[RFC PATCH 2/3] nvmet: rdma: utilize ib_device capability for setting max_queue_size

[Sagi Grimberg]

> Respond with the smaller value between 1024 and the ib_device's
> max_qp_wr as the RDMA max queue size.
> 
> Signed-off-by: Guixin Liu <kanie at linux.alibaba.com>
> ---
>   drivers/nvme/target/rdma.c | 7 ++++++-
>   include/linux/nvme-rdma.h  | 2 ++
>   2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 8a728c5..c3884dd 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
> @@ -2002,7 +2002,12 @@ static u8 nvmet_rdma_get_mdts(const struct nvmet_ctrl *ctrl)
>   
>   static u16 nvmet_rdma_get_max_queue_size(const struct nvmet_sq *nvmet_sq)
>   {
> -	return NVME_RDMA_MAX_QUEUE_SIZE;
> +	struct nvmet_rdma_queue *queue =
> +		container_of(nvmet_sq, struct nvmet_rdma_queue, nvme_sq);
> +	int max_qp_wr = queue->dev->device->attrs.max_qp_wr;
> +
> +	return (u16)min_t(int, NVMET_QUEUE_SIZE,
> +			  max_qp_wr / (NVME_RDMA_SEND_WR_FACTOR + 1));
>   }

Should be folded to prev patch

>   
>   static const struct nvmet_fabrics_ops nvmet_rdma_ops = {
> diff --git a/include/linux/nvme-rdma.h b/include/linux/nvme-rdma.h
> index 4dd7e6f..c19858b 100644
> --- a/include/linux/nvme-rdma.h
> +++ b/include/linux/nvme-rdma.h
> @@ -8,6 +8,8 @@
>   
>   #define NVME_RDMA_MAX_QUEUE_SIZE	128
>   
> +#define NVME_RDMA_SEND_WR_FACTOR 3  /* MR, SEND, INV */
> +
>   enum nvme_rdma_cm_fmt {
>   	NVME_RDMA_CM_FMT_1_0 = 0x0,
>   };