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Subject[PATCH] blk-throttle: clean up codes that can't be reached
Date
From: Yu Kuai <yukuai3@huawei.com>

While doing code coverage testing while CONFIG_BLK_DEV_THROTTLING_LOW is
disabled, we found that there are many codes can never be reached.

This patch move such codes inside "#ifdef CONFIG_BLK_DEV_THROTTLING_LOW".

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
block/blk-throttle.c | 90 +++++++++++++++++++++++++++-----------------
1 file changed, 56 insertions(+), 34 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 9f5fe62afff9..667b2958471a 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1673,6 +1673,40 @@ struct blkcg_policy blkcg_policy_throtl = {
.pd_free_fn = throtl_pd_free,
};

+void blk_throtl_cancel_bios(struct request_queue *q)
+{
+ struct cgroup_subsys_state *pos_css;
+ struct blkcg_gq *blkg;
+
+ spin_lock_irq(&q->queue_lock);
+ /*
+ * queue_lock is held, rcu lock is not needed here technically.
+ * However, rcu lock is still held to emphasize that following
+ * path need RCU protection and to prevent warning from lockdep.
+ */
+ rcu_read_lock();
+ blkg_for_each_descendant_post(blkg, pos_css, q->root_blkg) {
+ struct throtl_grp *tg = blkg_to_tg(blkg);
+ struct throtl_service_queue *sq = &tg->service_queue;
+
+ /*
+ * Set the flag to make sure throtl_pending_timer_fn() won't
+ * stop until all throttled bios are dispatched.
+ */
+ blkg_to_tg(blkg)->flags |= THROTL_TG_CANCELING;
+ /*
+ * Update disptime after setting the above flag to make sure
+ * throtl_select_dispatch() won't exit without dispatching.
+ */
+ tg_update_disptime(tg);
+
+ throtl_schedule_pending_timer(sq, jiffies + 1);
+ }
+ rcu_read_unlock();
+ spin_unlock_irq(&q->queue_lock);
+}
+
+#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg)
{
unsigned long rtime = jiffies, wtime = jiffies;
@@ -1777,39 +1811,6 @@ static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg)
return false;
}

-void blk_throtl_cancel_bios(struct request_queue *q)
-{
- struct cgroup_subsys_state *pos_css;
- struct blkcg_gq *blkg;
-
- spin_lock_irq(&q->queue_lock);
- /*
- * queue_lock is held, rcu lock is not needed here technically.
- * However, rcu lock is still held to emphasize that following
- * path need RCU protection and to prevent warning from lockdep.
- */
- rcu_read_lock();
- blkg_for_each_descendant_post(blkg, pos_css, q->root_blkg) {
- struct throtl_grp *tg = blkg_to_tg(blkg);
- struct throtl_service_queue *sq = &tg->service_queue;
-
- /*
- * Set the flag to make sure throtl_pending_timer_fn() won't
- * stop until all throttled bios are dispatched.
- */
- blkg_to_tg(blkg)->flags |= THROTL_TG_CANCELING;
- /*
- * Update disptime after setting the above flag to make sure
- * throtl_select_dispatch() won't exit without dispatching.
- */
- tg_update_disptime(tg);
-
- throtl_schedule_pending_timer(sq, jiffies + 1);
- }
- rcu_read_unlock();
- spin_unlock_irq(&q->queue_lock);
-}
-
static bool throtl_can_upgrade(struct throtl_data *td,
struct throtl_grp *this_tg)
{
@@ -2005,7 +2006,6 @@ static void blk_throtl_update_idletime(struct throtl_grp *tg)
tg->checked_last_finish_time = last_finish_time;
}

-#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
static void throtl_update_latency_buckets(struct throtl_data *td)
{
struct avg_latency_bucket avg_latency[2][LATENCY_BUCKET_SIZE];
@@ -2086,6 +2086,28 @@ static void throtl_update_latency_buckets(struct throtl_data *td)
static inline void throtl_update_latency_buckets(struct throtl_data *td)
{
}
+
+static void blk_throtl_update_idletime(struct throtl_grp *tg)
+{
+}
+
+static void throtl_downgrade_check(struct throtl_grp *tg)
+{
+}
+
+static void throtl_upgrade_check(struct throtl_grp *tg)
+{
+}
+
+static bool throtl_can_upgrade(struct throtl_data *td,
+ struct throtl_grp *this_tg)
+{
+ return false;
+}
+
+static void throtl_upgrade_state(struct throtl_data *td)
+{
+}
#endif

bool __blk_throtl_bio(struct bio *bio)
--
2.31.1
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