RDMA/restrack: Introduce statistic counter

Introduce statistic counter as a new resource. It allows a user to monitor
specific objects (e.g., QPs) by binding to a counter.

In some cases a user counter resource is created with task other then
"current", because its creation is done as part of rdmatool call.
Signed-off-by: Mark Zhang <markz@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/restrack.c

@@ -6,6 +6,7 @@
 #include <rdma/rdma_cm.h>
 #include <rdma/ib_verbs.h>
 #include <rdma/restrack.h>
+#include <rdma/rdma_counter.h>
 #include <linux/mutex.h>
 #include <linux/sched/task.h>
 #include <linux/pid_namespace.h>
@@ -45,6 +46,7 @@ static const char *type2str(enum rdma_restrack_type type)
 		[RDMA_RESTRACK_CM_ID] = "CM_ID",
 		[RDMA_RESTRACK_MR] = "MR",
 		[RDMA_RESTRACK_CTX] = "CTX",
+		[RDMA_RESTRACK_COUNTER] = "COUNTER",
 	};
 
 	return names[type];
@@ -169,6 +171,8 @@ static struct ib_device *res_to_dev(struct rdma_restrack_entry *res)
 		return container_of(res, struct ib_mr, res)->device;
 	case RDMA_RESTRACK_CTX:
 		return container_of(res, struct ib_ucontext, res)->device;
+	case RDMA_RESTRACK_COUNTER:
+		return container_of(res, struct rdma_counter, res)->device;
 	default:
 		WARN_ONCE(true, "Wrong resource tracking type %u\n", res->type);
 		return NULL;
@@ -203,15 +207,22 @@ static void rdma_restrack_add(struct rdma_restrack_entry *res)
 
 	kref_init(&res->kref);
 	init_completion(&res->comp);
-	if (res->type != RDMA_RESTRACK_QP)
-		ret = xa_alloc_cyclic(&rt->xa, &res->id, res, xa_limit_32b,
-				&rt->next_id, GFP_KERNEL);
-	else {
+	if (res->type == RDMA_RESTRACK_QP) {
 		/* Special case to ensure that LQPN points to right QP */
 		struct ib_qp *qp = container_of(res, struct ib_qp, res);
 
 		ret = xa_insert(&rt->xa, qp->qp_num, res, GFP_KERNEL);
 		res->id = ret ? 0 : qp->qp_num;
+	} else if (res->type == RDMA_RESTRACK_COUNTER) {
+		/* Special case to ensure that cntn points to right counter */
+		struct rdma_counter *counter;
+
+		counter = container_of(res, struct rdma_counter, res);
+		ret = xa_insert(&rt->xa, counter->id, res, GFP_KERNEL);
+		res->id = ret ? 0 : counter->id;
+	} else {
+		ret = xa_alloc_cyclic(&rt->xa, &res->id, res, xa_limit_32b,
+				      &rt->next_id, GFP_KERNEL);
 	}
 
 	if (!ret)
@@ -237,7 +248,8 @@ EXPORT_SYMBOL(rdma_restrack_kadd);
  */
 void rdma_restrack_uadd(struct rdma_restrack_entry *res)
 {
-	if (res->type != RDMA_RESTRACK_CM_ID)
+	if ((res->type != RDMA_RESTRACK_CM_ID) &&
+	    (res->type != RDMA_RESTRACK_COUNTER))
 		res->task = NULL;
 
 	if (!res->task)

include/rdma/rdma_counter.h

+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2019 Mellanox Technologies. All rights reserved.
+ */
+
+#ifndef _RDMA_COUNTER_H_
+#define _RDMA_COUNTER_H_
+
+#include <rdma/ib_verbs.h>
+#include <rdma/restrack.h>
+
+struct rdma_counter {
+	struct rdma_restrack_entry	res;
+	struct ib_device		*device;
+	uint32_t			id;
+	u8				port;
+};
+#endif /* _RDMA_COUNTER_H_ */

include/rdma/restrack.h

@@ -42,6 +42,10 @@ enum rdma_restrack_type {
 	 * @RDMA_RESTRACK_CTX: Verbs contexts (CTX)
 	 */
 	RDMA_RESTRACK_CTX,
+	/**
+	 * @RDMA_RESTRACK_COUNTER: Statistic Counter
+	 */
+	RDMA_RESTRACK_COUNTER,
 	/**
 	 * @RDMA_RESTRACK_MAX: Last entry, used for array dclarations
 	 */