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scsi: scsi_debug: Support host tagset

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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: John Garry <john.garry@huawei.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
John Garry 2020-08-19 23:20:33 +08:00 committed by Jens Axboe
parent 8d98416a55
commit f7c4cdc712
1 changed files with 10 additions and 18 deletions
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28
drivers/scsi/scsi_debug.c
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@ -4696,19 +4696,14 @@ fini:
static struct sdebug_queue *get_queue(struct scsi_cmnd *cmnd)
{
u16 hwq;
u32 tag = blk_mq_unique_tag(cmnd->request);
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);
hwq = blk_mq_unique_tag_to_hwq(tag);
pr_debug("tag=%#x, hwq=%d\n", tag, hwq);
if (WARN_ON_ONCE(hwq >= submit_queues))
hwq = 0;
pr_debug("tag=%#x, hwq=%d\n", tag, hwq);
if (WARN_ON_ONCE(hwq >= submit_queues))
hwq = 0;
}
return sdebug_q_arr + hwq;
}
@ -7347,10 +7342,7 @@ 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;
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;
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;