On Wed, Apr 20 2005, James Bottomley wrote: > On Wed, 2005-04-20 at 08:15 +0900, Tejun Heo wrote: > > - * Insert this command at the head of the queue for it's device. > > - * It will go before all other commands that are already in the queue. > > - * > > - * NOTE: there is magic here about the way the queue is plugged if > > - * we have no outstanding commands. > > - * > > - * Although this *doesn't* plug the queue, it does call the request > > - * function. The SCSI request function detects the blocked condition > > - * and plugs the queue appropriately. > > This comment still looks appropriate to me ... why do you want to remove > it? > > > + * Requeue the command. > > */ > > - blk_insert_request(device->request_queue, cmd->request, 1, cmd, 1); > > + spin_lock_irqsave(q->queue_lock, flags); > > + blk_requeue_request(q, cmd->request); > > + spin_unlock_irqrestore(q->queue_lock, flags); > > + > > + scsi_run_queue(q); > > Really, wouldn't it be much more efficient simply to call blk_run_queue > ()? since the blocked flags were set above, that's pretty much what > scsi_run_queue() collapses to. I wondered about this action recently myself. What is the point in requeueing this request, only to call scsi_run_queue() -> blk_run_queue() -> issue same request. If the point really is to reissue the request immediately, I can think of many ways more efficient than this :-) -- Jens Axboe - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
