blk-wbt: allow reset of default latency through sysfs
Allow a write of '-1' to reset the default latency target for
a given device. This removes knowledge of the different default
settings for rotational vs non-rotational from user space.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-wbt.h b/block/blk-wbt.h
index 44dc217..9dfc88a 100644
--- a/block/blk-wbt.h
+++ b/block/blk-wbt.h
@@ -110,6 +110,8 @@ void wbt_disable(struct rq_wb *);
void wbt_set_queue_depth(struct rq_wb *, unsigned int);
void wbt_set_write_cache(struct rq_wb *, bool);
+u64 wbt_default_latency_nsec(struct request_queue *);
+
#else
static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
@@ -148,6 +150,10 @@ static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
{
}
+static inline u64 wbt_default_latency_nsec(struct request_queue *q)
+{
+ return 0;
+}
#endif /* CONFIG_BLK_WBT */