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-rw-r--r--block/blk-rq-qos.c14
-rw-r--r--block/blk-rq-qos.h4
-rw-r--r--block/blk-wbt.c6
3 files changed, 15 insertions, 9 deletions
diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c
index 61b635bc2a31..656460636ad3 100644
--- a/block/blk-rq-qos.c
+++ b/block/blk-rq-qos.c
@@ -160,24 +160,27 @@ bool rq_depth_calc_max_depth(struct rq_depth *rqd)
return ret;
}
-void rq_depth_scale_up(struct rq_depth *rqd)
+/* Returns true on success and false if scaling up wasn't possible */
+bool rq_depth_scale_up(struct rq_depth *rqd)
{
/*
* Hit max in previous round, stop here
*/
if (rqd->scaled_max)
- return;
+ return false;
rqd->scale_step--;
rqd->scaled_max = rq_depth_calc_max_depth(rqd);
+ return true;
}
/*
* Scale rwb down. If 'hard_throttle' is set, do it quicker, since we
- * had a latency violation.
+ * had a latency violation. Returns true on success and returns false if
+ * scaling down wasn't possible.
*/
-void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle)
+bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle)
{
/*
* Stop scaling down when we've hit the limit. This also prevents
@@ -185,7 +188,7 @@ void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle)
* keep up.
*/
if (rqd->max_depth == 1)
- return;
+ return false;
if (rqd->scale_step < 0 && hard_throttle)
rqd->scale_step = 0;
@@ -194,6 +197,7 @@ void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle)
rqd->scaled_max = false;
rq_depth_calc_max_depth(rqd);
+ return true;
}
struct rq_qos_wait_data {
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 08a09dbe0f4b..e8cb68f6958a 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -130,8 +130,8 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data,
acquire_inflight_cb_t *acquire_inflight_cb,
cleanup_cb_t *cleanup_cb);
bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
-void rq_depth_scale_up(struct rq_depth *rqd);
-void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
+bool rq_depth_scale_up(struct rq_depth *rqd);
+bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
bool rq_depth_calc_max_depth(struct rq_depth *rqd);
void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 8af553a0ba00..8641ba9793c5 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -308,7 +308,8 @@ static void calc_wb_limits(struct rq_wb *rwb)
static void scale_up(struct rq_wb *rwb)
{
- rq_depth_scale_up(&rwb->rq_depth);
+ if (!rq_depth_scale_up(&rwb->rq_depth))
+ return;
calc_wb_limits(rwb);
rwb->unknown_cnt = 0;
rwb_wake_all(rwb);
@@ -317,7 +318,8 @@ static void scale_up(struct rq_wb *rwb)
static void scale_down(struct rq_wb *rwb, bool hard_throttle)
{
- rq_depth_scale_down(&rwb->rq_depth, hard_throttle);
+ if (!rq_depth_scale_down(&rwb->rq_depth, hard_throttle))
+ return;
calc_wb_limits(rwb);
rwb->unknown_cnt = 0;
rwb_trace_step(rwb, "scale down");