Remove PID namespaces support from restrack

index 736ab760025d..12ba2685abcf 100644
@@ -149,9 +149,6 @@ static bool auto_mode_match(struct ib_qp *qp, struct rdma_counter *counter,
 	struct auto_mode_param *param = &counter->mode.param;
 	bool match = true;
 
-	if (!rdma_is_visible_in_pid_ns(&qp->res))
-		return false;
-
 	/* Ensure that counter belongs to the right PID */
 	if (task_pid_nr(counter->res.task) != task_pid_nr(qp->res.task))
 		return false;

@@ -229,9 +226,6 @@ static struct rdma_counter *rdma_get_counter_auto_mode(struct ib_qp *qp,
 	rt = &dev->res[RDMA_RESTRACK_COUNTER];
 	xa_lock(&rt->xa);
 	xa_for_each(&rt->xa, id, res) {
-		if (!rdma_is_visible_in_pid_ns(res))
-			continue;
-
 		counter = container_of(res, struct rdma_counter, res);
 		if ((counter->device != qp->device) || (counter->port != port))
 			goto next;

@@ -412,9 +406,6 @@ static struct ib_qp *rdma_counter_get_qp(struct ib_device *dev, u32 qp_num)
 	if (IS_ERR(res))
 		return NULL;
 
-	if (!rdma_is_visible_in_pid_ns(res))
-		goto err;
-
 	qp = container_of(res, struct ib_qp, res);
 	if (qp->qp_type == IB_QPT_RAW_PACKET && !capable(CAP_NET_RAW))
 		goto err;

@@ -445,11 +436,6 @@ static struct rdma_counter *rdma_get_counter_by_id(struct ib_device *dev,
 	if (IS_ERR(res))
 		return NULL;
 
-	if (!rdma_is_visible_in_pid_ns(res)) {
-		rdma_restrack_put(res);
-		return NULL;
-	}
-
 	counter = container_of(res, struct rdma_counter, res);
 	kref_get(&counter->kref);
 	rdma_restrack_put(res);

index 7a7474000100..71bc08510064 100644
@@ -698,9 +698,6 @@ static int fill_stat_counter_qps(struct sk_buff *msg,
 	rt = &counter->device->res[RDMA_RESTRACK_QP];
 	xa_lock(&rt->xa);
 	xa_for_each(&rt->xa, id, res) {
-		if (!rdma_is_visible_in_pid_ns(res))
-			continue;
-
 		qp = container_of(res, struct ib_qp, res);
 		if (qp->qp_type == IB_QPT_RAW_PACKET && !capable(CAP_NET_RAW))
 			continue;

@@ -1222,15 +1219,10 @@ static int res_get_common_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto err;
 	}
 
-	if (!rdma_is_visible_in_pid_ns(res)) {
-		ret = -ENOENT;
-		goto err_get;
-	}
-
 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!msg) {
 		ret = -ENOMEM;
-		goto err;
+		goto err_get;
 	}
 
 	nlh = nlmsg_put(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq,

@@ -1334,9 +1326,6 @@ static int res_get_common_dumpit(struct sk_buff *skb,
 	 * objects.
 	 */
 	xa_for_each(&rt->xa, id, res) {
-		if (!rdma_is_visible_in_pid_ns(res))
-			continue;
-
 		if (idx < start || !rdma_restrack_get(res))
 			goto next;
 

index a07665f7ef8c..62fbb0ae9cb4 100644
@@ -116,11 +116,8 @@ int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type)
 	u32 cnt = 0;
 
 	xa_lock(&rt->xa);
-	xas_for_each(&xas, e, U32_MAX) {
-		if (!rdma_is_visible_in_pid_ns(e))
-			continue;
+	xas_for_each(&xas, e, U32_MAX)
 		cnt++;
-	}
 	xa_unlock(&rt->xa);
 	return cnt;
 }

@@ -346,18 +343,3 @@ void rdma_restrack_del(struct rdma_restrack_entry *res)
 	}
 }
 EXPORT_SYMBOL(rdma_restrack_del);
-
-bool rdma_is_visible_in_pid_ns(struct rdma_restrack_entry *res)
-{
-	/*
-	 * 1. Kern resources should be visible in init
-	 *    namespace only
-	 * 2. Present only resources visible in the current
-	 *     namespace
-	 */
-	if (rdma_is_kernel_res(res))
-		return task_active_pid_ns(current) == &init_pid_ns;
-
-	/* PID 0 means that resource is not found in current namespace */
-	return task_pid_vnr(res->task);
-}

index 7bd177cc0a61..d084e5f89849 100644
@@ -27,5 +27,4 @@ int rdma_restrack_init(struct ib_device *dev);
 void rdma_restrack_clean(struct ib_device *dev);
 void rdma_restrack_attach_task(struct rdma_restrack_entry *res,
 			       struct task_struct *task);
-bool rdma_is_visible_in_pid_ns(struct rdma_restrack_entry *res);
 #endif /* _RDMA_CORE_RESTRACK_H_ */

index 12ba2685abcf..47c551a0bcb0 100644
@@ -149,8 +149,18 @@ static bool auto_mode_match(struct ib_qp *qp, struct rdma_counter *counter,
 	struct auto_mode_param *param = &counter->mode.param;
 	bool match = true;
 
-	/* Ensure that counter belongs to the right PID */
-	if (task_pid_nr(counter->res.task) != task_pid_nr(qp->res.task))
+	/*
+	 * Ensure that counter belongs to the right PID.
+	 * This operation can race with user space which kills
+	 * the process and leaves QP and counters orphans.
+	 *
+	 * It is not a big deal because exitted task will leave both
+	 * QP and counter in the same bucket of zombie process. Just ensure
+	 * that process is still alive before procedding.
+	 *
+	 */
+	if (task_pid_nr(counter->res.task) != task_pid_nr(qp->res.task) ||
+	    !task_pid_nr(qp->res.task))
 		return false;
 
 	if (auto_mask & RDMA_COUNTER_MASK_QP_TYPE)

index 71bc08510064..0ebe95c79ae0 100644
@@ -399,20 +399,34 @@ static int fill_res_info(struct sk_buff *msg, struct ib_device *device)
 static int fill_res_name_pid(struct sk_buff *msg,
 			     struct rdma_restrack_entry *res)
 {
+	int err = 0;
+
 	/*
 	 * For user resources, user is should read /proc/PID/comm to get the
 	 * name of the task file.
 	 */
 	if (rdma_is_kernel_res(res)) {
-		if (nla_put_string(msg, RDMA_NLDEV_ATTR_RES_KERN_NAME,
-		    res->kern_name))
-			return -EMSGSIZE;
+		err = nla_put_string(msg, RDMA_NLDEV_ATTR_RES_KERN_NAME,
+				     res->kern_name);
 	} else {
-		if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PID,
-		    task_pid_vnr(res->task)))
-			return -EMSGSIZE;
+		pid_t pid;
+
+		pid = task_pid_vnr(res->task);
+		/*
+		 * Task is dead and in zombie state.
+		 * There is no need to print PID anymore.
+		 */
+		if (pid)
+			/*
+			 * This part is racy, task can be killed and PID will
+			 * be zero right here but it is ok, next query won't
+			 * return PID. We don't promise real-time reflection
+			 * of SW objects.
+			 */
+			err = nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PID, pid);
 	}
-	return 0;
+
+	return err ? -EMSGSIZE : 0;
 }
 
 static bool fill_res_entry(struct ib_device *dev, struct sk_buff *msg,