[RFC][patch 7/11][CFQ-cgroup] Control cfq_data per driver

["Satoshi UCHIDA" <s-uchida@ap.jp.nec.com>]

This patch expands cfq_meta_data to handling multi cfq_data.
This control is used rb_tree and the key is used a pointer of cfq_data.

   Signed-off-by: Satoshi UCHIDA <uchida@ap.jp.nec.com>

diff --git a/block/cfq-cgroup.c b/block/cfq-cgroup.c
index 34894d9..55090dc 100644
--- a/block/cfq-cgroup.c
+++ b/block/cfq-cgroup.c
@@ -54,9 +54,42 @@ static struct cfq_meta_data *cfq_cgroup_init_meta_data(struct cfq_data *cfqd, st
 	cfqmd->cfq_driv_d.idle_slice_timer.data = (unsigned long) cfqd;
 	cfqmd->cfq_driv_d.cfq_slice_idle = cfq_cgroup_slice_idle;
 
+	cfqmd->sibling_tree = RB_ROOT;
+	cfqmd->siblings = 0;
+
 	return cfqmd;
 }
 
+static void cfq_meta_data_sibling_tree_add(struct cfq_meta_data *cfqmd,
+					     struct cfq_data *cfqd)
+{
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+
+	BUG_ON(!RB_EMPTY_NODE(&cfqd->sib_node));
+
+	p = &cfqmd->sibling_tree.rb_node;
+
+	while (*p) {
+		struct cfq_data *__cfqd;
+		struct rb_node **n;
+
+		parent = *p;
+		__cfqd = rb_entry(parent, struct cfq_data, sib_node);
+
+		if (cfqd < __cfqd) {
+			n = &(*p)->rb_left;
+		} else {
+			n = &(*p)->rb_right;
+		}
+		p = n;
+	}
+		
+	rb_link_node(&cfqd->sib_node, parent, p);
+	rb_insert_color(&cfqd->sib_node, &cfqmd->sibling_tree);
+	cfqmd->siblings++;
+	cfqd->cfqmd = cfqmd;
+}
  
 struct cfq_data *__cfq_cgroup_init_queue(struct request_queue *q, void *data)
 {
@@ -66,6 +99,8 @@ struct cfq_data *__cfq_cgroup_init_queue(struct request_queue *q, void *data)
 	if (!cfqd)
 		return NULL;
 
+	RB_CLEAR_NODE(&cfqd->sib_node);
+
 	if (!cfqmd) {
        		cfqmd = cfq_cgroup_init_meta_data(cfqd, q);
 		if (!cfqmd) {
@@ -73,6 +108,7 @@ struct cfq_data *__cfq_cgroup_init_queue(struct request_queue *q, void *data)
 			return NULL;
 		}
 	}
+	cfq_meta_data_sibling_tree_add(cfqmd, cfqd);
 
 	return cfqd;
 }
@@ -102,11 +138,35 @@ cfq_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 /*
  * Remove device or cgroup data functions.
  */
+static void cfq_cgroup_erase_meta_data_siblings(struct cfq_meta_data *cfqmd, struct cfq_data *cfqd)
+{
+	rb_erase(&cfqd->sib_node, &cfqmd->sibling_tree);
+	cfqmd->siblings--;
+}
+
+static void cfq_exit_device_group(struct cfq_meta_data *cfqmd)
+{
+	struct rb_node *p, *n;
+	struct cfq_data *cfqd;
+
+	p =  rb_first(&cfqmd->sibling_tree);
+
+	while (p) {
+		n = rb_next(p);
+		cfqd = rb_entry(p, struct cfq_data, sib_node);
+
+		cfq_cgroup_erase_meta_data_siblings(cfqmd, cfqd);
+		__cfq_exit_data(cfqd);
+
+		p = n;
+	}
+}
+
 static void __cfq_cgroup_exit_data(struct cfq_data *cfqd)
 {
 	struct cfq_meta_data *cfqmd = cfqd->cfqmd;
 
-	__cfq_exit_data(cfqd);
+	cfq_exit_device_group(cfqmd);
 	kfree(cfqmd);
 }
 
diff --git a/include/linux/cfq-iosched.h b/include/linux/cfq-iosched.h
index e5b41da..c8879a7 100644
--- a/include/linux/cfq-iosched.h
+++ b/include/linux/cfq-iosched.h
@@ -54,6 +54,10 @@ struct cfq_driver_data {
  */
 struct cfq_meta_data {
 	struct cfq_data *elv_data;
+
+	/* device siblings */
+	struct rb_root sibling_tree;
+	unsigned int siblings;
 	
 	struct cfq_driver_data cfq_driv_d;
 };
@@ -91,6 +95,9 @@ struct cfq_data {
 
 #ifdef CONFIG_CGROUP_CFQ
 	struct cfq_meta_data *cfqmd;
+	/* sibling_tree member for cfq_meta_data */
+	struct rb_node sib_node;
+
 #else
 	struct cfq_driver_data cfq_driv_d;
 #endif