RDMA/nldev: Provide detailed QP information

Implement RDMA nldev netlink interface to get detailed information on each
QP in the system. This includes the owning process or kernel ULP and
detailed information from the qp_attrs.

Currently only the dumpit variant is implemented.
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/nldev.c

@@ -59,6 +59,18 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_NAME] = { .type = NLA_NUL_STRING,
 					     .len = 16 },
 	[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_CURR] = { .type = NLA_U64 },
+	[RDMA_NLDEV_ATTR_RES_QP]		= { .type = NLA_NESTED },
+	[RDMA_NLDEV_ATTR_RES_QP_ENTRY]		= { .type = NLA_NESTED },
+	[RDMA_NLDEV_ATTR_RES_LQPN]		= { .type = NLA_U32 },
+	[RDMA_NLDEV_ATTR_RES_RQPN]		= { .type = NLA_U32 },
+	[RDMA_NLDEV_ATTR_RES_RQ_PSN]		= { .type = NLA_U32 },
+	[RDMA_NLDEV_ATTR_RES_SQ_PSN]		= { .type = NLA_U32 },
+	[RDMA_NLDEV_ATTR_RES_PATH_MIG_STATE] = { .type = NLA_U8 },
+	[RDMA_NLDEV_ATTR_RES_TYPE]		= { .type = NLA_U8 },
+	[RDMA_NLDEV_ATTR_RES_STATE]		= { .type = NLA_U8 },
+	[RDMA_NLDEV_ATTR_RES_PID]		= { .type = NLA_U32 },
+	[RDMA_NLDEV_ATTR_RES_KERN_NAME]		= { .type = NLA_NUL_STRING,
+						    .len = TASK_COMM_LEN },
 };
 
 static int fill_nldev_handle(struct sk_buff *msg, struct ib_device *device)
@@ -200,6 +212,78 @@ static int fill_res_info(struct sk_buff *msg, struct ib_device *device)
 	return ret;
 }
 
+static int fill_res_qp_entry(struct sk_buff *msg,
+			     struct ib_qp *qp, uint32_t port)
+{
+	struct rdma_restrack_entry *res = &qp->res;
+	struct ib_qp_init_attr qp_init_attr;
+	struct nlattr *entry_attr;
+	struct ib_qp_attr qp_attr;
+	int ret;
+
+	ret = ib_query_qp(qp, &qp_attr, 0, &qp_init_attr);
+	if (ret)
+		return ret;
+
+	if (port && port != qp_attr.port_num)
+		return 0;
+
+	entry_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_RES_QP_ENTRY);
+	if (!entry_attr)
+		goto out;
+
+	/* In create_qp() port is not set yet */
+	if (qp_attr.port_num &&
+	    nla_put_u32(msg, RDMA_NLDEV_ATTR_PORT_INDEX, qp_attr.port_num))
+		goto err;
+
+	if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_LQPN, qp->qp_num))
+		goto err;
+	if (qp->qp_type == IB_QPT_RC || qp->qp_type == IB_QPT_UC) {
+		if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_RQPN,
+				qp_attr.dest_qp_num))
+			goto err;
+		if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_RQ_PSN,
+				qp_attr.rq_psn))
+			goto err;
+	}
+
+	if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_SQ_PSN, qp_attr.sq_psn))
+		goto err;
+
+	if (qp->qp_type == IB_QPT_RC || qp->qp_type == IB_QPT_UC ||
+	    qp->qp_type == IB_QPT_XRC_INI || qp->qp_type == IB_QPT_XRC_TGT) {
+		if (nla_put_u8(msg, RDMA_NLDEV_ATTR_RES_PATH_MIG_STATE,
+			       qp_attr.path_mig_state))
+			goto err;
+	}
+	if (nla_put_u8(msg, RDMA_NLDEV_ATTR_RES_TYPE, qp->qp_type))
+		goto err;
+	if (nla_put_u8(msg, RDMA_NLDEV_ATTR_RES_STATE, qp_attr.qp_state))
+		goto err;
+
+	/*
+	 * Existence of task means that it is user QP and netlink
+	 * user is invited to go and read /proc/PID/comm to get name
+	 * of the task file and res->task_com should be NULL.
+	 */
+	if (rdma_is_kernel_res(res)) {
+		if (nla_put_string(msg, RDMA_NLDEV_ATTR_RES_KERN_NAME, res->kern_name))
+			goto err;
+	} else {
+		if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PID, task_pid_vnr(res->task)))
+			goto err;
+	}
+
+	nla_nest_end(msg, entry_attr);
+	return 0;
+
+err:
+	nla_nest_cancel(msg, entry_attr);
+out:
+	return -EMSGSIZE;
+}
+
 static int nldev_get_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct netlink_ext_ack *extack)
 {
@@ -472,6 +556,136 @@ static int nldev_res_get_dumpit(struct sk_buff *skb,
 	return ib_enum_all_devs(_nldev_res_get_dumpit, skb, cb);
 }
 
+static int nldev_res_get_qp_dumpit(struct sk_buff *skb,
+				   struct netlink_callback *cb)
+{
+	struct nlattr *tb[RDMA_NLDEV_ATTR_MAX];
+	struct rdma_restrack_entry *res;
+	int err, ret = 0, idx = 0;
+	struct nlattr *table_attr;
+	struct ib_device *device;
+	int start = cb->args[0];
+	struct ib_qp *qp = NULL;
+	struct nlmsghdr *nlh;
+	u32 index, port = 0;
+
+	err = nlmsg_parse(cb->nlh, 0, tb, RDMA_NLDEV_ATTR_MAX - 1,
+			  nldev_policy, NULL);
+	/*
+	 * Right now, we are expecting the device index to get QP information,
+	 * but it is possible to extend this code to return all devices in
+	 * one shot by checking the existence of RDMA_NLDEV_ATTR_DEV_INDEX.
+	 * if it doesn't exist, we will iterate over all devices.
+	 *
+	 * But it is not needed for now.
+	 */
+	if (err || !tb[RDMA_NLDEV_ATTR_DEV_INDEX])
+		return -EINVAL;
+
+	index = nla_get_u32(tb[RDMA_NLDEV_ATTR_DEV_INDEX]);
+	device = ib_device_get_by_index(index);
+	if (!device)
+		return -EINVAL;
+
+	/*
+	 * If no PORT_INDEX is supplied, we will return all QPs from that device
+	 */
+	if (tb[RDMA_NLDEV_ATTR_PORT_INDEX]) {
+		port = nla_get_u32(tb[RDMA_NLDEV_ATTR_PORT_INDEX]);
+		if (!rdma_is_port_valid(device, port)) {
+			ret = -EINVAL;
+			goto err_index;
+		}
+	}
+
+	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			RDMA_NL_GET_TYPE(RDMA_NL_NLDEV, RDMA_NLDEV_CMD_RES_QP_GET),
+			0, NLM_F_MULTI);
+
+	if (fill_nldev_handle(skb, device)) {
+		ret = -EMSGSIZE;
+		goto err;
+	}
+
+	table_attr = nla_nest_start(skb, RDMA_NLDEV_ATTR_RES_QP);
+	if (!table_attr) {
+		ret = -EMSGSIZE;
+		goto err;
+	}
+
+	down_read(&device->res.rwsem);
+	hash_for_each_possible(device->res.hash, res, node, RDMA_RESTRACK_QP) {
+		if (idx < start)
+			goto next;
+
+		if ((rdma_is_kernel_res(res) &&
+		     task_active_pid_ns(current) != &init_pid_ns) ||
+		    (!rdma_is_kernel_res(res) &&
+		     task_active_pid_ns(current) != task_active_pid_ns(res->task)))
+			/*
+			 * 1. Kernel QPs should be visible in init namspace only
+			 * 2. Present only QPs visible in the current namespace
+			 */
+			goto next;
+
+		if (!rdma_restrack_get(res))
+			/*
+			 * Resource is under release now, but we are not
+			 * relesing lock now, so it will be released in
+			 * our next pass, once we will get ->next pointer.
+			 */
+			goto next;
+
+		qp = container_of(res, struct ib_qp, res);
+
+		up_read(&device->res.rwsem);
+		ret = fill_res_qp_entry(skb, qp, port);
+		down_read(&device->res.rwsem);
+		/*
+		 * Return resource back, but it won't be released till
+		 * the &device->res.rwsem will be released for write.
+		 */
+		rdma_restrack_put(res);
+
+		if (ret == -EMSGSIZE)
+			/*
+			 * There is a chance to optimize here.
+			 * It can be done by using list_prepare_entry
+			 * and list_for_each_entry_continue afterwards.
+			 */
+			break;
+		if (ret)
+			goto res_err;
+next:		idx++;
+	}
+	up_read(&device->res.rwsem);
+
+	nla_nest_end(skb, table_attr);
+	nlmsg_end(skb, nlh);
+	cb->args[0] = idx;
+
+	/*
+	 * No more QPs to fill, cancel the message and
+	 * return 0 to mark end of dumpit.
+	 */
+	if (!qp)
+		goto err;
+
+	put_device(&device->dev);
+	return skb->len;
+
+res_err:
+	nla_nest_cancel(skb, table_attr);
+	up_read(&device->res.rwsem);
+
+err:
+	nlmsg_cancel(skb, nlh);
+
+err_index:
+	put_device(&device->dev);
+	return ret;
+}
+
 static const struct rdma_nl_cbs nldev_cb_table[RDMA_NLDEV_NUM_OPS] = {
 	[RDMA_NLDEV_CMD_GET] = {
 		.doit = nldev_get_doit,
@@ -485,6 +699,19 @@ static const struct rdma_nl_cbs nldev_cb_table[RDMA_NLDEV_NUM_OPS] = {
 		.doit = nldev_res_get_doit,
 		.dump = nldev_res_get_dumpit,
 	},
+	[RDMA_NLDEV_CMD_RES_QP_GET] = {
+		.dump = nldev_res_get_qp_dumpit,
+		/*
+		 * .doit is not implemented yet for two reasons:
+		 * 1. It is not needed yet.
+		 * 2. There is a need to provide identifier, while it is easy
+		 * for the QPs (device index + port index + LQPN), it is not
+		 * the case for the rest of resources (PD and CQ). Because it
+		 * is better to provide similar interface for all resources,
+		 * let's wait till we will have other resources implemented
+		 * too.
+		 */
+	},
 };
 
 void __init nldev_init(void)

include/uapi/rdma/rdma_netlink.h

@@ -238,6 +238,8 @@ enum rdma_nldev_command {
 
 	RDMA_NLDEV_CMD_RES_GET, /* can dump */
 
+	RDMA_NLDEV_CMD_RES_QP_GET, /* can dump */
+
 	RDMA_NLDEV_NUM_OPS
 };
 
@@ -310,6 +312,46 @@ enum rdma_nldev_attr {
 	RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_NAME,	/* string */
 	RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_CURR,	/* u64 */
 
+	RDMA_NLDEV_ATTR_RES_QP,			/* nested table */
+	RDMA_NLDEV_ATTR_RES_QP_ENTRY,		/* nested table */
+	/*
+	 * Local QPN
+	 */
+	RDMA_NLDEV_ATTR_RES_LQPN,		/* u32 */
+	/*
+	 * Remote QPN,
+	 * Applicable for RC and UC only IBTA 11.2.5.3 QUERY QUEUE PAIR
+	 */
+	RDMA_NLDEV_ATTR_RES_RQPN,		/* u32 */
+	/*
+	 * Receive Queue PSN,
+	 * Applicable for RC and UC only 11.2.5.3 QUERY QUEUE PAIR
+	 */
+	RDMA_NLDEV_ATTR_RES_RQ_PSN,		/* u32 */
+	/*
+	 * Send Queue PSN
+	 */
+	RDMA_NLDEV_ATTR_RES_SQ_PSN,		/* u32 */
+	RDMA_NLDEV_ATTR_RES_PATH_MIG_STATE,	/* u8 */
+	/*
+	 * QP types as visible to RDMA/core, the reserved QPT
+	 * are not exported through this interface.
+	 */
+	RDMA_NLDEV_ATTR_RES_TYPE,		/* u8 */
+	RDMA_NLDEV_ATTR_RES_STATE,		/* u8 */
+	/*
+	 * Process ID which created object,
+	 * in case of kernel origin, PID won't exist.
+	 */
+	RDMA_NLDEV_ATTR_RES_PID,		/* u32 */
+	/*
+	 * The name of process created following resource.
+	 * It will exist only for kernel objects.
+	 * For user created objects, the user is supposed
+	 * to read /proc/PID/comm file.
+	 */
+	RDMA_NLDEV_ATTR_RES_KERN_NAME,		/* string */
+
 	RDMA_NLDEV_ATTR_MAX
 };
 #endif /* _UAPI_RDMA_NETLINK_H */