[PATCH] rbtree: support functions used by the io schedulers

They all duplicate macros to check for empty root and/or node, and
clearing a node. So put those in rbtree.h.
Signed-off-by: Jens Axboe <axboe@suse.de>

block/as-iosched.c

@@ -347,9 +347,6 @@ static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
 /*
  * rb tree support functions
  */
-#define RB_EMPTY(root)	((root)->rb_node == NULL)
-#define ON_RB(node)	(rb_parent(node) != node)
-#define RB_CLEAR(node)	(rb_set_parent(node, node))
 #define rb_entry_arq(node)	rb_entry((node), struct as_rq, rb_node)
 #define ARQ_RB_ROOT(ad, arq)	(&(ad)->sort_list[(arq)->is_sync])
 #define rq_rb_key(rq)		(rq)->sector
@@ -418,13 +415,13 @@ static void as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
 
 static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
 {
-	if (!ON_RB(&arq->rb_node)) {
+	if (!RB_EMPTY_NODE(&arq->rb_node)) {
 		WARN_ON(1);
 		return;
 	}
 
 	rb_erase(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
-	RB_CLEAR(&arq->rb_node);
+	RB_CLEAR_NODE(&arq->rb_node);
 }
 
 static struct request *
@@ -545,7 +542,7 @@ static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *last)
 	struct rb_node *rbprev = rb_prev(&last->rb_node);
 	struct as_rq *arq_next, *arq_prev;
 
-	BUG_ON(!ON_RB(&last->rb_node));
+	BUG_ON(!RB_EMPTY_NODE(&last->rb_node));
 
 	if (rbprev)
 		arq_prev = rb_entry_arq(rbprev);
@@ -1122,7 +1119,7 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
 	struct request *rq = arq->request;
 	const int data_dir = arq->is_sync;
 
-	BUG_ON(!ON_RB(&arq->rb_node));
+	BUG_ON(!RB_EMPTY_NODE(&arq->rb_node));
 
 	as_antic_stop(ad);
 	ad->antic_status = ANTIC_OFF;
@@ -1247,7 +1244,7 @@ static int as_dispatch_request(request_queue_t *q, int force)
 	 */
 
 	if (reads) {
-		BUG_ON(RB_EMPTY(&ad->sort_list[REQ_SYNC]));
+		BUG_ON(RB_EMPTY_ROOT(&ad->sort_list[REQ_SYNC]));
 
 		if (writes && ad->batch_data_dir == REQ_SYNC)
 			/*
@@ -1271,7 +1268,7 @@ static int as_dispatch_request(request_queue_t *q, int force)
 
 	if (writes) {
 dispatch_writes:
-		BUG_ON(RB_EMPTY(&ad->sort_list[REQ_ASYNC]));
+		BUG_ON(RB_EMPTY_ROOT(&ad->sort_list[REQ_ASYNC]));
 
 		if (ad->batch_data_dir == REQ_SYNC) {
 			ad->changed_batch = 1;
@@ -1591,7 +1588,7 @@ static int as_set_request(request_queue_t *q, struct request *rq,
 
 	if (arq) {
 		memset(arq, 0, sizeof(*arq));
-		RB_CLEAR(&arq->rb_node);
+		RB_CLEAR_NODE(&arq->rb_node);
 		arq->request = rq;
 		arq->state = AS_RQ_PRESCHED;
 		arq->io_context = NULL;

block/cfq-iosched.c

@@ -60,11 +60,6 @@ static DEFINE_SPINLOCK(cfq_exit_lock);
 /*
  * rb-tree defines
  */
-#define RB_EMPTY(node)		((node)->rb_node == NULL)
-#define RB_CLEAR(node)		do {	\
-		memset(node, 0, sizeof(*node)); \
-} while (0)
-#define RB_CLEAR_ROOT(root)	((root)->rb_node = NULL)
 #define rb_entry_crq(node)	rb_entry((node), struct cfq_rq, rb_node)
 #define rq_rb_key(rq)		(rq)->sector
 
@@ -559,7 +554,7 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq)
 
 	rb_erase(&crq->rb_node, &cfqq->sort_list);
 
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
+	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
 		cfq_del_cfqq_rr(cfqd, cfqq);
 }
 
@@ -914,7 +909,7 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	struct cfq_io_context *cic;
 	unsigned long sl;
 
-	WARN_ON(!RB_EMPTY(&cfqq->sort_list));
+	WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
 	WARN_ON(cfqq != cfqd->active_queue);
 
 	/*
@@ -1042,7 +1037,7 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
 	 * if queue has requests, dispatch one. if not, check if
 	 * enough slice is left to wait for one
 	 */
-	if (!RB_EMPTY(&cfqq->sort_list))
+	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
 		goto keep_queue;
 	else if (cfq_cfqq_dispatched(cfqq)) {
 		cfqq = NULL;
@@ -1066,7 +1061,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 {
 	int dispatched = 0;
 
-	BUG_ON(RB_EMPTY(&cfqq->sort_list));
+	BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
 
 	do {
 		struct cfq_rq *crq;
@@ -1090,7 +1085,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 			cfqd->active_cic = crq->io_context;
 		}
 
-		if (RB_EMPTY(&cfqq->sort_list))
+		if (RB_EMPTY_ROOT(&cfqq->sort_list))
 			break;
 
 	} while (dispatched < max_dispatch);
@@ -1480,7 +1475,6 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
 
 		INIT_HLIST_NODE(&cfqq->cfq_hash);
 		INIT_LIST_HEAD(&cfqq->cfq_list);
-		RB_CLEAR_ROOT(&cfqq->sort_list);
 		INIT_LIST_HEAD(&cfqq->fifo);
 
 		cfqq->key = key;
@@ -1873,7 +1867,7 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
 	if (cfqd->active_queue == cfqq) {
 		if (time_after(now, cfqq->slice_end))
 			cfq_slice_expired(cfqd, 0);
-		else if (sync && RB_EMPTY(&cfqq->sort_list)) {
+		else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
 			if (!cfq_arm_slice_timer(cfqd, cfqq))
 				cfq_schedule_dispatch(cfqd);
 		}
@@ -2059,7 +2053,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
 
 	crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
 	if (crq) {
-		RB_CLEAR(&crq->rb_node);
+		RB_CLEAR_NODE(&crq->rb_node);
 		crq->rb_key = 0;
 		crq->request = rq;
 		INIT_HLIST_NODE(&crq->hash);
@@ -2151,7 +2145,7 @@ static void cfq_idle_slice_timer(unsigned long data)
 		/*
 		 * not expired and it has a request pending, let it dispatch
 		 */
-		if (!RB_EMPTY(&cfqq->sort_list)) {
+		if (!RB_EMPTY_ROOT(&cfqq->sort_list)) {
 			cfq_mark_cfqq_must_dispatch(cfqq);
 			goto out_kick;
 		}

block/deadline-iosched.c

@@ -159,9 +159,6 @@ deadline_find_drq_hash(struct deadline_data *dd, sector_t offset)
 /*
  * rb tree support functions
  */
-#define RB_EMPTY(root)	((root)->rb_node == NULL)
-#define ON_RB(node)	(rb_parent(node) != node)
-#define RB_CLEAR(node)	(rb_set_parent(node, node))
 #define rb_entry_drq(node)	rb_entry((node), struct deadline_rq, rb_node)
 #define DRQ_RB_ROOT(dd, drq)	(&(dd)->sort_list[rq_data_dir((drq)->request)])
 #define rq_rb_key(rq)		(rq)->sector
@@ -220,9 +217,9 @@ deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
 			dd->next_drq[data_dir] = rb_entry_drq(rbnext);
 	}
 
-	BUG_ON(!ON_RB(&drq->rb_node));
+	BUG_ON(!RB_EMPTY_NODE(&drq->rb_node));
 	rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
-	RB_CLEAR(&drq->rb_node);
+	RB_CLEAR_NODE(&drq->rb_node);
 }
 
 static struct request *
@@ -496,7 +493,7 @@ static int deadline_dispatch_requests(request_queue_t *q, int force)
 	 */
 
 	if (reads) {
-		BUG_ON(RB_EMPTY(&dd->sort_list[READ]));
+		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));
 
 		if (writes && (dd->starved++ >= dd->writes_starved))
 			goto dispatch_writes;
@@ -512,7 +509,7 @@ static int deadline_dispatch_requests(request_queue_t *q, int force)
 
 	if (writes) {
 dispatch_writes:
-		BUG_ON(RB_EMPTY(&dd->sort_list[WRITE]));
+		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE]));
 
 		dd->starved = 0;
 
@@ -668,7 +665,7 @@ deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
 	drq = mempool_alloc(dd->drq_pool, gfp_mask);
 	if (drq) {
 		memset(drq, 0, sizeof(*drq));
-		RB_CLEAR(&drq->rb_node);
+		RB_CLEAR_NODE(&drq->rb_node);
 		drq->request = rq;
 
 		INIT_HLIST_NODE(&drq->hash);

include/linux/rbtree.h

@@ -132,6 +132,10 @@ static inline void rb_set_color(struct rb_node *rb, int color)
 #define RB_ROOT	(struct rb_root) { NULL, }
 #define	rb_entry(ptr, type, member) container_of(ptr, type, member)
 
+#define RB_EMPTY_ROOT(root)	((root)->rb_node == NULL)
+#define RB_EMPTY_NODE(node)	(rb_parent(node) != node)
+#define RB_CLEAR_NODE(node)	(rb_set_parent(node, node))
+
 extern void rb_insert_color(struct rb_node *, struct rb_root *);
 extern void rb_erase(struct rb_node *, struct rb_root *);