FROMLIST: blk-mq: Swap two calls in blk_mq_exit_queue()

If a tag set is shared across request queues (e.g. SCSI LUNs) then the
block layer core keeps track of the number of active request queues in
tags->active_queues. blk_mq_tag_busy() and blk_mq_tag_idle() update that
atomic counter if the hctx flag BLK_MQ_F_TAG_QUEUE_SHARED is set. Make
sure that blk_mq_exit_queue() calls blk_mq_tag_idle() before that flag is
cleared by blk_mq_del_queue_tag_set().

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Fixes: 0d2602ca ("blk-mq: improve support for shared tags maps")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Bug: 181696921
Link: https://lore.kernel.org/linux-block/d1b1f123-9b47-8805-0b86-2fa9f6b19bb5@kernel.dk/T/#ma8a01d264c59074d3f9b69f833ffe408592cf837


Signed-off-by: Bart Van Assche <bvanassche@google.com>
Change-Id: I3f9ca00fbefec97d1e3c9df85365be0265b8cec6