From: hch@lst.de (Christoph Hellwig)
Date: Wed, 6 Sep 2017 12:39:34 +0200
Subject: [PATCH 3/3] nvmet-rdma: add module parameter for SRQ size
In-Reply-To: <1504609157-3004-4-git-send-email-maxg@mellanox.com>
References: <1504609157-3004-1-git-send-email-maxg@mellanox.com>
 <1504609157-3004-4-git-send-email-maxg@mellanox.com>
Message-ID: <20170906103934.GC24667@lst.de>

On Tue, Sep 05, 2017@01:59:17PM +0300, Max Gurtovoy wrote:
> Adjust SRQ size according to the expected load. Make sure the
> size is >= 256 to avoid lack of resources.
> 
> Signed-off-by: Max Gurtovoy <maxg at mellanox.com>
> ---
>  drivers/nvme/target/rdma.c |   23 ++++++++++++++++++++++-
>  1 files changed, 22 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 1b52080..34868ad 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
> @@ -134,6 +134,16 @@ struct nvmet_rdma_device {
>  module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
>  MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
>  
> +static int srq_size_set(const char *val, const struct kernel_param *kp);
> +static const struct kernel_param_ops srq_size_ops = {
> +	.set = srq_size_set,
> +	.get = param_get_int,
> +};
> +
> +static int nvmet_rdma_srq_size = 4095;
> +module_param_cb(srq_size, &srq_size_ops, &nvmet_rdma_srq_size, 0644);
> +MODULE_PARM_DESC(srq_size, "set Shared Receive Queue (SRQ) size, should >= 256 (default: 4095)");
> +
>  static DEFINE_IDA(nvmet_rdma_queue_ida);
>  static LIST_HEAD(nvmet_rdma_queue_list);
>  static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
> @@ -150,6 +160,17 @@ struct nvmet_rdma_device {
>  
>  static struct nvmet_fabrics_ops nvmet_rdma_ops;
>  
> +static int srq_size_set(const char *val, const struct kernel_param *kp)
> +{
> +	int n = 0, ret;
> +
> +	ret = kstrtoint(val, 10, &n);
> +	if (ret != 0 || n < 256)
> +		return -EINVAL;
> +
> +	return param_set_int(val, kp);
> +}

Can you add a new param_set_int_minmax helper to the core module code
instead of having do duplicate this sort of logic in all kinds of drivers?

Otherwise this looks fine to me.