block: don't grab elevator lock during queue initialization

block: don't grab elevator lock during queue initialization

->elevator_lock depends on queue freeze lock, see block/blk-sysfs.c.

queue freeze lock depends on fs_reclaim.

So don't grab elevator lock during queue initialization which needs to
call kmalloc(GFP_KERNEL), and we can cut the dependency between
->elevator_lock and fs_reclaim, then the lockdep warning can be killed.

This way is safe because elevator setting isn't ready to run during
queue initialization.

There isn't such issue in __blk_mq_update_nr_hw_queues() because
memalloc_noio_save() is called before acquiring elevator lock.

Fixes the following lockdep warning:

https://lore.kernel.org/linux-block/67e6b425.050a0220.2f068f.007b.GAE@google.com/

Reported-by: syzbot+4c7e0f9b94ad65811efb@syzkaller.appspotmail.com
Cc: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250403105402.1334206-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>