* Copyright (c) 2000-2009 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- *
+ *
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
- *
+ *
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
- *
+ *
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
- *
+ *
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
*/
-/*
+/*
* Mach Operating System
* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
* All Rights Reserved.
- *
+ *
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
- *
+ *
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- *
+ *
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
*
*/
-#ifndef _KERN_QUEUE_H_
-#define _KERN_QUEUE_H_
+#ifndef _KERN_QUEUE_H_
+#define _KERN_QUEUE_H_
#include <mach/mach_types.h>
#include <kern/macro_help.h>
+#include <sys/cdefs.h>
+#include <string.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.
+ *
+ * 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
*
- * Supports fast removal from within the queue.
+ * [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
*
- * 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.
+ * 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.
*
- * Declare the queue as a "queue_t" type.
+ * 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.
*
- * 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.
+ * ++ 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 */
+ 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;
-typedef struct queue_entry queue_chain_t;
-typedef struct queue_entry *queue_entry_t;
+typedef struct queue_entry *queue_t;
+typedef struct queue_entry queue_head_t;
+typedef struct queue_entry queue_chain_t;
+typedef struct queue_entry *queue_entry_t;
/*
* enqueue puts "elt" on the "queue".
* remqueue removes the specified "elt" from its queue.
*/
-#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);
+#define enqueue(queue, elt) enqueue_tail(queue, elt)
+#define dequeue(queue) dequeue_head(queue)
-/* 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);
+#ifdef XNU_KERNEL_PRIVATE
+#include <kern/debug.h>
+static inline void
+__QUEUE_ELT_VALIDATE(queue_entry_t elt)
+{
+ queue_entry_t elt_next, elt_prev;
-/* Dequeue element */
-extern void remque(
- queue_entry_t elt);
+ if (__improbable(elt == (queue_entry_t)NULL)) {
+ panic("Invalid queue element %p", elt);
+ }
-__END_DECLS
+ elt_next = elt->next;
+ elt_prev = elt->prev;
-#else /* !__GNUC__ */
+ if (__improbable(elt_next == (queue_entry_t)NULL || elt_prev == (queue_entry_t)NULL)) {
+ 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);
+ }
+}
-#ifdef XNU_KERNEL_PRIVATE
-#define __DEQUEUE_ELT_CLEANUP(elt) do { \
- (elt)->next = (queue_entry_t) 0; \
- (elt)->prev = (queue_entry_t) 0; \
- } while (0)
+static inline void
+__DEQUEUE_ELT_CLEANUP(queue_entry_t elt)
+{
+ (elt)->next = (queue_entry_t)NULL;
+ (elt)->prev = (queue_entry_t)NULL;
+}
#else
+#define __QUEUE_ELT_VALIDATE(elt) do { } while (0)
#define __DEQUEUE_ELT_CLEANUP(elt) do { } while(0)
#endif /* !XNU_KERNEL_PRIVATE */
static __inline__ void
enqueue_head(
- queue_t que,
- queue_entry_t elt)
+ 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;
}
static __inline__ void
enqueue_tail(
- queue_t que,
- queue_entry_t elt)
+ 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;
}
static __inline__ queue_entry_t
dequeue_head(
- queue_t que)
+ queue_t que)
{
- register queue_entry_t elt = (queue_entry_t) 0;
+ queue_entry_t elt = (queue_entry_t)NULL;
+ 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);
}
- return (elt);
+ return elt;
}
static __inline__ queue_entry_t
dequeue_tail(
- queue_t que)
+ queue_t que)
{
- register queue_entry_t elt = (queue_entry_t) 0;
+ queue_entry_t elt = (queue_entry_t)NULL;
+ 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);
}
- return (elt);
+ return elt;
}
static __inline__ void
remqueue(
- 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);
}
static __inline__ void
insque(
- queue_entry_t entry,
- queue_entry_t pred)
+ 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;
- __DEQUEUE_ELT_CLEANUP(elt);
+ remqueue(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) __container_of(qe, 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; \
+})
+
+/* 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
* void queue_init(q)
* queue_t q; \* MODIFIED *\
*/
-#define queue_init(q) \
-MACRO_BEGIN \
+#define queue_init(q) \
+MACRO_BEGIN \
(q)->next = (q);\
(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:
* queue_entry_t queue_first(q)
* queue_t q; \* IN *\
*/
-#define queue_first(q) ((q)->next)
+#define queue_first(q) ((q)->next)
/*
* Macro: queue_next
* queue_entry_t queue_next(qc)
* queue_t qc;
*/
-#define queue_next(qc) ((qc)->next)
+#define queue_next(qc) ((qc)->next)
/*
* Macro: queue_last
* queue_entry_t queue_last(q)
* queue_t q; \* IN *\
*/
-#define queue_last(q) ((q)->prev)
+#define queue_last(q) ((q)->prev)
/*
* Macro: queue_prev
* queue_entry_t queue_prev(qc)
* queue_t qc;
*/
-#define queue_prev(qc) ((qc)->prev)
+#define queue_prev(qc) ((qc)->prev)
/*
* Macro: queue_end
* queue_t q;
* queue_entry_t qe;
*/
-#define queue_end(q, qe) ((q) == (qe))
+#define queue_end(q, qe) ((q) == (qe))
/*
* Macro: queue_empty
* boolean_t queue_empty(q)
* queue_t q;
*/
-#define queue_empty(q) queue_end((q), queue_first(q))
+#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)
+ *
+ * We insert a compiler barrier after setting the fields in the element
+ * to ensure that the element is updated before being added to the queue,
+ * which is especially important because stackshot, which operates from
+ * debugger context, iterates several queues that use this macro (the tasks
+ * lists and threads lists) without locks. Without this barrier, the
+ * compiler may re-order the instructions for this macro in a way that
+ * could cause stackshot to trip over an inconsistent queue during
+ * iteration.
*/
-#define queue_enter(head, elt, type, field) \
-MACRO_BEGIN \
- register queue_entry_t __prev; \
- \
- __prev = (head)->prev; \
- if ((head) == __prev) { \
- (head)->next = (queue_entry_t) (elt); \
- } \
- else { \
- ((type)(void *)__prev)->field.next = \
- (queue_entry_t)(elt); \
- } \
- (elt)->field.prev = __prev; \
- (elt)->field.next = head; \
- (head)->prev = (queue_entry_t) elt; \
+#define queue_enter(head, elt, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __prev; \
+ \
+ __prev = (head)->prev; \
+ (elt)->field.prev = __prev; \
+ (elt)->field.next = head; \
+ __compiler_barrier(); \
+ if ((head) == __prev) { \
+ (head)->next = (queue_entry_t) (elt); \
+ } \
+ else { \
+ ((type)(void *)__prev)->field.next = \
+ (queue_entry_t)(elt); \
+ } \
+ (head)->prev = (queue_entry_t) elt; \
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; \
- \
- __next = (head)->next; \
- if ((head) == __next) { \
- (head)->prev = (queue_entry_t) (elt); \
- } \
- else { \
- ((type)(void *)__next)->field.prev = \
- (queue_entry_t)(elt); \
- } \
- (elt)->field.next = __next; \
- (elt)->field.prev = head; \
- (head)->next = (queue_entry_t) elt; \
+#define queue_enter_first(head, elt, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __next; \
+ \
+ __next = (head)->next; \
+ if ((head) == __next) { \
+ (head)->prev = (queue_entry_t) (elt); \
+ } \
+ else { \
+ ((type)(void *)__next)->field.prev = \
+ (queue_entry_t)(elt); \
+ } \
+ (elt)->field.next = __next; \
+ (elt)->field.prev = head; \
+ (head)->next = (queue_entry_t) elt; \
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; \
- \
- if ((head) == (queue_entry_t)(cur)) { \
- (elt)->field.next = (head); \
- if ((head)->next == (head)) { /* only element */ \
- (elt)->field.prev = (head); \
- (head)->next = (queue_entry_t)(elt); \
- } else { /* last element */ \
- __prev = (elt)->field.prev = (head)->prev; \
- ((type)(void *)__prev)->field.next = \
- (queue_entry_t)(elt); \
- } \
- (head)->prev = (queue_entry_t)(elt); \
- } else { \
- (elt)->field.next = (queue_entry_t)(cur); \
- if ((head)->next == (queue_entry_t)(cur)) { \
- /* first element */ \
- (elt)->field.prev = (head); \
- (head)->next = (queue_entry_t)(elt); \
- } else { /* middle element */ \
- __prev = (elt)->field.prev = (cur)->field.prev; \
- ((type)(void *)__prev)->field.next = \
- (queue_entry_t)(elt); \
- } \
- (cur)->field.prev = (queue_entry_t)(elt); \
- } \
+#define queue_insert_before(head, elt, cur, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __prev; \
+ \
+ if ((head) == (queue_entry_t)(cur)) { \
+ (elt)->field.next = (head); \
+ if ((head)->next == (head)) { /* only element */ \
+ (elt)->field.prev = (head); \
+ (head)->next = (queue_entry_t)(elt); \
+ } else { /* last element */ \
+ __prev = (elt)->field.prev = (head)->prev; \
+ ((type)(void *)__prev)->field.next = \
+ (queue_entry_t)(elt); \
+ } \
+ (head)->prev = (queue_entry_t)(elt); \
+ } else { \
+ (elt)->field.next = (queue_entry_t)(cur); \
+ if ((head)->next == (queue_entry_t)(cur)) { \
+ /* first element */ \
+ (elt)->field.prev = (head); \
+ (head)->next = (queue_entry_t)(elt); \
+ } else { /* middle element */ \
+ __prev = (elt)->field.prev = (cur)->field.prev; \
+ ((type)(void *)__prev)->field.next = \
+ (queue_entry_t)(elt); \
+ } \
+ (cur)->field.prev = (queue_entry_t)(elt); \
+ } \
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; \
- \
- if ((head) == (queue_entry_t)(cur)) { \
- (elt)->field.prev = (head); \
- if ((head)->next == (head)) { /* only element */ \
- (elt)->field.next = (head); \
- (head)->prev = (queue_entry_t)(elt); \
- } else { /* first element */ \
- __next = (elt)->field.next = (head)->next; \
- ((type)(void *)__next)->field.prev = \
- (queue_entry_t)(elt); \
- } \
- (head)->next = (queue_entry_t)(elt); \
- } else { \
- (elt)->field.prev = (queue_entry_t)(cur); \
- if ((head)->prev == (queue_entry_t)(cur)) { \
- /* last element */ \
- (elt)->field.next = (head); \
- (head)->prev = (queue_entry_t)(elt); \
- } else { /* middle element */ \
- __next = (elt)->field.next = (cur)->field.next; \
- ((type)(void *)__next)->field.prev = \
- (queue_entry_t)(elt); \
- } \
- (cur)->field.next = (queue_entry_t)(elt); \
- } \
+#define queue_insert_after(head, elt, cur, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __next; \
+ \
+ if ((head) == (queue_entry_t)(cur)) { \
+ (elt)->field.prev = (head); \
+ if ((head)->next == (head)) { /* only element */ \
+ (elt)->field.next = (head); \
+ (head)->prev = (queue_entry_t)(elt); \
+ } else { /* first element */ \
+ __next = (elt)->field.next = (head)->next; \
+ ((type)(void *)__next)->field.prev = \
+ (queue_entry_t)(elt); \
+ } \
+ (head)->next = (queue_entry_t)(elt); \
+ } else { \
+ (elt)->field.prev = (queue_entry_t)(cur); \
+ if ((head)->prev == (queue_entry_t)(cur)) { \
+ /* last element */ \
+ (elt)->field.next = (head); \
+ (head)->prev = (queue_entry_t)(elt); \
+ } else { /* middle element */ \
+ __next = (elt)->field.next = (cur)->field.next; \
+ ((type)(void *)__next)->field.prev = \
+ (queue_entry_t)(elt); \
+ } \
+ (cur)->field.next = (queue_entry_t)(elt); \
+ } \
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)(void *)(thing))->field)
+#define queue_field(head, thing, type, field) \
+ (((head) == (thing)) ? (head) : &((type)(void *)(thing))->field)
/*
* Macro: queue_remove
* 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; \
- \
- __next = (elt)->field.next; \
- __prev = (elt)->field.prev; \
- \
- if ((head) == __next) \
- (head)->prev = __prev; \
- else \
- ((type)(void *)__next)->field.prev = __prev; \
- \
- if ((head) == __prev) \
- (head)->next = __next; \
- else \
- ((type)(void *)__prev)->field.next = __next; \
- \
- (elt)->field.next = NULL; \
- (elt)->field.prev = NULL; \
+#define queue_remove(head, elt, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __next, __prev; \
+ \
+ __next = (elt)->field.next; \
+ __prev = (elt)->field.prev; \
+ \
+ if ((head) == __next) \
+ (head)->prev = __prev; \
+ else \
+ ((type)(void *)__next)->field.prev = __prev; \
+ \
+ if ((head) == __prev) \
+ (head)->next = __next; \
+ else \
+ ((type)(void *)__prev)->field.next = __next; \
+ \
+ (elt)->field.next = NULL; \
+ (elt)->field.prev = NULL; \
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; \
- \
- (entry) = (type)(void *) ((head)->next); \
- __next = (entry)->field.next; \
- \
- if ((head) == __next) \
- (head)->prev = (head); \
- else \
- ((type)(void *)(__next))->field.prev = (head); \
- (head)->next = __next; \
- \
- (entry)->field.next = NULL; \
- (entry)->field.prev = NULL; \
+#define queue_remove_first(head, entry, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __next; \
+ \
+ (entry) = (type)(void *) ((head)->next); \
+ __next = (entry)->field.next; \
+ \
+ if ((head) == __next) \
+ (head)->prev = (head); \
+ else \
+ ((type)(void *)(__next))->field.prev = (head); \
+ (head)->next = __next; \
+ \
+ (entry)->field.next = NULL; \
+ (entry)->field.prev = NULL; \
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; \
- \
- (entry) = (type)(void *) ((head)->prev); \
- __prev = (entry)->field.prev; \
- \
- if ((head) == __prev) \
- (head)->next = (head); \
- else \
- ((type)(void *)(__prev))->field.next = (head); \
- (head)->prev = __prev; \
- \
- (entry)->field.next = NULL; \
- (entry)->field.prev = NULL; \
+#define queue_remove_last(head, entry, type, field) \
+MACRO_BEGIN \
+ queue_entry_t __prev; \
+ \
+ (entry) = (type)(void *) ((head)->prev); \
+ __prev = (entry)->field.prev; \
+ \
+ if ((head) == __prev) \
+ (head)->next = (head); \
+ else \
+ ((type)(void *)(__prev))->field.next = (head); \
+ (head)->prev = __prev; \
+ \
+ (entry)->field.next = NULL; \
+ (entry)->field.prev = NULL; \
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)(void *)((from)->prev))->field.next = (to); \
- ((type)(void *)((from)->next))->field.prev = (to); \
- *to = *from; \
+#define queue_assign(to, from, type, field) \
+MACRO_BEGIN \
+ ((type)(void *)((from)->prev))->field.next = (to); \
+ ((type)(void *)((from)->next))->field.prev = (to); \
+ *to = *from; \
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)(void *)((new)->next))->field.prev = \
- (new); \
- ((type)(void *)((new)->prev))->field.next = \
- (new); \
- } else { \
- queue_init(new); \
- } \
+#define queue_new_head(old, new, type, field) \
+MACRO_BEGIN \
+ if (!queue_empty(old)) { \
+ *(new) = *(old); \
+ ((type)(void *)((new)->next))->field.prev = \
+ (new); \
+ ((type)(void *)((new)->prev))->field.next = \
+ (new); \
+ } else { \
+ queue_init(new); \
+ } \
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)(void *) queue_first(head); \
- !queue_end((head), (queue_entry_t)(elt)); \
+#define queue_iterate(head, elt, type, field) \
+ for ((elt) = (type)(void *) queue_first(head); \
+ !queue_end((head), (queue_entry_t)(elt)); \
(elt) = (type)(void *) queue_next(&(elt)->field))
-#ifdef MACH_KERNEL_PRIVATE
-
-#include <kern/lock.h>
-/*----------------------------------------------------------------*/
-/*
- * Define macros for queues with locks.
- */
-struct mpqueue_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;
- lck_mtx_ext_t lock_data_ext;
-#else
- lck_spin_t lock_data;
-#endif
-};
-
-typedef struct mpqueue_head mpqueue_head_t;
-
-#define round_mpq(size) (size)
-
-
-#if defined(__i386__) || defined(__x86_64__)
-
-#define mpqueue_init(q, lck_grp, lck_attr) \
-MACRO_BEGIN \
- queue_init(&(q)->head); \
- lck_mtx_init_ext(&(q)->lock_data, \
- &(q)->lock_data_ext, \
- lck_grp, \
- lck_attr); \
- (q)->earliest_soft_deadline = UINT64_MAX; \
- (q)->count = 0; \
-MACRO_END
-
-#else
-
-#define mpqueue_init(q, lck_grp, lck_attr) \
-MACRO_BEGIN \
- queue_init(&(q)->head); \
- lck_spin_init(&(q)->lock_data, \
- lck_grp, \
- lck_attr); \
-MACRO_END
-#endif
-
-
-#define mpenqueue_tail(q, elt) \
-MACRO_BEGIN \
- lck_mtx_lock_spin_always(&(q)->lock_data); \
- enqueue_tail(&(q)->head, elt); \
- lck_mtx_unlock_always(&(q)->lock_data); \
-MACRO_END
-
-#define mpdequeue_head(q, elt) \
-MACRO_BEGIN \
- lck_mtx_lock_spin_always(&(q)->lock_data); \
- if (queue_empty(&(q)->head)) \
- *(elt) = 0; \
- else \
- *(elt) = dequeue_head(&(q)->head); \
- lck_mtx_unlock_always(&(q)->lock_data); \
-MACRO_END
-
-#endif /* MACH_KERNEL_PRIVATE */
+__END_DECLS
-#endif /* _KERN_QUEUE_H_ */
+#endif /* _KERN_QUEUE_H_ */
projects / apple / xnu.git / blobdiff