[PATCH 3/4] blk-wbt: pass in enum wbt_flags to get_rq_wait()

[Jens Axboe]

This is in preparation for having more write queues, in which
case we would have needed to pass in more information than just
a simple 'is_kswapd' boolean.

Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
 block/blk-wbt.c | 25 +++++++++++++++----------
 block/blk-wbt.h |  4 +++-
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 3e34b41bcefc..25d202345965 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -101,9 +101,13 @@ static bool wb_recent_wait(struct rq_wb *rwb)
        return time_before(jiffies, wb->dirty_sleep + HZ);
 }
 
-static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb, bool is_kswapd)
+static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb,
+                                         enum wbt_flags wb_acct)
 {
-       return &rwb->rq_wait[is_kswapd];
+       if (wb_acct & WBT_KSWAPD)
+               return &rwb->rq_wait[WBT_RWQ_KSWAPD];
+
+       return &rwb->rq_wait[WBT_RWQ_BG];
 }
 
 static void rwb_wake_all(struct rq_wb *rwb)
@@ -126,7 +130,7 @@ void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct)
        if (!(wb_acct & WBT_TRACKED))
                return;
 
-       rqw = get_rq_wait(rwb, wb_acct & WBT_KSWAPD);
+       rqw = get_rq_wait(rwb, wb_acct);
        inflight = atomic_dec_return(&rqw->inflight);
 
        /*
@@ -529,11 +533,12 @@ static inline bool may_queue(struct rq_wb *rwb, struct 
rq_wait *rqw,
  * Block if we will exceed our limit, or if we are currently waiting for
  * the timer to kick off queuing again.
  */
-static void __wbt_wait(struct rq_wb *rwb, unsigned long rw, spinlock_t *lock)
+static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
+                      unsigned long rw, spinlock_t *lock)
        __releases(lock)
        __acquires(lock)
 {
-       struct rq_wait *rqw = get_rq_wait(rwb, current_is_kswapd());
+       struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);
        DEFINE_WAIT(wait);
 
        if (may_queue(rwb, rqw, &wait, rw))
@@ -584,7 +589,7 @@ static inline bool wbt_should_throttle(struct rq_wb *rwb, 
struct bio *bio)
  */
 enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock)
 {
-       unsigned int ret = 0;
+       enum wbt_flags ret = 0;
 
        if (!rwb_enabled(rwb))
                return 0;
@@ -598,14 +603,14 @@ enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio 
*bio, spinlock_t *lock)
                return ret;
        }
 
-       __wbt_wait(rwb, bio->bi_opf, lock);
+       if (current_is_kswapd())
+               ret |= WBT_KSWAPD;
+
+       __wbt_wait(rwb, ret, bio->bi_opf, lock);
 
        if (!blk_stat_is_active(rwb->cb))
                rwb_arm_timer(rwb);
 
-       if (current_is_kswapd())
-               ret |= WBT_KSWAPD;
-
        return ret | WBT_TRACKED;
 }
 
diff --git a/block/blk-wbt.h b/block/blk-wbt.h
index a232c98fbf4d..8038b4a0d4ef 100644
--- a/block/blk-wbt.h
+++ b/block/blk-wbt.h
@@ -19,7 +19,9 @@ enum wbt_flags {
 };
 
 enum {
-       WBT_NUM_RWQ             = 2,
+       WBT_RWQ_BG              = 0,
+       WBT_RWQ_KSWAPD,
+       WBT_NUM_RWQ,
 };
 
 /*
-- 
2.7.4