!1378 [sync] PR-1295: blk-wbt: don't show valid wbt_lat_usec in

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/1295 
 
PR sync from: Li Lingfeng <lilingfeng3@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/OFH6G7EUCRF236P635HQ5LEDXVZ4AEJJ/ 
Yu Kuai (2):
  blk-wbt: make enable_state more accurate
  blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabled


-- 
2.31.1
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1378 

Reviewed-by: Yu Kuai <yukuai3@huawei.com> 
Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

block/blk-sysfs.c

@@ -461,6 +461,9 @@ static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 	if (!wbt_rq_qos(q))
 		return -EINVAL;
 
+	if (wbt_disabled(q))
+		return sprintf(page, "0\n");
+
 	return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 }
 

block/blk-wbt.c

@@ -419,6 +419,14 @@ static void wbt_update_limits(struct rq_wb *rwb)
 	rwb_wake_all(rwb);
 }
 
+bool wbt_disabled(struct request_queue *q)
+{
+	struct rq_qos *rqos = wbt_rq_qos(q);
+
+	return !rqos || RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT ||
+	       RQWB(rqos)->enable_state == WBT_STATE_OFF_MANUAL;
+}
+
 u64 wbt_get_min_lat(struct request_queue *q)
 {
 	struct rq_qos *rqos = wbt_rq_qos(q);
@@ -432,8 +440,13 @@ void wbt_set_min_lat(struct request_queue *q, u64 val)
 	struct rq_qos *rqos = wbt_rq_qos(q);
 	if (!rqos)
 		return;
+
 	RQWB(rqos)->min_lat_nsec = val;
-	RQWB(rqos)->enable_state = WBT_STATE_ON_MANUAL;
+	if (val)
+		RQWB(rqos)->enable_state = WBT_STATE_ON_MANUAL;
+	else
+		RQWB(rqos)->enable_state = WBT_STATE_OFF_MANUAL;
+
 	wbt_update_limits(RQWB(rqos));
 }
 

block/blk-wbt.h

@@ -28,13 +28,15 @@ enum {
 };
 
 /*
- * Enable states. Either off, or on by default (done at init time),
- * or on through manual setup in sysfs.
+ * If current state is WBT_STATE_ON/OFF_DEFAULT, it can be covered to any other
+ * state, if current state is WBT_STATE_ON/OFF_MANUAL, it can only be covered
+ * to WBT_STATE_OFF/ON_MANUAL.
  */
 enum {
-	WBT_STATE_ON_DEFAULT	= 1,
-	WBT_STATE_ON_MANUAL	= 2,
-	WBT_STATE_OFF_DEFAULT
+	WBT_STATE_ON_DEFAULT	= 1,	/* on by default */
+	WBT_STATE_ON_MANUAL	= 2,	/* on manually by sysfs */
+	WBT_STATE_OFF_DEFAULT	= 3,	/* off by default */
+	WBT_STATE_OFF_MANUAL	= 4,	/* off manually by sysfs */
 };
 
 struct rq_wb {
@@ -94,6 +96,7 @@ void wbt_enable_default(struct request_queue *);
 
 u64 wbt_get_min_lat(struct request_queue *q);
 void wbt_set_min_lat(struct request_queue *q, u64 val);
+bool wbt_disabled(struct request_queue *);
 
 void wbt_set_write_cache(struct request_queue *, bool);
 
@@ -128,6 +131,10 @@ static inline u64 wbt_default_latency_nsec(struct request_queue *q)
 {
 	return 0;
 }
+static inline bool wbt_disabled(struct request_queue *q)
+{
+	return true;
+}
 
 #endif /* CONFIG_BLK_WBT */