RDMA/rtrs: server: sysfs interface functions

This is the sysfs interface to rtrs sessions on server side:

  /sys/class/rtrs-server/<SESS-NAME>/
    *** rtrs session accepted from a client peer
    |
    |- paths/<SRC@DST>/
       *** established paths from a client in a session
       |
       |- disconnect
       |  *** disconnect path
       |
       |- hca_name
       |  *** HCA name
       |
       |- hca_port
       |  *** HCA port
       |
       |- stats/
          *** current path statistics
          |
	  |- rdma

Link: https://lore.kernel.org/r/20200511135131.27580-13-danil.kipnis@cloud.ionos.comSigned-off-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RDMA Transport Layer
+ *
+ * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
+ * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
+ * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
+ */
+#undef pr_fmt
+#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
+
+#include "rtrs-pri.h"
+#include "rtrs-srv.h"
+#include "rtrs-log.h"
+
+static void rtrs_srv_release(struct kobject *kobj)
+{
+	struct rtrs_srv_sess *sess;
+
+	sess = container_of(kobj, struct rtrs_srv_sess, kobj);
+	kfree(sess);
+}
+
+static struct kobj_type ktype = {
+	.sysfs_ops	= &kobj_sysfs_ops,
+	.release	= rtrs_srv_release,
+};
+
+static ssize_t rtrs_srv_disconnect_show(struct kobject *kobj,
+					 struct kobj_attribute *attr,
+					 char *page)
+{
+	return scnprintf(page, PAGE_SIZE, "Usage: echo 1 > %s\n",
+			 attr->attr.name);
+}
+
+static ssize_t rtrs_srv_disconnect_store(struct kobject *kobj,
+					  struct kobj_attribute *attr,
+					  const char *buf, size_t count)
+{
+	struct rtrs_srv_sess *sess;
+	struct rtrs_sess *s;
+	char str[MAXHOSTNAMELEN];
+
+	sess = container_of(kobj, struct rtrs_srv_sess, kobj);
+	s = &sess->s;
+	if (!sysfs_streq(buf, "1")) {
+		rtrs_err(s, "%s: invalid value: '%s'\n",
+			  attr->attr.name, buf);
+		return -EINVAL;
+	}
+
+	sockaddr_to_str((struct sockaddr *)&sess->s.dst_addr, str, sizeof(str));
+
+	rtrs_info(s, "disconnect for path %s requested\n", str);
+	close_sess(sess);
+
+	return count;
+}
+
+static struct kobj_attribute rtrs_srv_disconnect_attr =
+	__ATTR(disconnect, 0644,
+	       rtrs_srv_disconnect_show, rtrs_srv_disconnect_store);
+
+static ssize_t rtrs_srv_hca_port_show(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       char *page)
+{
+	struct rtrs_srv_sess *sess;
+	struct rtrs_con *usr_con;
+
+	sess = container_of(kobj, typeof(*sess), kobj);
+	usr_con = sess->s.con[0];
+
+	return scnprintf(page, PAGE_SIZE, "%u\n",
+			 usr_con->cm_id->port_num);
+}
+
+static struct kobj_attribute rtrs_srv_hca_port_attr =
+	__ATTR(hca_port, 0444, rtrs_srv_hca_port_show, NULL);
+
+static ssize_t rtrs_srv_hca_name_show(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       char *page)
+{
+	struct rtrs_srv_sess *sess;
+
+	sess = container_of(kobj, struct rtrs_srv_sess, kobj);
+
+	return scnprintf(page, PAGE_SIZE, "%s\n",
+			 sess->s.dev->ib_dev->name);
+}
+
+static struct kobj_attribute rtrs_srv_hca_name_attr =
+	__ATTR(hca_name, 0444, rtrs_srv_hca_name_show, NULL);
+
+static ssize_t rtrs_srv_src_addr_show(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       char *page)
+{
+	struct rtrs_srv_sess *sess;
+	int cnt;
+
+	sess = container_of(kobj, struct rtrs_srv_sess, kobj);
+	cnt = sockaddr_to_str((struct sockaddr *)&sess->s.dst_addr,
+			      page, PAGE_SIZE);
+	return cnt + scnprintf(page + cnt, PAGE_SIZE - cnt, "\n");
+}
+
+static struct kobj_attribute rtrs_srv_src_addr_attr =
+	__ATTR(src_addr, 0444, rtrs_srv_src_addr_show, NULL);
+
+static ssize_t rtrs_srv_dst_addr_show(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       char *page)
+{
+	struct rtrs_srv_sess *sess;
+	int cnt;
+
+	sess = container_of(kobj, struct rtrs_srv_sess, kobj);
+	cnt = sockaddr_to_str((struct sockaddr *)&sess->s.src_addr,
+			      page, PAGE_SIZE);
+	return cnt + scnprintf(page + cnt, PAGE_SIZE - cnt, "\n");
+}
+
+static struct kobj_attribute rtrs_srv_dst_addr_attr =
+	__ATTR(dst_addr, 0444, rtrs_srv_dst_addr_show, NULL);
+
+static struct attribute *rtrs_srv_sess_attrs[] = {
+	&rtrs_srv_hca_name_attr.attr,
+	&rtrs_srv_hca_port_attr.attr,
+	&rtrs_srv_src_addr_attr.attr,
+	&rtrs_srv_dst_addr_attr.attr,
+	&rtrs_srv_disconnect_attr.attr,
+	NULL,
+};
+
+static struct attribute_group rtrs_srv_sess_attr_group = {
+	.attrs = rtrs_srv_sess_attrs,
+};
+
+STAT_ATTR(struct rtrs_srv_stats, rdma,
+	  rtrs_srv_stats_rdma_to_str,
+	  rtrs_srv_reset_rdma_stats);
+
+static struct attribute *rtrs_srv_stats_attrs[] = {
+	&rdma_attr.attr,
+	NULL,
+};
+
+static struct attribute_group rtrs_srv_stats_attr_group = {
+	.attrs = rtrs_srv_stats_attrs,
+};
+
+static void rtrs_srv_dev_release(struct device *dev)
+{
+	struct rtrs_srv *srv = container_of(dev, struct rtrs_srv, dev);
+
+	kfree(srv);
+}
+
+static int rtrs_srv_create_once_sysfs_root_folders(struct rtrs_srv_sess *sess)
+{
+	struct rtrs_srv *srv = sess->srv;
+	int err = 0;
+
+	mutex_lock(&srv->paths_mutex);
+	if (srv->dev_ref++) {
+		/*
+		 * Device needs to be registered only on the first session
+		 */
+		goto unlock;
+	}
+	srv->dev.class = rtrs_dev_class;
+	srv->dev.release = rtrs_srv_dev_release;
+	err = dev_set_name(&srv->dev, "%s", sess->s.sessname);
+	if (err)
+		goto unlock;
+
+	/*
+	 * Suppress user space notification until
+	 * sysfs files are created
+	 */
+	dev_set_uevent_suppress(&srv->dev, true);
+	err = device_register(&srv->dev);
+	if (err) {
+		pr_err("device_register(): %d\n", err);
+		goto put;
+	}
+	srv->kobj_paths = kobject_create_and_add("paths", &srv->dev.kobj);
+	if (!srv->kobj_paths) {
+		pr_err("kobject_create_and_add(): %d\n", err);
+		device_unregister(&srv->dev);
+		goto unlock;
+	}
+	dev_set_uevent_suppress(&srv->dev, false);
+	kobject_uevent(&srv->dev.kobj, KOBJ_ADD);
+	goto unlock;
+
+put:
+	put_device(&srv->dev);
+unlock:
+	mutex_unlock(&srv->paths_mutex);
+
+	return err;
+}
+
+static void
+rtrs_srv_destroy_once_sysfs_root_folders(struct rtrs_srv_sess *sess)
+{
+	struct rtrs_srv *srv = sess->srv;
+
+	mutex_lock(&srv->paths_mutex);
+	if (!--srv->dev_ref) {
+		kobject_del(srv->kobj_paths);
+		kobject_put(srv->kobj_paths);
+		mutex_unlock(&srv->paths_mutex);
+		device_unregister(&srv->dev);
+	} else {
+		mutex_unlock(&srv->paths_mutex);
+	}
+}
+
+static void rtrs_srv_sess_stats_release(struct kobject *kobj)
+{
+	struct rtrs_srv_stats *stats;
+
+	stats = container_of(kobj, struct rtrs_srv_stats, kobj_stats);
+
+	kfree(stats);
+}
+
+static struct kobj_type ktype_stats = {
+	.sysfs_ops = &kobj_sysfs_ops,
+	.release = rtrs_srv_sess_stats_release,
+};
+
+static int rtrs_srv_create_stats_files(struct rtrs_srv_sess *sess)
+{
+	int err;
+	struct rtrs_sess *s = &sess->s;
+
+	err = kobject_init_and_add(&sess->stats->kobj_stats, &ktype_stats,
+				   &sess->kobj, "stats");
+	if (err) {
+		rtrs_err(s, "kobject_init_and_add(): %d\n", err);
+		return err;
+	}
+	err = sysfs_create_group(&sess->stats->kobj_stats,
+				 &rtrs_srv_stats_attr_group);
+	if (err) {
+		rtrs_err(s, "sysfs_create_group(): %d\n", err);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	kobject_del(&sess->stats->kobj_stats);
+	kobject_put(&sess->stats->kobj_stats);
+
+	return err;
+}
+
+int rtrs_srv_create_sess_files(struct rtrs_srv_sess *sess)
+{
+	struct rtrs_srv *srv = sess->srv;
+	struct rtrs_sess *s = &sess->s;
+	char str[NAME_MAX];
+	int err, cnt;
+
+	cnt = sockaddr_to_str((struct sockaddr *)&sess->s.dst_addr,
+			      str, sizeof(str));
+	cnt += scnprintf(str + cnt, sizeof(str) - cnt, "@");
+	sockaddr_to_str((struct sockaddr *)&sess->s.src_addr,
+			str + cnt, sizeof(str) - cnt);
+
+	err = rtrs_srv_create_once_sysfs_root_folders(sess);
+	if (err)
+		return err;
+
+	err = kobject_init_and_add(&sess->kobj, &ktype, srv->kobj_paths,
+				   "%s", str);
+	if (err) {
+		rtrs_err(s, "kobject_init_and_add(): %d\n", err);
+		goto destroy_root;
+	}
+	err = sysfs_create_group(&sess->kobj, &rtrs_srv_sess_attr_group);
+	if (err) {
+		rtrs_err(s, "sysfs_create_group(): %d\n", err);
+		goto put_kobj;
+	}
+	err = rtrs_srv_create_stats_files(sess);
+	if (err)
+		goto remove_group;
+
+	return 0;
+
+remove_group:
+	sysfs_remove_group(&sess->kobj, &rtrs_srv_sess_attr_group);
+put_kobj:
+	kobject_del(&sess->kobj);
+	kobject_put(&sess->kobj);
+destroy_root:
+	rtrs_srv_destroy_once_sysfs_root_folders(sess);
+
+	return err;
+}
+
+void rtrs_srv_destroy_sess_files(struct rtrs_srv_sess *sess)
+{
+	if (sess->kobj.state_in_sysfs) {
+		kobject_del(&sess->stats->kobj_stats);
+		kobject_put(&sess->stats->kobj_stats);
+		kobject_del(&sess->kobj);
+		kobject_put(&sess->kobj);
+
+		rtrs_srv_destroy_once_sysfs_root_folders(sess);
+	}
+}