Re: [PATCH rdma-next v2 17/17] RDMA/nldev: Allow get default counter statistics through RDMA netlink

[Leon Romanovsky <leon@kernel.org>]

On Wed, May 22, 2019 at 02:30:11PM -0300, Jason Gunthorpe wrote:
> On Mon, Apr 29, 2019 at 11:34:53AM +0300, Leon Romanovsky wrote:
> > From: Mark Zhang <markz@mellanox.com>
> >
> > This patch adds the ability to return the hwstats of per-port default
> > counters (which can also be queried through sysfs nodes).
> >
> > Signed-off-by: Mark Zhang <markz@mellanox.com>
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> >  drivers/infiniband/core/nldev.c | 101 +++++++++++++++++++++++++++++++-
> >  1 file changed, 99 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> > index 53c1d2d82a06..cb2dd38f49f1 100644
> > +++ b/drivers/infiniband/core/nldev.c
> > @@ -1709,6 +1709,98 @@ static int nldev_stat_del_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
> >  	return ret;
> >  }
> >
> > +static int nldev_res_get_default_counter_doit(struct sk_buff *skb,
> > +					      struct nlmsghdr *nlh,
> > +					      struct netlink_ext_ack *extack,
> > +					      struct nlattr *tb[])
> > +{
> > +	struct rdma_hw_stats *stats;
> > +	struct nlattr *table_attr;
> > +	struct ib_device *device;
> > +	int ret, num_cnts, i;
> > +	struct sk_buff *msg;
> > +	u32 index, port;
> > +	u64 v;
> > +
> > +	if (!tb[RDMA_NLDEV_ATTR_DEV_INDEX] || !tb[RDMA_NLDEV_ATTR_PORT_INDEX])
> > +		return -EINVAL;
> > +
> > +	index = nla_get_u32(tb[RDMA_NLDEV_ATTR_DEV_INDEX]);
> > +	device = ib_device_get_by_index(sock_net(skb->sk), index);
> > +	if (!device)
> > +		return -EINVAL;
> > +
> > +	if (!device->ops.alloc_hw_stats || !device->ops.get_hw_stats) {
> > +		ret = -EINVAL;
> > +		goto err;
> > +	}
> > +
> > +	port = nla_get_u32(tb[RDMA_NLDEV_ATTR_PORT_INDEX]);
> > +	if (!rdma_is_port_valid(device, port)) {
> > +		ret = -EINVAL;
> > +		goto err;
> > +	}
> > +
> > +	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
> > +	if (!msg) {
> > +		ret = -ENOMEM;
> > +		goto err;
> > +	}
> > +
> > +	nlh = nlmsg_put(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq,
> > +			RDMA_NL_GET_TYPE(RDMA_NL_NLDEV,
> > +					 RDMA_NLDEV_CMD_STAT_GET),
> > +			0, 0);
> > +
> > +	if (fill_nldev_handle(msg, device) ||
> > +	    nla_put_u32(msg, RDMA_NLDEV_ATTR_PORT_INDEX, port)) {
> > +		ret = -EMSGSIZE;
> > +		goto err_msg;
> > +	}
> > +
> > +	stats = device->ops.alloc_hw_stats(device, port);
> > +	if (!stats) {
> > +		ret = -ENOMEM;
> > +		goto err_msg;
> > +	}
>
> Why do we need yet another one of these to be allocated?

I would say that it is bug.

>
> > +	num_cnts = device->ops.get_hw_stats(device, stats, port, 0);
>
> Is '0' right here?

I think that "index" (third parameter) is not used at all.

>
> Jason