Commit f7c4cdc7 authored by John Garry's avatar John Garry Committed by Jens Axboe
Browse files

scsi: scsi_debug: Support host tagset 



When host_max_queue is set (> 0), set the Scsi_Host.host_tagset such that
blk-mq will use a hostwide tagset over all SCSI host submission queues.

This means that we may expose all submission queues and always use the hwq
chosen by blk-mq.

And since if sdebug_host_max_queue is set, sdebug_max_queue is fixed to the
same value, we can simplify how sdebug_driver_template.can_queue is set.

Signed-off-by: default avatarJohn Garry <john.garry@huawei.com>
Tested-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Acked-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8d98416a

drivers/scsi/scsi_debug.c

+10 −18
Original line number Diff line number Diff line
@@ -4696,11 +4696,6 @@ fini: 
static struct sdebug_queue *get_queue(struct scsi_cmnd *cmnd)

{

	u16 hwq;



	if (sdebug_host_max_queue) {

		/* Provide a simple method to choose the hwq */

		hwq = smp_processor_id() % submit_queues;

	} else {

	u32 tag = blk_mq_unique_tag(cmnd->request);



	hwq = blk_mq_unique_tag_to_hwq(tag);
@@ -4708,7 +4703,7 @@ static struct sdebug_queue *get_queue(struct scsi_cmnd *cmnd) 
	pr_debug("tag=%#x, hwq=%d\n", tag, hwq);

	if (WARN_ON_ONCE(hwq >= submit_queues))

		hwq = 0;

	}



	return sdebug_q_arr + hwq;

}
@@ -7347,9 +7342,6 @@ static int sdebug_driver_probe(struct device *dev) 


	sdbg_host = to_sdebug_host(dev);



	if (sdebug_host_max_queue)

		sdebug_driver_template.can_queue = sdebug_host_max_queue;

	else

	sdebug_driver_template.can_queue = sdebug_max_queue;

	if (!sdebug_clustering)

		sdebug_driver_template.dma_boundary = PAGE_SIZE - 1;
@@ -7367,11 +7359,11 @@ static int sdebug_driver_probe(struct device *dev) 
	}

	/*

	 * Decide whether to tell scsi subsystem that we want mq. The

	 * following should give the same answer for each host. If the host

	 * has a limit of hostwide max commands, then do not set.

	 * following should give the same answer for each host.

	 */

	if (!sdebug_host_max_queue)

	hpnt->nr_hw_queues = submit_queues;

	if (sdebug_host_max_queue)

		hpnt->host_tagset = 1;



	sdbg_host->shost = hpnt;

	*((struct sdebug_host_info **)hpnt->hostdata) = sdbg_host;

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