block: move elevator tags into struct elevator_resources

This patch introduces a new structure, struct elevator_resources, to
group together all elevator-related resources that share the same
lifetime. As a first step, this change moves the elevator tag pointer
from struct elv_change_ctx into the new struct elevator_resources.

Additionally, rename blk_mq_alloc_sched_tags_batch() and
blk_mq_free_sched_tags_batch() to blk_mq_alloc_sched_res_batch() and
blk_mq_free_sched_res_batch(), respectively. Introduce two new wrapper
helpers, blk_mq_alloc_sched_res() and blk_mq_free_sched_res(), around
blk_mq_alloc_sched_tags() and blk_mq_free_sched_tags().

These changes pave the way for consolidating the allocation and freeing
of elevator-specific resources into common helper functions. This
refactoring improves encapsulation and prepares the code for future
extensions, allowing additional elevator-specific data to be added to
struct elevator_resources without cluttering struct elv_change_ctx.

Subsequent patches will extend struct elevator_resources to include
other elevator-related data.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 7 insertions, 2 deletions

diff --git a/block/elevator.h b/block/elevator.h
index bad43182361e..621a63597249 100644
--- a/block/elevator.h
+++ b/block/elevator.h
@@ -32,6 +32,11 @@ struct elevator_tags {
 	struct blk_mq_tags *tags[];
 };
 
+struct elevator_resources {
+	/* holds elevator tags */
+	struct elevator_tags *et;
+};
+
 /* Holding context data for changing elevator */
 struct elv_change_ctx {
 	const char *name;
@@ -43,8 +48,8 @@ struct elv_change_ctx {
 	struct elevator_queue *new;
 	/* store elevator type */
 	struct elevator_type *type;
-	/* holds sched tags data */
-	struct elevator_tags *et;
+	/* store elevator resources */
+	struct elevator_resources res;
 };
 
 struct elevator_mq_ops {