block: look up the elevator type in elevator_switch

[Christoph Hellwig <hch@xxxxxx>]

That makes the function nicely self-contained and can be used
to avoid code duplication.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 block/elevator.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/block/elevator.c b/block/elevator.c
index a637426da56d..773b8931d874 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -591,14 +591,18 @@ static bool use_default_elevator(struct request_queue *q)
  * If switching fails, we are most likely running out of memory and not able
  * to restore the old io scheduler, so leaving the io scheduler being none.
  */
-static int elevator_switch(struct request_queue *q, struct elevator_type *new_e,
-			   struct elv_change_ctx *ctx)
+static int elevator_switch(struct request_queue *q, struct elv_change_ctx *ctx)
 {
+	struct elevator_type *new_e;
 	int ret;
 
 	WARN_ON_ONCE(q->mq_freeze_depth == 0);
 	lockdep_assert_held(&q->elevator_lock);
 
+	new_e = elevator_find_get(ctx->name);
+	if (!new_e)
+		return -EINVAL;
+
 	blk_mq_quiesce_queue(q);
 
 	if (q->elevator) {
@@ -621,6 +625,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e,
 			new_e->elevator_name);
 	}
 
+	elevator_put(new_e);
 	return ret;
 }
 
@@ -686,8 +691,6 @@ static int __elevator_change(struct request_queue *q,
 			     struct elv_change_ctx *ctx)
 {
 	const char *elevator_name = ctx->name;
-	struct elevator_type *e;
-	int ret;
 
 	lockdep_assert_held(&q->tag_set->update_nr_hwq_sema);
 
@@ -701,12 +704,7 @@ static int __elevator_change(struct request_queue *q,
 		return 0;
 	}
 
-	e = elevator_find_get(elevator_name);
-	if (!e)
-		return -EINVAL;
-	ret = elevator_switch(q, e, ctx);
-	elevator_put(e);
-	return ret;
+	return elevator_switch(q, ctx);
 }
 
 static int elevator_change(struct request_queue *q,
-- 
2.47.2


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Content-Type: text/x-patch; charset=us-ascii
Content-Disposition: attachment; filename="0002-block-fold-elevator_disable-into-elevator_switch.patch"