Instead of iterating all deferred commands in the submission queue
structures, use blk_mq_tagset_busy_iter(), which is a standard API for
this.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20230327074310.1862889-8-john.g.garry@oracle.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>