__BEGIN_DECLS
/*
- * Queue of abstract objects. Queue is maintained
- * within that object.
+ * Queue Management APIs
*
- * Supports fast removal from within the queue.
+ * 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)
*
- * 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.
+ * Both methods use a common queue head and linkage pattern:
+ * The head of a queue is declared as:
+ * queue_head_t q_head;
*
- * Declare the queue as a "queue_t" type.
+ * 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)
*
- * 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.
+ * 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.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * ++ 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
+ *
+ * [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;
__DEQUEUE_ELT_CLEANUP(elt);
}
+/*
+ * 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
* Function:
(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:
*/
#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);
+}
/*----------------------------------------------------------------*/
/*
* <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 \
* <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 \
* <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 \
* <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 \
* 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)(void *)(thing))->field)
* 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 \
* 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 \
* 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 \
/*
* 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 \
* 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 \
* <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)(void *) queue_first(head); \
struct queue_entry head; /* header for queue */
uint64_t earliest_soft_deadline;
uint64_t count;
-#if defined(__i386__) || defined(__x86_64__)
lck_mtx_t lock_data;
+#if defined(__i386__) || defined(__x86_64__)
lck_mtx_ext_t lock_data_ext;
-#else
- lck_spin_t lock_data;
#endif
};
#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
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