1 files changed, 164 insertions, 0 deletions

diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c
new file mode 100644
index 000000000000..857637bf46da
--- /dev/null
+++ b/drivers/infiniband/core/restrack.c
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */
+/*
+ * Copyright (c) 2017-2018 Mellanox Technologies. All rights reserved.
+ */
+
+#include <rdma/ib_verbs.h>
+#include <rdma/restrack.h>
+#include <linux/mutex.h>
+#include <linux/sched/task.h>
+#include <linux/uaccess.h>
+#include <linux/pid_namespace.h>
+
+void rdma_restrack_init(struct rdma_restrack_root *res)
+{
+	init_rwsem(&res->rwsem);
+}
+
+void rdma_restrack_clean(struct rdma_restrack_root *res)
+{
+	WARN_ON_ONCE(!hash_empty(res->hash));
+}
+
+int rdma_restrack_count(struct rdma_restrack_root *res,
+			enum rdma_restrack_type type,
+			struct pid_namespace *ns)
+{
+	struct rdma_restrack_entry *e;
+	u32 cnt = 0;
+
+	down_read(&res->rwsem);
+	hash_for_each_possible(res->hash, e, node, type) {
+		if (ns == &init_pid_ns ||
+		    (!rdma_is_kernel_res(e) &&
+		     ns == task_active_pid_ns(e->task)))
+			cnt++;
+	}
+	up_read(&res->rwsem);
+	return cnt;
+}
+EXPORT_SYMBOL(rdma_restrack_count);
+
+static void set_kern_name(struct rdma_restrack_entry *res)
+{
+	enum rdma_restrack_type type = res->type;
+	struct ib_qp *qp;
+
+	if (type != RDMA_RESTRACK_QP)
+		/* PD and CQ types already have this name embedded in */
+		return;
+
+	qp = container_of(res, struct ib_qp, res);
+	if (!qp->pd) {
+		WARN_ONCE(true, "XRC QPs are not supported\n");
+		/* Survive, despite the programmer's error */
+		res->kern_name = " ";
+		return;
+	}
+
+	res->kern_name = qp->pd->res.kern_name;
+}
+
+static struct ib_device *res_to_dev(struct rdma_restrack_entry *res)
+{
+	enum rdma_restrack_type type = res->type;
+	struct ib_device *dev;
+	struct ib_xrcd *xrcd;
+	struct ib_pd *pd;
+	struct ib_cq *cq;
+	struct ib_qp *qp;
+
+	switch (type) {
+	case RDMA_RESTRACK_PD:
+		pd = container_of(res, struct ib_pd, res);
+		dev = pd->device;
+		break;
+	case RDMA_RESTRACK_CQ:
+		cq = container_of(res, struct ib_cq, res);
+		dev = cq->device;
+		break;
+	case RDMA_RESTRACK_QP:
+		qp = container_of(res, struct ib_qp, res);
+		dev = qp->device;
+		break;
+	case RDMA_RESTRACK_XRCD:
+		xrcd = container_of(res, struct ib_xrcd, res);
+		dev = xrcd->device;
+		break;
+	default:
+		WARN_ONCE(true, "Wrong resource tracking type %u\n", type);
+		return NULL;
+	}
+
+	return dev;
+}
+
+void rdma_restrack_add(struct rdma_restrack_entry *res)
+{
+	struct ib_device *dev = res_to_dev(res);
+
+	if (!dev)
+		return;
+
+	if (!uaccess_kernel()) {
+		get_task_struct(current);
+		res->task = current;
+		res->kern_name = NULL;
+	} else {
+		set_kern_name(res);
+		res->task = NULL;
+	}
+
+	kref_init(&res->kref);
+	init_completion(&res->comp);
+	res->valid = true;
+
+	down_write(&dev->res.rwsem);
+	hash_add(dev->res.hash, &res->node, res->type);
+	up_write(&dev->res.rwsem);
+}
+EXPORT_SYMBOL(rdma_restrack_add);
+
+int __must_check rdma_restrack_get(struct rdma_restrack_entry *res)
+{
+	return kref_get_unless_zero(&res->kref);
+}
+EXPORT_SYMBOL(rdma_restrack_get);
+
+static void restrack_release(struct kref *kref)
+{
+	struct rdma_restrack_entry *res;
+
+	res = container_of(kref, struct rdma_restrack_entry, kref);
+	complete(&res->comp);
+}
+
+int rdma_restrack_put(struct rdma_restrack_entry *res)
+{
+	return kref_put(&res->kref, restrack_release);
+}
+EXPORT_SYMBOL(rdma_restrack_put);
+
+void rdma_restrack_del(struct rdma_restrack_entry *res)
+{
+	struct ib_device *dev;
+
+	if (!res->valid)
+		return;
+
+	dev = res_to_dev(res);
+	if (!dev)
+		return;
+
+	rdma_restrack_put(res);
+
+	wait_for_completion(&res->comp);
+
+	down_write(&dev->res.rwsem);
+	hash_del(&res->node);
+	res->valid = false;
+	if (res->task)
+		put_task_struct(res->task);
+	up_write(&dev->res.rwsem);
+}
+EXPORT_SYMBOL(rdma_restrack_del);