From 532b9e11b8540eb543ebec9cba851c5691e10b5b Mon Sep 17 00:00:00 2001 From: Nilay Shroff Date: Thu, 15 May 2025 19:14:39 +0530 Subject: [PATCH] block: fix elv_update_nr_hw_queues() to reattach elevator When nr_hw_queues is updated, the elevator needs to be switched to ensure that we exit elevator and reattach it to ensure that hctx-> sched_tags is correctly allocated for the new hardware queues. However, elv_update_nr_hw_queues() currently only switches the elevator if the queue is not registered. This is incorrect, as it prevents reattaching the elevator after updating nr_hw_queues, which in turn inhibits allocation of sched_tags. Fix this by allowing the elevator switch if the queue is registered, ensuring proper reattachment and resource allocation. Fixes: 596dce110b7d ("block: simplify elevator reattachment for updating nr_hw_queues") Signed-off-by: Nilay Shroff Link: https://lore.kernel.org/r/20250515134511.548270-1-nilay@linux.ibm.com Signed-off-by: Jens Axboe --- block/elevator.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/elevator.c b/block/elevator.c index f8d72bd20610..ab22542e6cf0 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -697,7 +697,7 @@ void elv_update_nr_hw_queues(struct request_queue *q) WARN_ON_ONCE(q->mq_freeze_depth == 0); mutex_lock(&q->elevator_lock); - if (q->elevator && !blk_queue_dying(q) && !blk_queue_registered(q)) { + if (q->elevator && !blk_queue_dying(q) && blk_queue_registered(q)) { ctx.name = q->elevator->type->elevator_name; /* force to reattach elevator after nr_hw_queue is updated */