[PATCH V2 14/20] block: pass elevator_queue to elv_register_queue & unregister_queue

[Ming Lei <ming.lei@xxxxxxxxxx>]

Pass elevator_queue reference to elv_register_queue() & elv_unregister_queue().

No functional change, and prepare for moving the two out of elevator
lock & freezing queue, when we need to store the old & new elevator
queue in `struct elv_change_ctx` instance, then both two can co-exist
for short while, so we have to pass the specific elevator_queue instance
to elv_register_queue & unregister_queue.

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
 block/elevator.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/block/elevator.c b/block/elevator.c
index 936d8ec9e9f0..568457e01d28 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -455,9 +455,10 @@ static const struct kobj_type elv_ktype = {
 	.release	= elevator_release,
 };
 
-static int elv_register_queue(struct request_queue *q, bool uevent)
+static int elv_register_queue(struct request_queue *q,
+			      struct elevator_queue *e,
+			      bool uevent)
 {
-	struct elevator_queue *e = q->elevator;
 	int error;
 
 	lockdep_assert_held(&q->elevator_lock);
@@ -485,10 +486,9 @@ static int elv_register_queue(struct request_queue *q, bool uevent)
 	return error;
 }
 
-static void elv_unregister_queue(struct request_queue *q)
+static void elv_unregister_queue(struct request_queue *q,
+				 struct elevator_queue *e)
 {
-	struct elevator_queue *e = q->elevator;
-
 	lockdep_assert_held(&q->elevator_lock);
 
 	if (e && test_and_clear_bit(ELEVATOR_FLAG_REGISTERED, &e->flags)) {
@@ -634,7 +634,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e,
 	blk_mq_quiesce_queue(q);
 
 	if (q->elevator) {
-		elv_unregister_queue(q);
+		elv_unregister_queue(q, q->elevator);
 		elevator_exit(q);
 	}
 
@@ -642,7 +642,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e,
 	if (ret)
 		goto out_unfreeze;
 
-	ret = elv_register_queue(q, ctx->uevent);
+	ret = elv_register_queue(q, q->elevator, ctx->uevent);
 	if (ret) {
 		elevator_exit(q);
 		goto out_unfreeze;
@@ -667,7 +667,7 @@ static void elevator_disable(struct request_queue *q)
 
 	blk_mq_quiesce_queue(q);
 
-	elv_unregister_queue(q);
+	elv_unregister_queue(q, q->elevator);
 	elevator_exit(q);
 	blk_queue_flag_clear(QUEUE_FLAG_SQ_SCHED, q);
 	q->elevator = NULL;
-- 
2.47.0