On Thu, Sep 13, 2018 at 12:16:20PM -0700, Steve Wise wrote:
> Add support for new LINK messages to allow adding and deleting rdma
> interfaces. This will be used initially for soft rdma drivers which
> instantiate device instances dynamically by the admin specifying a netdev
> device to use. The rdma_rxe module will be the first user of these
> messages.
>
> The design is modeled after RTNL_NEWLINK/DELLINK: rdma drivers
> register with the rdma core if they provide link add/delete functions.
> Each driver registers with a unique "type" string, that is used to
> dispatch messages coming from user space. A new RDMA_NLDEV_ATTR is
> defined for the "type" string. User mode will pass 3 attributes in a
> NEWLINK message: RDMA_NLDEV_ATTR_IBDEV_NAME for the desired rdma device
> name to be created, RDMA_NLDEV_ATTR_LINK_TYPE for the "type" of link
> being added, and RDMA_NLDEV_ATTR_NDEV_NAME for the net_device interface
> to use for this link. The DELLINK message will contain the IBDEV_NAME
> and LINK_TYPE attributes.
>
> Signed-off-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
> drivers/infiniband/core/nldev.c | 113 +++++++++++++++++++++++++++++++++++++++
> include/rdma/rdma_netlink.h | 11 ++++
> include/uapi/rdma/rdma_netlink.h | 9 ++++
> 3 files changed, 133 insertions(+)
>
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index 0385ab438320..d107b982c210 100644
> +++ b/drivers/infiniband/core/nldev.c
> @@ -33,6 +33,7 @@
> #include <linux/module.h>
> #include <linux/pid.h>
> #include <linux/pid_namespace.h>
> +#include <linux/mutex.h>
> #include <net/netlink.h>
> #include <rdma/rdma_cm.h>
> #include <rdma/rdma_netlink.h>
> @@ -107,6 +108,8 @@
> [RDMA_NLDEV_ATTR_DRIVER_U32] = { .type = NLA_U32 },
> [RDMA_NLDEV_ATTR_DRIVER_S64] = { .type = NLA_S64 },
> [RDMA_NLDEV_ATTR_DRIVER_U64] = { .type = NLA_U64 },
> + [RDMA_NLDEV_ATTR_LINK_TYPE] = { .type = NLA_NUL_STRING,
> + .len = IFNAMSIZ },
> };
>
> static int put_driver_name_print_type(struct sk_buff *msg, const char *name,
> @@ -1072,6 +1075,110 @@ static int nldev_res_get_pd_dumpit(struct sk_buff *skb,
> return res_get_common_dumpit(skb, cb, RDMA_RESTRACK_PD);
> }
>
> +static LIST_HEAD(link_ops);
> +static DEFINE_MUTEX(link_ops_mutex);
> +
> +void rdma_link_register(struct rdma_link_ops *ops)
> +{
> + mutex_lock(&link_ops_mutex);
> + list_add(&ops->list, &link_ops);
Make sure the name is unique
> + mutex_unlock(&link_ops_mutex);
> +}
> +EXPORT_SYMBOL(rdma_link_register);
> +
> +void rdma_link_unregister(struct rdma_link_ops *ops)
> +{
> + mutex_lock(&link_ops_mutex);
> + list_del_init(&ops->list);
> + mutex_unlock(&link_ops_mutex);
> +}
> +EXPORT_SYMBOL(rdma_link_unregister);
> +
> +static const struct rdma_link_ops *link_ops_get(const char *type)
> +{
> + const struct rdma_link_ops *ops;
> +
> + mutex_lock(&link_ops_mutex);
> + list_for_each_entry(ops, &link_ops, list) {
> + if (!strncmp(ops->type, type, IFNAMSIZ))
Why strncmp here? Both strings should be null terminated.
> + goto out;
> + }
> + ops = NULL;
This should trigger module automatic loading and try again.
Ie call
request_module("rdma-link-%s", type);
And rxe should provide that symbol as a module-alias.
See the similar code in netdev, ie MODULE_ALIAS_RTNL_LINK and the
request_module calls
Jason
