[PATCH v6 10/12] block: Change the runtime power management approach (1/2)

[Bart Van Assche]

Instead of scheduling runtime resume of a request queue after a
request has been queued, schedule asynchronous resume during request
allocation. The new pm_request_resume() calls occur after
blk_queue_enter() has increased the q_usage_counter request queue
member. This change is needed for a later patch that will make request
allocation block while the queue status is not RPM_ACTIVE.

Signed-off-by: Bart Van Assche <bart.vanass...@wdc.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Ming Lei <ming....@redhat.com>
Cc: Jianchao Wang <jianchao.w.w...@oracle.com>
Cc: Hannes Reinecke <h...@suse.com>
Cc: Johannes Thumshirn <jthumsh...@suse.de>
Cc: Alan Stern <st...@rowland.harvard.edu>
---
 block/blk-core.c | 2 ++
 block/blk-mq.c   | 2 ++
 block/elevator.c | 1 -
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 59dd98585eb0..f30545fb2de2 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -972,6 +972,8 @@ int blk_queue_enter(struct request_queue *q, 
blk_mq_req_flags_t flags)
                if (success)
                        return 0;
 
+               blk_pm_request_resume(q);
+
                if (flags & BLK_MQ_REQ_NOWAIT)
                        return -EBUSY;
 
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2a0eb058ba5a..24439735f20b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -33,6 +33,7 @@
 #include "blk-mq.h"
 #include "blk-mq-debugfs.h"
 #include "blk-mq-tag.h"
+#include "blk-pm.h"
 #include "blk-stat.h"
 #include "blk-mq-sched.h"
 #include "blk-rq-qos.h"
@@ -473,6 +474,7 @@ static void __blk_mq_free_request(struct request *rq)
        struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
        const int sched_tag = rq->internal_tag;
 
+       blk_pm_mark_last_busy(rq);
        if (rq->tag != -1)
                blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
        if (sched_tag != -1)
diff --git a/block/elevator.c b/block/elevator.c
index 00c5d8dbce16..4c15f0240c99 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -601,7 +601,6 @@ void __elv_add_request(struct request_queue *q, struct 
request *rq, int where)
        trace_block_rq_insert(q, rq);
 
        blk_pm_add_request(q, rq);
-       blk_pm_request_resume(q);
 
        rq->q = q;
 
-- 
2.18.0