block: fold elevator_disable into elevator_switch

[Christoph Hellwig <hch@xxxxxx>]

This removes duplicate code, and keeps the callers tidy.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 block/elevator.c | 59 ++++++++++++++++--------------------------------
 1 file changed, 20 insertions(+), 39 deletions(-)

diff --git a/block/elevator.c b/block/elevator.c
index 773b8931d874..59ff0abde920 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -593,15 +593,17 @@ static bool use_default_elevator(struct request_queue *q)
  */
 static int elevator_switch(struct request_queue *q, struct elv_change_ctx *ctx)
 {
-	struct elevator_type *new_e;
-	int ret;
+	struct elevator_type *new_e = NULL;
+	int ret = 0;
 
 	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;
+	if (strncmp(ctx->name, "none", 4)) {
+		new_e = elevator_find_get(ctx->name);
+		if (!new_e)
+			return -EINVAL;
+	}
 
 	blk_mq_quiesce_queue(q);
 
@@ -610,12 +612,17 @@ static int elevator_switch(struct request_queue *q, struct elv_change_ctx *ctx)
 		__elevator_exit(q);
 	}
 
-	ret = blk_mq_init_sched(q, new_e);
-	if (ret)
-		goto out_unfreeze;
-
-	ctx->new = q->elevator;
-	blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name);
+	if (new_e) {
+		ret = blk_mq_init_sched(q, new_e);
+		if (ret)
+			goto out_unfreeze;
+		ctx->new = q->elevator;
+	} else {
+		blk_queue_flag_clear(QUEUE_FLAG_SQ_SCHED, q);
+		q->elevator = NULL;
+		q->nr_requests = q->tag_set->queue_depth;
+	}
+	blk_add_trace_msg(q, "elv switch: %s", ctx->name);
 
 out_unfreeze:
 	blk_mq_unquiesce_queue(q);
@@ -625,28 +632,11 @@ static int elevator_switch(struct request_queue *q, struct elv_change_ctx *ctx)
 			new_e->elevator_name);
 	}
 
-	elevator_put(new_e);
+	if (new_e)
+		elevator_put(new_e);
 	return ret;
 }
 
-static void elevator_disable(struct request_queue *q,
-			     struct elv_change_ctx *ctx)
-{
-	WARN_ON_ONCE(q->mq_freeze_depth == 0);
-	lockdep_assert_held(&q->elevator_lock);
-
-	blk_mq_quiesce_queue(q);
-
-	ctx->old = q->elevator;
-	__elevator_exit(q);
-	blk_queue_flag_clear(QUEUE_FLAG_SQ_SCHED, q);
-	q->elevator = NULL;
-	q->nr_requests = q->tag_set->queue_depth;
-	blk_add_trace_msg(q, "elv switch: none");
-
-	blk_mq_unquiesce_queue(q);
-}
-
 static void elv_exit_and_release(struct request_queue *q)
 {
 	struct elevator_queue *e;
@@ -690,20 +680,11 @@ static int elevator_change_done(struct request_queue *q,
 static int __elevator_change(struct request_queue *q,
 			     struct elv_change_ctx *ctx)
 {
-	const char *elevator_name = ctx->name;
-
 	lockdep_assert_held(&q->tag_set->update_nr_hwq_sema);
 
 	/* Make sure queue is not in the middle of being removed */
 	if (!ctx->init && !blk_queue_registered(q))
 		return -ENOENT;
-
-	if (!strncmp(elevator_name, "none", 4)) {
-		if (q->elevator)
-			elevator_disable(q, ctx);
-		return 0;
-	}
-
 	return elevator_switch(q, ctx);
 }
 
-- 
2.47.2


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Content-Type: text/x-patch; charset=us-ascii
Content-Disposition: attachment; filename="0003-block-remove-__elevator_change.patch"