On 9/19/2014 3:57 PM, Bart Van Assche wrote:
> 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.
>
I think this patch should be squashed with passing LLD hctx patch (in
whatever form it ends up).
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