RDMA/core: Change system parameters callback from dumpit to doit

.dumpit() callback is used for returning same type of data in the loop,
e.g. loop over ports, resources, devices.

However system parameters are general and standalone for whole
subsystem. It means that getting system parameters should be doit
callback.

Fixes: cb7e0e1 ("RDMA/core: Add interface to read device namespace sharing mode")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/nldev.c

@@ -1346,32 +1346,35 @@ static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	return 0;
 }
 
-static int nldev_get_sys_get_dumpit(struct sk_buff *skb,
-				    struct netlink_callback *cb)
+static int nldev_sys_get_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
+			      struct netlink_ext_ack *extack)
 {
 	struct nlattr *tb[RDMA_NLDEV_ATTR_MAX];
-	struct nlmsghdr *nlh;
+	struct sk_buff *msg;
 	int err;
 
-	err = nlmsg_parse(cb->nlh, 0, tb, RDMA_NLDEV_ATTR_MAX - 1,
-			  nldev_policy, NULL);
+	err = nlmsg_parse(nlh, 0, tb, RDMA_NLDEV_ATTR_MAX - 1,
+			  nldev_policy, extack);
 	if (err)
 		return err;
 
-	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	nlh = nlmsg_put(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq,
 			RDMA_NL_GET_TYPE(RDMA_NL_NLDEV,
 					 RDMA_NLDEV_CMD_SYS_GET),
 			0, 0);
 
-	err = nla_put_u8(skb, RDMA_NLDEV_SYS_ATTR_NETNS_MODE,
+	err = nla_put_u8(msg, RDMA_NLDEV_SYS_ATTR_NETNS_MODE,
 			 (u8)ib_devices_shared_netns);
 	if (err) {
-		nlmsg_cancel(skb, nlh);
+		nlmsg_free(msg);
 		return err;
 	}
-
-	nlmsg_end(skb, nlh);
-	return skb->len;
+	nlmsg_end(msg, nlh);
+	return rdma_nl_unicast(msg, NETLINK_CB(skb).portid);
 }
 
 static int nldev_set_sys_set_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -1441,7 +1444,7 @@ static const struct rdma_nl_cbs nldev_cb_table[RDMA_NLDEV_NUM_OPS] = {
 		.dump = nldev_res_get_pd_dumpit,
 	},
 	[RDMA_NLDEV_CMD_SYS_GET] = {
-		.dump = nldev_get_sys_get_dumpit,
+		.doit = nldev_sys_get_doit,
 	},
 	[RDMA_NLDEV_CMD_SYS_SET] = {
 		.doit = nldev_set_sys_set_doit,

include/uapi/rdma/rdma_netlink.h

@@ -250,7 +250,7 @@ enum rdma_nldev_command {
 
 	RDMA_NLDEV_CMD_PORT_GET, /* can dump */
 
-	RDMA_NLDEV_CMD_SYS_GET, /* can dump */
+	RDMA_NLDEV_CMD_SYS_GET,
 	RDMA_NLDEV_CMD_SYS_SET,
 
 	/* 8 is free to use */