linux/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
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   1/*
   2 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
   3 *
   4 * This software is available to you under a choice of one of two
   5 * licenses.  You may choose to be licensed under the terms of the GNU
   6 * General Public License (GPL) Version 2, available from the file
   7 * COPYING in the main directory of this source tree, or the
   8 * OpenIB.org BSD license below:
   9 *
  10 *     Redistribution and use in source and binary forms, with or
  11 *     without modification, are permitted provided that the following
  12 *     conditions are met:
  13 *
  14 *      - Redistributions of source code must retain the above
  15 *        copyright notice, this list of conditions and the following
  16 *        disclaimer.
  17 *
  18 *      - Redistributions in binary form must reproduce the above
  19 *        copyright notice, this list of conditions and the following
  20 *        disclaimer in the documentation and/or other materials
  21 *        provided with the distribution.
  22 *
  23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30 * SOFTWARE.
  31 */
  32
  33#include <linux/module.h>
  34#include <linux/sched/signal.h>
  35
  36#include <linux/init.h>
  37#include <linux/seq_file.h>
  38
  39#include <linux/uaccess.h>
  40
  41#include "ipoib.h"
  42
  43static ssize_t show_parent(struct device *d, struct device_attribute *attr,
  44                           char *buf)
  45{
  46        struct net_device *dev = to_net_dev(d);
  47        struct ipoib_dev_priv *priv = ipoib_priv(dev);
  48
  49        return sprintf(buf, "%s\n", priv->parent->name);
  50}
  51static DEVICE_ATTR(parent, S_IRUGO, show_parent, NULL);
  52
  53static bool is_child_unique(struct ipoib_dev_priv *ppriv,
  54                            struct ipoib_dev_priv *priv)
  55{
  56        struct ipoib_dev_priv *tpriv;
  57
  58        ASSERT_RTNL();
  59
  60        /*
  61         * Since the legacy sysfs interface uses pkey for deletion it cannot
  62         * support more than one interface with the same pkey, it creates
  63         * ambiguity.  The RTNL interface deletes using the netdev so it does
  64         * not have a problem to support duplicated pkeys.
  65         */
  66        if (priv->child_type != IPOIB_LEGACY_CHILD)
  67                return true;
  68
  69        /*
  70         * First ensure this isn't a duplicate. We check the parent device and
  71         * then all of the legacy child interfaces to make sure the Pkey
  72         * doesn't match.
  73         */
  74        if (ppriv->pkey == priv->pkey)
  75                return false;
  76
  77        list_for_each_entry(tpriv, &ppriv->child_intfs, list) {
  78                if (tpriv->pkey == priv->pkey &&
  79                    tpriv->child_type == IPOIB_LEGACY_CHILD)
  80                        return false;
  81        }
  82
  83        return true;
  84}
  85
  86/*
  87 * NOTE: If this function fails then the priv->dev will remain valid, however
  88 * priv will have been freed and must not be touched by caller in the error
  89 * case.
  90 *
  91 * If (ndev->reg_state == NETREG_UNINITIALIZED) then it is up to the caller to
  92 * free the net_device (just as rtnl_newlink does) otherwise the net_device
  93 * will be freed when the rtnl is unlocked.
  94 */
  95int __ipoib_vlan_add(struct ipoib_dev_priv *ppriv, struct ipoib_dev_priv *priv,
  96                     u16 pkey, int type)
  97{
  98        struct net_device *ndev = priv->dev;
  99        int result;
 100        struct rdma_netdev *rn = netdev_priv(ndev);
 101
 102        ASSERT_RTNL();
 103
 104        /*
 105         * We do not need to touch priv if register_netdevice fails, so just
 106         * always use this flow.
 107         */
 108        ndev->priv_destructor = ipoib_intf_free;
 109
 110        /*
 111         * Racing with unregister of the parent must be prevented by the
 112         * caller.
 113         */
 114        WARN_ON(ppriv->dev->reg_state != NETREG_REGISTERED);
 115
 116        if (pkey == 0 || pkey == 0x8000) {
 117                result = -EINVAL;
 118                goto out_early;
 119        }
 120
 121        rn->mtu = priv->mcast_mtu;
 122
 123        priv->parent = ppriv->dev;
 124        priv->pkey = pkey;
 125        priv->child_type = type;
 126
 127        if (!is_child_unique(ppriv, priv)) {
 128                result = -ENOTUNIQ;
 129                goto out_early;
 130        }
 131
 132        result = register_netdevice(ndev);
 133        if (result) {
 134                ipoib_warn(priv, "failed to initialize; error %i", result);
 135
 136                /*
 137                 * register_netdevice sometimes calls priv_destructor,
 138                 * sometimes not. Make sure it was done.
 139                 */
 140                goto out_early;
 141        }
 142
 143        /* RTNL childs don't need proprietary sysfs entries */
 144        if (type == IPOIB_LEGACY_CHILD) {
 145                if (ipoib_cm_add_mode_attr(ndev))
 146                        goto sysfs_failed;
 147                if (ipoib_add_pkey_attr(ndev))
 148                        goto sysfs_failed;
 149                if (ipoib_add_umcast_attr(ndev))
 150                        goto sysfs_failed;
 151
 152                if (device_create_file(&ndev->dev, &dev_attr_parent))
 153                        goto sysfs_failed;
 154        }
 155
 156        return 0;
 157
 158sysfs_failed:
 159        unregister_netdevice(priv->dev);
 160        return -ENOMEM;
 161
 162out_early:
 163        if (ndev->priv_destructor)
 164                ndev->priv_destructor(ndev);
 165        return result;
 166}
 167
 168int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
 169{
 170        struct ipoib_dev_priv *ppriv, *priv;
 171        char intf_name[IFNAMSIZ];
 172        struct net_device *ndev;
 173        int result;
 174
 175        if (!capable(CAP_NET_ADMIN))
 176                return -EPERM;
 177
 178        if (!rtnl_trylock())
 179                return restart_syscall();
 180
 181        if (pdev->reg_state != NETREG_REGISTERED) {
 182                rtnl_unlock();
 183                return -EPERM;
 184        }
 185
 186        ppriv = ipoib_priv(pdev);
 187
 188        snprintf(intf_name, sizeof(intf_name), "%s.%04x",
 189                 ppriv->dev->name, pkey);
 190
 191        ndev = ipoib_intf_alloc(ppriv->ca, ppriv->port, intf_name);
 192        if (IS_ERR(ndev)) {
 193                result = PTR_ERR(ndev);
 194                goto out;
 195        }
 196        priv = ipoib_priv(ndev);
 197
 198        ndev->rtnl_link_ops = ipoib_get_link_ops();
 199
 200        result = __ipoib_vlan_add(ppriv, priv, pkey, IPOIB_LEGACY_CHILD);
 201
 202        if (result && ndev->reg_state == NETREG_UNINITIALIZED)
 203                free_netdev(ndev);
 204
 205out:
 206        rtnl_unlock();
 207
 208        return result;
 209}
 210
 211struct ipoib_vlan_delete_work {
 212        struct work_struct work;
 213        struct net_device *dev;
 214};
 215
 216/*
 217 * sysfs callbacks of a netdevice cannot obtain the rtnl lock as
 218 * unregister_netdev ultimately deletes the sysfs files while holding the rtnl
 219 * lock. This deadlocks the system.
 220 *
 221 * A callback can use rtnl_trylock to avoid the deadlock but it cannot call
 222 * unregister_netdev as that internally takes and releases the rtnl_lock.  So
 223 * instead we find the netdev to unregister and then do the actual unregister
 224 * from the global work queue where we can obtain the rtnl_lock safely.
 225 */
 226static void ipoib_vlan_delete_task(struct work_struct *work)
 227{
 228        struct ipoib_vlan_delete_work *pwork =
 229                container_of(work, struct ipoib_vlan_delete_work, work);
 230        struct net_device *dev = pwork->dev;
 231
 232        rtnl_lock();
 233
 234        /* Unregistering tasks can race with another task or parent removal */
 235        if (dev->reg_state == NETREG_REGISTERED) {
 236                struct ipoib_dev_priv *priv = ipoib_priv(dev);
 237                struct ipoib_dev_priv *ppriv = ipoib_priv(priv->parent);
 238
 239                ipoib_dbg(ppriv, "delete child vlan %s\n", dev->name);
 240                unregister_netdevice(dev);
 241        }
 242
 243        rtnl_unlock();
 244
 245        kfree(pwork);
 246}
 247
 248int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
 249{
 250        struct ipoib_dev_priv *ppriv, *priv, *tpriv;
 251        int rc;
 252
 253        if (!capable(CAP_NET_ADMIN))
 254                return -EPERM;
 255
 256        if (!rtnl_trylock())
 257                return restart_syscall();
 258
 259        if (pdev->reg_state != NETREG_REGISTERED) {
 260                rtnl_unlock();
 261                return -EPERM;
 262        }
 263
 264        ppriv = ipoib_priv(pdev);
 265
 266        rc = -ENODEV;
 267        list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) {
 268                if (priv->pkey == pkey &&
 269                    priv->child_type == IPOIB_LEGACY_CHILD) {
 270                        struct ipoib_vlan_delete_work *work;
 271
 272                        work = kmalloc(sizeof(*work), GFP_KERNEL);
 273                        if (!work) {
 274                                rc = -ENOMEM;
 275                                goto out;
 276                        }
 277
 278                        down_write(&ppriv->vlan_rwsem);
 279                        list_del_init(&priv->list);
 280                        up_write(&ppriv->vlan_rwsem);
 281                        work->dev = priv->dev;
 282                        INIT_WORK(&work->work, ipoib_vlan_delete_task);
 283                        queue_work(ipoib_workqueue, &work->work);
 284
 285                        rc = 0;
 286                        break;
 287                }
 288        }
 289
 290out:
 291        rtnl_unlock();
 292
 293        return rc;
 294}
 295