RDMA/cma: Add support for netlink statistics export

Add callbacks and data types for statistics export of all current
devices/ids.  The schema for RDMA CM is a series of netlink messages.
Each one contains an rdma_cm_stat struct.  Additionally, two netlink
attributes are created for the addresses for each message (if
applicable).

Their types used are:
RDMA_NL_RDMA_CM_ATTR_SRC_ADDR (The source address for this ID)
RDMA_NL_RDMA_CM_ATTR_DST_ADDR (The destination address for this ID)
sockaddr_* structs are encapsulated within these attributes.

In other words, every transaction contains a series of messages like:

-------message 1-------
struct rdma_cm_id_stats {
       __u32 qp_num;
       __u32 bound_dev_if;
       __u32 port_space;
       __s32 pid;
       __u8 cm_state;
       __u8 node_type;
       __u8 port_num;
       __u8 reserved;
}
RDMA_NL_RDMA_CM_ATTR_SRC_ADDR attribute - contains the source address
RDMA_NL_RDMA_CM_ATTR_DST_ADDR attribute - contains the destination address
-------end 1-------
-------message 2-------
struct rdma_cm_id_stats
RDMA_NL_RDMA_CM_ATTR_SRC_ADDR attribute
RDMA_NL_RDMA_CM_ATTR_DST_ADDR attribute
-------end 2-------

Signed-off-by: Nir Muchtar <nirm@voltaire.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 127 insertions, 0 deletions

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 44be1c9ed05b..5dd9acb92c3a 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -47,6 +47,7 @@
 
 #include <rdma/rdma_cm.h>
 #include <rdma/rdma_cm_ib.h>
+#include <rdma/rdma_netlink.h>
 #include <rdma/ib_cache.h>
 #include <rdma/ib_cm.h>
 #include <rdma/ib_sa.h>
@@ -3315,6 +3316,99 @@ static void cma_remove_one(struct ib_device *device)
         kfree(cma_dev);
 }
 
+static int cma_get_id_stats(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        struct nlmsghdr *nlh;
+        struct rdma_cm_id_stats *id_stats;
+        struct rdma_id_private *id_priv;
+        struct rdma_cm_id *id = NULL;
+        struct cma_device *cma_dev;
+        int i_dev = 0, i_id = 0;
+
+        /*
+         * We export all of the IDs as a sequence of messages.  Each
+         * ID gets its own netlink message.
+         */
+        mutex_lock(&lock);
+
+        list_for_each_entry(cma_dev, &dev_list, list) {
+                if (i_dev < cb->args[0]) {
+                        i_dev++;
+                        continue;
+                }
+
+                i_id = 0;
+                list_for_each_entry(id_priv, &cma_dev->id_list, list) {
+                        if (i_id < cb->args[1]) {
+                                i_id++;
+                                continue;
+                        }
+
+                        id_stats = ibnl_put_msg(skb, &nlh, cb->nlh->nlmsg_seq,
+                                                sizeof *id_stats, RDMA_NL_RDMA_CM,
+                                                RDMA_NL_RDMA_CM_ID_STATS);
+                        if (!id_stats)
+                                goto out;
+
+                        memset(id_stats, 0, sizeof *id_stats);
+                        id = &id_priv->id;
+                        id_stats->node_type = id->route.addr.dev_addr.dev_type;
+                        id_stats->port_num = id->port_num;
+                        id_stats->bound_dev_if =
+                                id->route.addr.dev_addr.bound_dev_if;
+
+                        if (id->route.addr.src_addr.ss_family == AF_INET) {
+                                if (ibnl_put_attr(skb, nlh,
+                                                  sizeof(struct sockaddr_in),
+                                                  &id->route.addr.src_addr,
+                                                  RDMA_NL_RDMA_CM_ATTR_SRC_ADDR)) {
+                                        goto out;
+                                }
+                                if (ibnl_put_attr(skb, nlh,
+                                                  sizeof(struct sockaddr_in),
+                                                  &id->route.addr.dst_addr,
+                                                  RDMA_NL_RDMA_CM_ATTR_DST_ADDR)) {
+                                        goto out;
+                                }
+                        } else if (id->route.addr.src_addr.ss_family == AF_INET6) {
+                                if (ibnl_put_attr(skb, nlh,
+                                                  sizeof(struct sockaddr_in6),
+                                                  &id->route.addr.src_addr,
+                                                  RDMA_NL_RDMA_CM_ATTR_SRC_ADDR)) {
+                                        goto out;
+                                }
+                                if (ibnl_put_attr(skb, nlh,
+                                                  sizeof(struct sockaddr_in6),
+                                                  &id->route.addr.dst_addr,
+                                                  RDMA_NL_RDMA_CM_ATTR_DST_ADDR)) {
+                                        goto out;
+                                }
+                        }
+
+                        id_stats->port_space    = id->ps;
+                        id_stats->cm_state      = id_priv->state;
+                        id_stats->qp_num        = id_priv->qp_num;
+                        id_stats->qp_type       = id->qp_type;
+
+                        i_id++;
+                }
+
+                cb->args[1] = 0;
+                i_dev++;
+        }
+
+out:
+        mutex_unlock(&lock);
+        cb->args[0] = i_dev;
+        cb->args[1] = i_id;
+
+        return skb->len;
+}
+
+static const struct ibnl_client_cbs cma_cb_table[] = {
+        [RDMA_NL_RDMA_CM_ID_STATS] = { .dump = cma_get_id_stats },
+};
+
 static int __init cma_init(void)
 {
         int ret;
@@ -3330,6 +3424,10 @@ static int __init cma_init(void)
         ret = ib_register_client(&cma_client);
         if (ret)
                 goto err;
+
+        if (ibnl_add_client(RDMA_NL_RDMA_CM, RDMA_NL_RDMA_CM_NUM_OPS, cma_cb_table))
+                printk(KERN_WARNING "RDMA CMA: failed to add netlink callback\n");
+
         return 0;
 
 err:
@@ -3342,6 +3440,7 @@ err:
 
 static void __exit cma_cleanup(void)
 {
+        ibnl_remove_client(RDMA_NL_RDMA_CM);
         ib_unregister_client(&cma_client);
         unregister_netdevice_notifier(&cma_nb);
         rdma_addr_unregister_client(&addr_client);
diff --git a/include/rdma/rdma_netlink.h b/include/rdma/rdma_netlink.h
index c983a193cecf..3c5363ab867b 100644
--- a/include/rdma/rdma_netlink.h
+++ b/include/rdma/rdma_netlink.h
@@ -1,10 +1,38 @@
 #ifndef _RDMA_NETLINK_H
 #define _RDMA_NETLINK_H
 
+#include <linux/types.h>
+
+enum {
+        RDMA_NL_RDMA_CM = 1
+};
+
 #define RDMA_NL_GET_CLIENT(type) ((type & (((1 << 6) - 1) << 10)) >> 10)
 #define RDMA_NL_GET_OP(type) (type & ((1 << 10) - 1))
 #define RDMA_NL_GET_TYPE(client, op) ((client << 10) + op)
 
+enum {
+        RDMA_NL_RDMA_CM_ID_STATS = 0,
+        RDMA_NL_RDMA_CM_NUM_OPS
+};
+
+enum {
+        RDMA_NL_RDMA_CM_ATTR_SRC_ADDR = 1,
+        RDMA_NL_RDMA_CM_ATTR_DST_ADDR,
+        RDMA_NL_RDMA_CM_NUM_ATTR,
+};
+
+struct rdma_cm_id_stats {
+        __u32   qp_num;
+        __u32   bound_dev_if;
+        __u32   port_space;
+        __s32   pid;
+        __u8    cm_state;
+        __u8    node_type;
+        __u8    port_num;
+        __u8    qp_type;
+};
+
 #ifdef __KERNEL__
 
 #include <linux/netlink.h>