block: pass elevator_queue to elv_register_queue & unregister_queue

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 exact elevator_queue instance
to elv_register_queue & unregister_queue.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250505141805.2751237-18-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/elevator.c b/block/elevator.c
index 540542cee21c0bd8b29ac4848e2d58c6efd25e34..eb7140a678d5d0e87a5cb060a268b451a52dc60b 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -458,9 +458,10 @@ 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);
@@ -488,10 +489,9 @@ 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)) {
@@ -584,7 +584,7 @@ static int elevator_switch(struct request_queue *q, struct elv_change_ctx *ctx)
        blk_mq_quiesce_queue(q);
 
        if (q->elevator) {
-               elv_unregister_queue(q);
+               elv_unregister_queue(q, q->elevator);
                elevator_exit(q);
        }
 
@@ -592,7 +592,7 @@ static int elevator_switch(struct request_queue *q, struct elv_change_ctx *ctx)
                ret = blk_mq_init_sched(q, new_e);
                if (ret)
                        goto out_unfreeze;
-               ret = elv_register_queue(q, !ctx->no_uevent);
+               ret = elv_register_queue(q, q->elevator, !ctx->no_uevent);
                if (ret) {
                        elevator_exit(q);
                        goto out_unfreeze;