On 8/9/2017 12:03 PM, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxxxx>
>
> This patch implements the query interface to get all
> ports data for the specific device.
>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> Reviewed-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/infiniband/core/nldev.c | 61 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index 666940f2b49a..4413eda8c435 100644
> --- a/drivers/infiniband/core/nldev.c
> +++ b/drivers/infiniband/core/nldev.c
> @@ -53,6 +53,18 @@ static int fill_dev_info(struct sk_buff *msg, struct ib_device *device)
> return 0;
> }
>
> +static int fill_port_info(struct sk_buff *msg,
> + struct ib_device *device, u32 port)
> +{
> + if (nla_put_u32(msg, RDMA_NLDEV_ATTR_DEV_INDEX, device->index))
> + return -EMSGSIZE;
> + if (nla_put_string(msg, RDMA_NLDEV_ATTR_DEV_NAME, device->name))
> + return -EMSGSIZE;
> + if (nla_put_u32(msg, RDMA_NLDEV_ATTR_PORT_INDEX, port))
> + return -EMSGSIZE;
> + return 0;
> +}
> +
> static int nldev_get_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
> struct netlink_ext_ack *extack)
> {
> @@ -129,11 +141,60 @@ static int nldev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
> return ib_enum_all_devs(_nldev_get_dumpit, skb, cb);
> }
>
> +static int nldev_port_get_dumpit(struct sk_buff *skb,
> + struct netlink_callback *cb)
> +{
> + struct nlattr *tb[RDMA_NLDEV_ATTR_MAX];
> + struct ib_device *device;
> + int start = cb->args[0];
> + struct nlmsghdr *nlh;
> + u32 idx = 0;
> + u32 ifindex;
> + int err;
> + u32 p;
> +
> + err = nlmsg_parse(cb->nlh, 0, tb, RDMA_NLDEV_ATTR_MAX - 1,
> + nldev_policy, NULL);
> + if (err || !tb[RDMA_NLDEV_ATTR_DEV_INDEX])
> + return -EINVAL;
> +
> + ifindex = nla_get_u32(tb[RDMA_NLDEV_ATTR_DEV_INDEX]);
> + device = __ib_device_get_by_index(ifindex);
> + if (!device)
> + return -EINVAL;
> +
> + for (p = rdma_start_port(device); p <= rdma_end_port(device); ++p) {
> + if (idx < start) {
> + idx++;
> + continue;
> + }
So, to someone who has been studying netlink internals (aka, you), the
relationship between cb->args[0] to start to idx to p may make sense.
To those of us that aren't totally versed in what appears to be a
recursive callback, but which isn't clear on how cb->args[0] ever gets
initialized the first time, or how the idx in ib_enum_all_devs()
translates to the idx here, a few comments in the code might be helpful.
> +
> + nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
> + cb->nlh->nlmsg_seq,
> + RDMA_NL_GET_TYPE(RDMA_NL_NLDEV,
> + RDMA_NLDEV_CMD_PORT_GET),
> + 0, NLM_F_MULTI);
> +
> + if (fill_port_info(skb, device, p)) {
> + nlmsg_cancel(skb, nlh);
> + goto out;
> + }
> + idx++;
> + nlmsg_end(skb, nlh);
> + }
> +
> +out: cb->args[0] = idx;
> + return skb->len;
> +}
> +
> static const struct rdma_nl_cbs nldev_cb_table[] = {
> [RDMA_NLDEV_CMD_GET] = {
> .doit = nldev_get_doit,
> .dump = nldev_get_dumpit,
> },
> + [RDMA_NLDEV_CMD_PORT_GET] = {
> + .dump = nldev_port_get_dumpit,
> + },
> };
>
> void __init nldev_init(void)
>
--
Doug Ledford <dledford@xxxxxxxxxx>
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