blkcg: add request_queue->root_blkg
With per-queue policy activation, root blkg creation will be moved to
blkcg core. Add q->root_blkg in preparation. For blk-throtl, this
replaces throtl_data->root_tg; however, cfq needs to keep
cfqd->root_group for !CONFIG_CFQ_GROUP_IOSCHED.
This is to prepare for per-queue policy activation and doesn't cause
any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 6f1bfdf..8c520fa 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -97,7 +97,6 @@
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
- struct throtl_grp *root_tg;
struct request_queue *queue;
/* Total Number of queued bios on READ and WRITE lists */
@@ -131,6 +130,11 @@
return pdata_to_blkg(tg);
}
+static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
+{
+ return blkg_to_tg(td->queue->root_blkg);
+}
+
enum tg_state_flags {
THROTL_TG_FLAG_on_rr = 0, /* on round-robin busy list */
};
@@ -261,7 +265,7 @@
* Avoid lookup in this case
*/
if (blkcg == &blkio_root_cgroup)
- return td->root_tg;
+ return td_root_tg(td);
return blkg_to_tg(blkg_lookup(blkcg, td->queue));
}
@@ -277,7 +281,7 @@
* Avoid lookup in this case
*/
if (blkcg == &blkio_root_cgroup) {
- tg = td->root_tg;
+ tg = td_root_tg(td);
} else {
struct blkio_group *blkg;
@@ -287,7 +291,7 @@
if (!IS_ERR(blkg))
tg = blkg_to_tg(blkg);
else if (!blk_queue_dead(q))
- tg = td->root_tg;
+ tg = td_root_tg(td);
}
return tg;
@@ -1245,12 +1249,12 @@
blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
if (!IS_ERR(blkg))
- td->root_tg = blkg_to_tg(blkg);
+ q->root_blkg = blkg;
spin_unlock_irq(q->queue_lock);
rcu_read_unlock();
- if (!td->root_tg) {
+ if (!q->root_blkg) {
kfree(td);
return -ENOMEM;
}