Allow a SCSI LLD to declare how many hardware queues it supports
by setting Scsi_Host.nr_hw_queues before calling scsi_add_host().
Note: it is assumed that each hardware queue has a queue depth of
shost->can_queue. In other words, the total queue depth per host
is (number of hardware queues) * (shost->can_queue).
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
---
drivers/scsi/scsi_lib.c | 2 +-
include/scsi/scsi_host.h | 4 ++++
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index d837dc1..b0b6117 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2071,7 +2071,7 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
memset(&shost->tag_set, 0, sizeof(shost->tag_set));
shost->tag_set.ops = &scsi_mq_ops;
- shost->tag_set.nr_hw_queues = 1;
+ shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
shost->tag_set.queue_depth = shost->can_queue;
shost->tag_set.cmd_size = cmd_size;
shost->tag_set.numa_node = NUMA_NO_NODE;
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index ba20347..0a867d9 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -638,6 +638,10 @@ struct Scsi_Host {
short unsigned int sg_prot_tablesize;
unsigned int max_sectors;
unsigned long dma_boundary;
+ /*
+ * In scsi-mq mode, the number of hardware queues supported by the LLD.
+ */
+ unsigned nr_hw_queues;
/*
* Used to assign serial numbers to the cmds.
* Protected by the host lock.
--
1.8.4.5
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