remove(q, qe, type, field)
  *                     arguments as in queue_enter
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define        queue_remove(head, elt, type, field)                    \
 MACRO_BEGIN                                                    \
-       register queue_entry_t  __next, __prev;                 \
+       queue_entry_t   __next, __prev;                         \
                                                                \
        __next = (elt)->field.next;                             \
        __prev = (elt)->field.prev;                             \
@@ -491,12 +897,12 @@ MACRO_BEGIN                                                       \
        if ((head) == __next)                                   \
                (head)->prev = __prev;                          \
        else                                                    \
-               ((type)__next)->field.prev = __prev;            \
+               ((type)(void *)__next)->field.prev = __prev;    \
                                                                \
        if ((head) == __prev)                                   \
                (head)->next = __next;                          \
        else                                                    \
-               ((type)__prev)->field.next = __next;            \
+               ((type)(void *)__prev)->field.next = __next;    \
                                                                \
        (elt)->field.next = NULL;                               \
        (elt)->field.prev = NULL;                               \
@@ -510,18 +916,20 @@ MACRO_END
  *     Header:
  *             queue_remove_first(head, entry, type, field)
  *             entry is returned by reference
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define        queue_remove_first(head, entry, type, field)            \
 MACRO_BEGIN                                                    \
-       register queue_entry_t  __next;                         \
+       queue_entry_t   __next;                                 \
                                                                \
-       (entry) = (type) ((head)->next);                        \
+       (entry) = (type)(void *) ((head)->next);                \
        __next = (entry)->field.next;                           \
                                                                \
        if ((head) == __next)                                   \
                (head)->prev = (head);                          \
        else                                                    \
-               ((type)(__next))->field.prev = (head);          \
+               ((type)(void *)(__next))->field.prev = (head);  \
        (head)->next = __next;                                  \
                                                                \
        (entry)->field.next = NULL;                             \
@@ -536,18 +944,20 @@ MACRO_END
  *     Header:
  *             queue_remove_last(head, entry, type, field)
  *             entry is returned by reference
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define        queue_remove_last(head, entry, type, field)             \
 MACRO_BEGIN                                                    \
-       register queue_entry_t  __prev;                         \
+       queue_entry_t   __prev;                                 \
                                                                \
-       (entry) = (type) ((head)->prev);                        \
+       (entry) = (type)(void *) ((head)->prev);                \
        __prev = (entry)->field.prev;                           \
                                                                \
        if ((head) == __prev)                                   \
                (head)->next = (head);                          \
        else                                                    \
-               ((type)(__prev))->field.next = (head);          \
+               ((type)(void *)(__prev))->field.next = (head);  \
        (head)->prev = __prev;                                  \
                                                                \
        (entry)->field.next = NULL;                             \
@@ -556,11 +966,13 @@ MACRO_END
 
 /*
  *     Macro:          queue_assign
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define        queue_assign(to, from, type, field)                     \
 MACRO_BEGIN                                                    \
-       ((type)((from)->prev))->field.next = (to);              \
-       ((type)((from)->next))->field.prev = (to);              \
+       ((type)(void *)((from)->prev))->field.next = (to);      \
+       ((type)(void *)((from)->next))->field.prev = (to);      \
        *to = *from;                                            \
 MACRO_END
 
@@ -574,13 +986,17 @@ MACRO_END
  *                     queue_t new;
  *                     <type> is what's in our queue
  *                      <field> is the chain field in (*<type>)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define queue_new_head(old, new, type, field)                  \
 MACRO_BEGIN                                                    \
        if (!queue_empty(old)) {                                \
                *(new) = *(old);                                \
-               ((type)((new)->next))->field.prev = (new);      \
-               ((type)((new)->prev))->field.next = (new);      \
+               ((type)(void *)((new)->next))->field.prev =     \
+                       (new);                                  \
+               ((type)(void *)((new)->prev))->field.next =     \
+                       (new);                                  \
        } else {                                                \
                queue_init(new);                                \
        }                                                       \
@@ -598,15 +1014,17 @@ MACRO_END
  *                     <type> elt;
  *                     <type> is what's in our queue
  *                     <field> is the chain field in (*<type>)
+ *     Note:
+ *             This should only be used with Method 2 queue iteration (element chains)
  */
 #define queue_iterate(head, elt, type, field)                  \
-       for ((elt) = (type) queue_first(head);                  \
+       for ((elt) = (type)(void *) queue_first(head);          \
             !queue_end((head), (queue_entry_t)(elt));          \
-            (elt) = (type) queue_next(&(elt)->field))
+            (elt) = (type)(void *) queue_next(&(elt)->field))
 
 #ifdef MACH_KERNEL_PRIVATE
 
-#include <kern/lock.h>
+#include <kern/locks.h>
 
 /*----------------------------------------------------------------*/
 /*
@@ -614,8 +1032,12 @@ MACRO_END
  */
 struct mpqueue_head {
        struct queue_entry      head;           /* header for queue */
+       uint64_t                earliest_soft_deadline;
+       uint64_t                count;
        lck_mtx_t               lock_data;
+#if defined(__i386__) || defined(__x86_64__)
        lck_mtx_ext_t           lock_data_ext;
+#endif
 };
 
 typedef struct mpqueue_head    mpqueue_head_t;
@@ -632,6 +1054,8 @@ MACRO_BEGIN                                                \
                         &(q)->lock_data_ext,           \
                         lck_grp,                       \
                         lck_attr);                     \
+       (q)->earliest_soft_deadline = UINT64_MAX;       \
+       (q)->count = 0;                                 \
 MACRO_END
 
 #else
@@ -639,7 +1063,7 @@ MACRO_END
 #define mpqueue_init(q, lck_grp, lck_attr)             \
 MACRO_BEGIN                                            \
        queue_init(&(q)->head);                         \
-        lck_spin_init(&(q)->lock_data,                 \
+        lck_mtx_init(&(q)->lock_data,                  \
                      lck_grp,                          \
                      lck_attr);                        \
 MACRO_END
@@ -665,4 +1089,6 @@ MACRO_END
 
 #endif /* MACH_KERNEL_PRIVATE */
 
+__END_DECLS
+
 #endif /* _KERN_QUEUE_H_ */