Re: [PATCH net-next v2 12/15] net/smc: Add support for obtaining SMCD device list

[Saeed Mahameed <saeed@kernel.org>]

On Tue, 2020-11-03 at 11:25 +0100, Karsten Graul wrote:
> From: Guvenc Gulce <guvenc@linux.ibm.com>
> 
> Deliver SMCD device information via netlink based
> diagnostic interface.
> 
> Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
> Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
> ---
>  include/uapi/linux/smc.h      |  2 +
>  include/uapi/linux/smc_diag.h | 20 +++++++++
>  net/smc/smc_core.h            | 27 +++++++++++++
>  net/smc/smc_diag.c            | 76
> +++++++++++++++++++++++++++++++++++
>  net/smc/smc_ib.h              |  1 -
>  5 files changed, 125 insertions(+), 1 deletion(-)
> 

> +
> +static int smc_diag_prep_smcd_dev(struct smcd_dev_list *dev_list,
> +				  struct sk_buff *skb,
> +				  struct netlink_callback *cb,
> +				  struct smc_diag_req_v2 *req)
> +{
> +	struct smc_diag_dump_ctx *cb_ctx = smc_dump_context(cb);
> +	int snum = cb_ctx->pos[0];
> +	struct smcd_dev *smcd;
> +	int rc = 0, num = 0;
> +
> +	mutex_lock(&dev_list->mutex);
> +	list_for_each_entry(smcd, &dev_list->list, list) {
> +		if (num < snum)
> +			goto next;
> +		rc = smc_diag_handle_smcd_dev(smcd, skb, cb, req);
> +		if (rc < 0)
> +			goto errout;
> +next:
> +		num++;
> +	}
> +errout:
> +	mutex_unlock(&dev_list->mutex);
> +	cb_ctx->pos[0] = num;
> +	return rc;
> +}
> +

this function pattern repeats at least 4 times in this series and the
only difference is the diag handler function, just abstract this
function out and pass a function pointer as handler to reduce code
repetition.