drivers/staging/rdma/hfi1/verbs_mcast.c

   1 /*
   2  *
   3  * This file is provided under a dual BSD/GPLv2 license.  When using or
   4  * redistributing this file, you may do so under either license.
   5  *
   6  * GPL LICENSE SUMMARY
   7  *
   8  * Copyright(c) 2015 Intel Corporation.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of version 2 of the GNU General Public License as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * BSD LICENSE
  20  *
  21  * Copyright(c) 2015 Intel Corporation.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  *
  27  *  - Redistributions of source code must retain the above copyright
  28  *    notice, this list of conditions and the following disclaimer.
  29  *  - Redistributions in binary form must reproduce the above copyright
  30  *    notice, this list of conditions and the following disclaimer in
  31  *    the documentation and/or other materials provided with the
  32  *    distribution.
  33  *  - Neither the name of Intel Corporation nor the names of its
  34  *    contributors may be used to endorse or promote products derived
  35  *    from this software without specific prior written permission.
  36  *
  37  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  38  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  39  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  40  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  41  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  44  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  45  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  46  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  47  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  48  *
  49  */
  50
  51 #include <linux/rculist.h>
  52
  53 #include "hfi.h"
  54
  55 /**
  56  * mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
  57  * @qp: the QP to link
  58  */
  59 static struct hfi1_mcast_qp *mcast_qp_alloc(struct hfi1_qp *qp)
  60 {
  61         struct hfi1_mcast_qp *mqp;
  62
  63         mqp = kmalloc(sizeof(*mqp), GFP_KERNEL);
  64         if (!mqp)
  65                 goto bail;
  66
  67         mqp->qp = qp;
  68         atomic_inc(&qp->refcount);
  69
  70 bail:
  71         return mqp;
  72 }
  73
  74 static void mcast_qp_free(struct hfi1_mcast_qp *mqp)
  75 {
  76         struct hfi1_qp *qp = mqp->qp;
  77
  78         /* Notify hfi1_destroy_qp() if it is waiting. */
  79         if (atomic_dec_and_test(&qp->refcount))
  80                 wake_up(&qp->wait);
  81
  82         kfree(mqp);
  83 }
  84
  85 /**
  86  * mcast_alloc - allocate the multicast GID structure
  87  * @mgid: the multicast GID
  88  *
  89  * A list of QPs will be attached to this structure.
  90  */
  91 static struct hfi1_mcast *mcast_alloc(union ib_gid *mgid)
  92 {
  93         struct hfi1_mcast *mcast;
  94
  95         mcast = kmalloc(sizeof(*mcast), GFP_KERNEL);
  96         if (!mcast)
  97                 goto bail;
  98
  99         mcast->mgid = *mgid;
 100         INIT_LIST_HEAD(&mcast->qp_list);
 101         init_waitqueue_head(&mcast->wait);
 102         atomic_set(&mcast->refcount, 0);
 103         mcast->n_attached = 0;
 104
 105 bail:
 106         return mcast;
 107 }
 108
 109 static void mcast_free(struct hfi1_mcast *mcast)
 110 {
 111         struct hfi1_mcast_qp *p, *tmp;
 112
 113         list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
 114                 mcast_qp_free(p);
 115
 116         kfree(mcast);
 117 }
 118
 119 /**
 120  * hfi1_mcast_find - search the global table for the given multicast GID
 121  * @ibp: the IB port structure
 122  * @mgid: the multicast GID to search for
 123  *
 124  * Returns NULL if not found.
 125  *
 126  * The caller is responsible for decrementing the reference count if found.
 127  */
 128 struct hfi1_mcast *hfi1_mcast_find(struct hfi1_ibport *ibp, union ib_gid *mgid)
 129 {
 130         struct rb_node *n;
 131         unsigned long flags;
 132         struct hfi1_mcast *mcast;
 133
 134         spin_lock_irqsave(&ibp->lock, flags);
 135         n = ibp->mcast_tree.rb_node;
 136         while (n) {
 137                 int ret;
 138
 139                 mcast = rb_entry(n, struct hfi1_mcast, rb_node);
 140
 141                 ret = memcmp(mgid->raw, mcast->mgid.raw,
 142                              sizeof(union ib_gid));
 143                 if (ret < 0)
 144                         n = n->rb_left;
 145                 else if (ret > 0)
 146                         n = n->rb_right;
 147                 else {
 148                         atomic_inc(&mcast->refcount);
 149                         spin_unlock_irqrestore(&ibp->lock, flags);
 150                         goto bail;
 151                 }
 152         }
 153         spin_unlock_irqrestore(&ibp->lock, flags);
 154
 155         mcast = NULL;
 156
 157 bail:
 158         return mcast;
 159 }
 160
 161 /**
 162  * mcast_add - insert mcast GID into table and attach QP struct
 163  * @mcast: the mcast GID table
 164  * @mqp: the QP to attach
 165  *
 166  * Return zero if both were added.  Return EEXIST if the GID was already in
 167  * the table but the QP was added.  Return ESRCH if the QP was already
 168  * attached and neither structure was added.
 169  */
 170 static int mcast_add(struct hfi1_ibdev *dev, struct hfi1_ibport *ibp,
 171                      struct hfi1_mcast *mcast, struct hfi1_mcast_qp *mqp)
 172 {
 173         struct rb_node **n = &ibp->mcast_tree.rb_node;
 174         struct rb_node *pn = NULL;
 175         int ret;
 176
 177         spin_lock_irq(&ibp->lock);
 178
 179         while (*n) {
 180                 struct hfi1_mcast *tmcast;
 181                 struct hfi1_mcast_qp *p;
 182
 183                 pn = *n;
 184                 tmcast = rb_entry(pn, struct hfi1_mcast, rb_node);
 185
 186                 ret = memcmp(mcast->mgid.raw, tmcast->mgid.raw,
 187                              sizeof(union ib_gid));
 188                 if (ret < 0) {
 189                         n = &pn->rb_left;
 190                         continue;
 191                 }
 192                 if (ret > 0) {
 193                         n = &pn->rb_right;
 194                         continue;
 195                 }
 196
 197                 /* Search the QP list to see if this is already there. */
 198                 list_for_each_entry_rcu(p, &tmcast->qp_list, list) {
 199                         if (p->qp == mqp->qp) {
 200                                 ret = ESRCH;
 201                                 goto bail;
 202                         }
 203                 }
 204                 if (tmcast->n_attached == hfi1_max_mcast_qp_attached) {
 205                         ret = ENOMEM;
 206                         goto bail;
 207                 }
 208
 209                 tmcast->n_attached++;
 210
 211                 list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
 212                 ret = EEXIST;
 213                 goto bail;
 214         }
 215
 216         spin_lock(&dev->n_mcast_grps_lock);
 217         if (dev->n_mcast_grps_allocated == hfi1_max_mcast_grps) {
 218                 spin_unlock(&dev->n_mcast_grps_lock);
 219                 ret = ENOMEM;
 220                 goto bail;
 221         }
 222
 223         dev->n_mcast_grps_allocated++;
 224         spin_unlock(&dev->n_mcast_grps_lock);
 225
 226         mcast->n_attached++;
 227
 228         list_add_tail_rcu(&mqp->list, &mcast->qp_list);
 229
 230         atomic_inc(&mcast->refcount);
 231         rb_link_node(&mcast->rb_node, pn, n);
 232         rb_insert_color(&mcast->rb_node, &ibp->mcast_tree);
 233
 234         ret = 0;
 235
 236 bail:
 237         spin_unlock_irq(&ibp->lock);
 238
 239         return ret;
 240 }
 241
 242 int hfi1_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 243 {
 244         struct hfi1_qp *qp = to_iqp(ibqp);
 245         struct hfi1_ibdev *dev = to_idev(ibqp->device);
 246         struct hfi1_ibport *ibp;
 247         struct hfi1_mcast *mcast;
 248         struct hfi1_mcast_qp *mqp;
 249         int ret;
 250
 251         if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET) {
 252                 ret = -EINVAL;
 253                 goto bail;
 254         }
 255
 256         /*
 257          * Allocate data structures since its better to do this outside of
 258          * spin locks and it will most likely be needed.
 259          */
 260         mcast = mcast_alloc(gid);
 261         if (mcast == NULL) {
 262                 ret = -ENOMEM;
 263                 goto bail;
 264         }
 265         mqp = mcast_qp_alloc(qp);
 266         if (mqp == NULL) {
 267                 mcast_free(mcast);
 268                 ret = -ENOMEM;
 269                 goto bail;
 270         }
 271         ibp = to_iport(ibqp->device, qp->port_num);
 272         switch (mcast_add(dev, ibp, mcast, mqp)) {
 273         case ESRCH:
 274                 /* Neither was used: OK to attach the same QP twice. */
 275                 mcast_qp_free(mqp);
 276                 mcast_free(mcast);
 277                 break;
 278
 279         case EEXIST:            /* The mcast wasn't used */
 280                 mcast_free(mcast);
 281                 break;
 282
 283         case ENOMEM:
 284                 /* Exceeded the maximum number of mcast groups. */
 285                 mcast_qp_free(mqp);
 286                 mcast_free(mcast);
 287                 ret = -ENOMEM;
 288                 goto bail;
 289
 290         default:
 291                 break;
 292         }
 293
 294         ret = 0;
 295
 296 bail:
 297         return ret;
 298 }
 299
 300 int hfi1_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 301 {
 302         struct hfi1_qp *qp = to_iqp(ibqp);
 303         struct hfi1_ibdev *dev = to_idev(ibqp->device);
 304         struct hfi1_ibport *ibp = to_iport(ibqp->device, qp->port_num);
 305         struct hfi1_mcast *mcast = NULL;
 306         struct hfi1_mcast_qp *p, *tmp;
 307         struct rb_node *n;
 308         int last = 0;
 309         int ret;
 310
 311         if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET) {
 312                 ret = -EINVAL;
 313                 goto bail;
 314         }
 315
 316         spin_lock_irq(&ibp->lock);
 317
 318         /* Find the GID in the mcast table. */
 319         n = ibp->mcast_tree.rb_node;
 320         while (1) {
 321                 if (n == NULL) {
 322                         spin_unlock_irq(&ibp->lock);
 323                         ret = -EINVAL;
 324                         goto bail;
 325                 }
 326
 327                 mcast = rb_entry(n, struct hfi1_mcast, rb_node);
 328                 ret = memcmp(gid->raw, mcast->mgid.raw,
 329                              sizeof(union ib_gid));
 330                 if (ret < 0)
 331                         n = n->rb_left;
 332                 else if (ret > 0)
 333                         n = n->rb_right;
 334                 else
 335                         break;
 336         }
 337
 338         /* Search the QP list. */
 339         list_for_each_entry_safe(p, tmp, &mcast->qp_list, list) {
 340                 if (p->qp != qp)
 341                         continue;
 342                 /*
 343                  * We found it, so remove it, but don't poison the forward
 344                  * link until we are sure there are no list walkers.
 345                  */
 346                 list_del_rcu(&p->list);
 347                 mcast->n_attached--;
 348
 349                 /* If this was the last attached QP, remove the GID too. */
 350                 if (list_empty(&mcast->qp_list)) {
 351                         rb_erase(&mcast->rb_node, &ibp->mcast_tree);
 352                         last = 1;
 353                 }
 354                 break;
 355         }
 356
 357         spin_unlock_irq(&ibp->lock);
 358
 359         if (p) {
 360                 /*
 361                  * Wait for any list walkers to finish before freeing the
 362                  * list element.
 363                  */
 364                 wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
 365                 mcast_qp_free(p);
 366         }
 367         if (last) {
 368                 atomic_dec(&mcast->refcount);
 369                 wait_event(mcast->wait, !atomic_read(&mcast->refcount));
 370                 mcast_free(mcast);
 371                 spin_lock_irq(&dev->n_mcast_grps_lock);
 372                 dev->n_mcast_grps_allocated--;
 373                 spin_unlock_irq(&dev->n_mcast_grps_lock);
 374         }
 375
 376         ret = 0;
 377
 378 bail:
 379         return ret;
 380 }
 381
 382 int hfi1_mcast_tree_empty(struct hfi1_ibport *ibp)
 383 {
 384         return ibp->mcast_tree.rb_node == NULL;
 385 }