blk-throttle: rename throtl_rb_root to throtl_service_queue

throtl_rb_root will be expanded to cover more roles for hierarchy
support.  Rename it to throtl_service_queue and make its fields more
descriptive.

* rb		-> pending_tree
* left		-> first_pending
* count		-> nr_pending
* min_disptime	-> first_pending_disptime

This patch is purely cosmetic.

Signed-off-by: Tejun Heo <tj@kernel.org
Acked-by: Vivek Goyal <vgoyal@redhat.com>

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index dbeef303f27b685a04ead12f0f9e2b9769023105..b279110ba287feb79fd9e3b82e8603f8aac320e2 100644 (file)
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -26,15 +26,15 @@ static struct blkcg_policy blkcg_policy_throtl;
 /* A workqueue to queue throttle related work */
 static struct workqueue_struct *kthrotld_workqueue;
 
-struct throtl_rb_root {
-       struct rb_root rb;
-       struct rb_node *left;
-       unsigned int count;
-       unsigned long min_disptime;
+struct throtl_service_queue {
+       struct rb_root          pending_tree;   /* RB tree of active tgs */
+       struct rb_node          *first_pending; /* first node in the tree */
+       unsigned int            nr_pending;     /* # queued in the tree */
+       unsigned long           first_pending_disptime; /* disptime of the first tg */
 };
 
-#define THROTL_RB_ROOT (struct throtl_rb_root) { .rb = RB_ROOT, .left = NULL, \
-                       .count = 0, .min_disptime = 0}
+#define THROTL_SERVICE_QUEUE_INITIALIZER                               \
+       (struct throtl_service_queue){ .pending_tree = RB_ROOT }
 
 #define rb_entry_tg(node)      rb_entry((node), struct throtl_grp, rb_node)
 
@@ -50,7 +50,7 @@ struct throtl_grp {
        /* must be the first member */
        struct blkg_policy_data pd;
 
-       /* active throtl group service_tree member */
+       /* active throtl group service_queue member */
        struct rb_node rb_node;
 
        /*
@@ -93,7 +93,7 @@ struct throtl_grp {
 struct throtl_data
 {
        /* service tree for active throtl groups */
-       struct throtl_rb_root tg_service_tree;
+       struct throtl_service_queue service_queue;
 
        struct request_queue *queue;
 
@@ -296,17 +296,17 @@ static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
        return tg;
 }
 
-static struct throtl_grp *throtl_rb_first(struct throtl_rb_root *root)
+static struct throtl_grp *throtl_rb_first(struct throtl_service_queue *sq)
 {
        /* Service tree is empty */
-       if (!root->count)
+       if (!sq->nr_pending)
                return NULL;
 
-       if (!root->left)
-               root->left = rb_first(&root->rb);
+       if (!sq->first_pending)
+               sq->first_pending = rb_first(&sq->pending_tree);
 
-       if (root->left)
-               return rb_entry_tg(root->left);
+       if (sq->first_pending)
+               return rb_entry_tg(sq->first_pending);
 
        return NULL;
 }
@@ -317,29 +317,29 @@ static void rb_erase_init(struct rb_node *n, struct rb_root *root)
        RB_CLEAR_NODE(n);
 }
 
-static void throtl_rb_erase(struct rb_node *n, struct throtl_rb_root *root)
+static void throtl_rb_erase(struct rb_node *n, struct throtl_service_queue *sq)
 {
-       if (root->left == n)
-               root->left = NULL;
-       rb_erase_init(n, &root->rb);
-       --root->count;
+       if (sq->first_pending == n)
+               sq->first_pending = NULL;
+       rb_erase_init(n, &sq->pending_tree);
+       --sq->nr_pending;
 }
 
-static void update_min_dispatch_time(struct throtl_rb_root *st)
+static void update_min_dispatch_time(struct throtl_service_queue *sq)
 {
        struct throtl_grp *tg;
 
-       tg = throtl_rb_first(st);
+       tg = throtl_rb_first(sq);
        if (!tg)
                return;
 
-       st->min_disptime = tg->disptime;
+       sq->first_pending_disptime = tg->disptime;
 }
 
-static void
-tg_service_tree_add(struct throtl_rb_root *st, struct throtl_grp *tg)
+static void tg_service_queue_add(struct throtl_service_queue *sq,
+                                struct throtl_grp *tg)
 {
-       struct rb_node **node = &st->rb.rb_node;
+       struct rb_node **node = &sq->pending_tree.rb_node;
        struct rb_node *parent = NULL;
        struct throtl_grp *__tg;
        unsigned long key = tg->disptime;
@@ -358,19 +358,19 @@ tg_service_tree_add(struct throtl_rb_root *st, struct throtl_grp *tg)
        }
 
        if (left)
-               st->left = &tg->rb_node;
+               sq->first_pending = &tg->rb_node;
 
        rb_link_node(&tg->rb_node, parent, node);
-       rb_insert_color(&tg->rb_node, &st->rb);
+       rb_insert_color(&tg->rb_node, &sq->pending_tree);
 }
 
 static void __throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
 {
-       struct throtl_rb_root *st = &td->tg_service_tree;
+       struct throtl_service_queue *sq = &td->service_queue;
 
-       tg_service_tree_add(st, tg);
+       tg_service_queue_add(sq, tg);
        throtl_mark_tg_on_rr(tg);
-       st->count++;
+       sq->nr_pending++;
 }
 
 static void throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
@@ -381,7 +381,7 @@ static void throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
 
 static void __throtl_dequeue_tg(struct throtl_data *td, struct throtl_grp *tg)
 {
-       throtl_rb_erase(&tg->rb_node, &td->tg_service_tree);
+       throtl_rb_erase(&tg->rb_node, &td->service_queue);
        throtl_clear_tg_on_rr(tg);
 }
 
@@ -403,18 +403,18 @@ static void throtl_schedule_delayed_work(struct throtl_data *td,
 
 static void throtl_schedule_next_dispatch(struct throtl_data *td)
 {
-       struct throtl_rb_root *st = &td->tg_service_tree;
+       struct throtl_service_queue *sq = &td->service_queue;
 
        /* any pending children left? */
-       if (!st->count)
+       if (!sq->nr_pending)
                return;
 
-       update_min_dispatch_time(st);
+       update_min_dispatch_time(sq);
 
-       if (time_before_eq(st->min_disptime, jiffies))
+       if (time_before_eq(sq->first_pending_disptime, jiffies))
                throtl_schedule_delayed_work(td, 0);
        else
-               throtl_schedule_delayed_work(td, (st->min_disptime - jiffies));
+               throtl_schedule_delayed_work(td, sq->first_pending_disptime - jiffies);
 }
 
 static inline void
@@ -794,10 +794,10 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
 {
        unsigned int nr_disp = 0;
        struct throtl_grp *tg;
-       struct throtl_rb_root *st = &td->tg_service_tree;
+       struct throtl_service_queue *sq = &td->service_queue;
 
        while (1) {
-               tg = throtl_rb_first(st);
+               tg = throtl_rb_first(sq);
 
                if (!tg)
                        break;
@@ -1145,7 +1145,7 @@ void blk_throtl_drain(struct request_queue *q)
        __releases(q->queue_lock) __acquires(q->queue_lock)
 {
        struct throtl_data *td = q->td;
-       struct throtl_rb_root *st = &td->tg_service_tree;
+       struct throtl_service_queue *sq = &td->service_queue;
        struct throtl_grp *tg;
        struct bio_list bl;
        struct bio *bio;
@@ -1154,7 +1154,7 @@ void blk_throtl_drain(struct request_queue *q)
 
        bio_list_init(&bl);
 
-       while ((tg = throtl_rb_first(st))) {
+       while ((tg = throtl_rb_first(sq))) {
                throtl_dequeue_tg(td, tg);
 
                while ((bio = bio_list_peek(&tg->bio_lists[READ])))
@@ -1179,7 +1179,7 @@ int blk_throtl_init(struct request_queue *q)
        if (!td)
                return -ENOMEM;
 
-       td->tg_service_tree = THROTL_RB_ROOT;
+       td->service_queue = THROTL_SERVICE_QUEUE_INITIALIZER;
        INIT_DELAYED_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn);
 
        q->td = td;