cfq-iosched: Get rid of st->active

When a cfq group is running, it won't be dequeued from service tree, so
there's no need to store the active one in st->active. Just gid rid of it.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 73a5862..e18d316 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -87,7 +87,6 @@ struct cfq_rb_root {
        unsigned count;
        unsigned total_weight;
        u64 min_vdisktime;
-       struct rb_node *active;
 };
 #define CFQ_RB_ROOT    (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \
                        .count = 0, .min_vdisktime = 0, }
@@ -563,11 +562,6 @@ static void update_min_vdisktime(struct cfq_rb_root *st)
        u64 vdisktime = st->min_vdisktime;
        struct cfq_group *cfqg;
 
-       if (st->active) {
-               cfqg = rb_entry_cfqg(st->active);
-               vdisktime = cfqg->vdisktime;
-       }
-
        if (st->left) {
                cfqg = rb_entry_cfqg(st->left);
                vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
@@ -894,9 +888,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
        struct cfq_rb_root *st = &cfqd->grp_service_tree;
 
-       if (st->active == &cfqg->rb_node)
-               st->active = NULL;
-
        BUG_ON(cfqg->nr_cfqq < 1);
        cfqg->nr_cfqq--;
 
@@ -1095,7 +1086,7 @@ static void cfq_put_cfqg(struct cfq_group *cfqg)
        if (!atomic_dec_and_test(&cfqg->ref))
                return;
        for_each_cfqg_st(cfqg, i, j, st)
-               BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL);
+               BUG_ON(!RB_EMPTY_ROOT(&st->rb));
        kfree(cfqg);
 }
 
@@ -1687,9 +1678,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        if (cfqq == cfqd->active_queue)
                cfqd->active_queue = NULL;
 
-       if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active)
-               cfqd->grp_service_tree.active = NULL;
-
        if (cfqd->active_cic) {
                put_io_context(cfqd->active_cic->ioc);
                cfqd->active_cic = NULL;
@@ -2199,7 +2187,6 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
        if (RB_EMPTY_ROOT(&st->rb))
                return NULL;
        cfqg = cfq_rb_first_group(st);
-       st->active = &cfqg->rb_node;
        update_min_vdisktime(st);
        return cfqg;
 }