drivers/infiniband/hw/ipath/ipath_verbs_mcast.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Inc. All rights reserved.
   3  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 #include <linux/list.h>
  35 #include <linux/rcupdate.h>
  36
  37 #include "ipath_verbs.h"
  38
  39 /*
  40  * Global table of GID to attached QPs.
  41  * The table is global to all ipath devices since a send from one QP/device
  42  * needs to be locally routed to any locally attached QPs on the same
  43  * or different device.
  44  */
  45 static struct rb_root mcast_tree;
  46 static DEFINE_SPINLOCK(mcast_lock);
  47
  48 /**
  49  * ipath_mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
  50  * @qp: the QP to link
  51  */
  52 static struct ipath_mcast_qp *ipath_mcast_qp_alloc(struct ipath_qp *qp)
  53 {
  54         struct ipath_mcast_qp *mqp;
  55
  56         mqp = kmalloc(sizeof *mqp, GFP_KERNEL);
  57         if (!mqp)
  58                 goto bail;
  59
  60         mqp->qp = qp;
  61         atomic_inc(&qp->refcount);
  62
  63 bail:
  64         return mqp;
  65 }
  66
  67 static void ipath_mcast_qp_free(struct ipath_mcast_qp *mqp)
  68 {
  69         struct ipath_qp *qp = mqp->qp;
  70
  71         /* Notify ipath_destroy_qp() if it is waiting. */
  72         if (atomic_dec_and_test(&qp->refcount))
  73                 wake_up(&qp->wait);
  74
  75         kfree(mqp);
  76 }
  77
  78 /**
  79  * ipath_mcast_alloc - allocate the multicast GID structure
  80  * @mgid: the multicast GID
  81  *
  82  * A list of QPs will be attached to this structure.
  83  */
  84 static struct ipath_mcast *ipath_mcast_alloc(union ib_gid *mgid)
  85 {
  86         struct ipath_mcast *mcast;
  87
  88         mcast = kmalloc(sizeof *mcast, GFP_KERNEL);
  89         if (!mcast)
  90                 goto bail;
  91
  92         mcast->mgid = *mgid;
  93         INIT_LIST_HEAD(&mcast->qp_list);
  94         init_waitqueue_head(&mcast->wait);
  95         atomic_set(&mcast->refcount, 0);
  96         mcast->n_attached = 0;
  97
  98 bail:
  99         return mcast;
 100 }
 101
 102 static void ipath_mcast_free(struct ipath_mcast *mcast)
 103 {
 104         struct ipath_mcast_qp *p, *tmp;
 105
 106         list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
 107                 ipath_mcast_qp_free(p);
 108
 109         kfree(mcast);
 110 }
 111
 112 /**
 113  * ipath_mcast_find - search the global table for the given multicast GID
 114  * @mgid: the multicast GID to search for
 115  *
 116  * Returns NULL if not found.
 117  *
 118  * The caller is responsible for decrementing the reference count if found.
 119  */
 120 struct ipath_mcast *ipath_mcast_find(union ib_gid *mgid)
 121 {
 122         struct rb_node *n;
 123         unsigned long flags;
 124         struct ipath_mcast *mcast;
 125
 126         spin_lock_irqsave(&mcast_lock, flags);
 127         n = mcast_tree.rb_node;
 128         while (n) {
 129                 int ret;
 130
 131                 mcast = rb_entry(n, struct ipath_mcast, rb_node);
 132
 133                 ret = memcmp(mgid->raw, mcast->mgid.raw,
 134                              sizeof(union ib_gid));
 135                 if (ret < 0)
 136                         n = n->rb_left;
 137                 else if (ret > 0)
 138                         n = n->rb_right;
 139                 else {
 140                         atomic_inc(&mcast->refcount);
 141                         spin_unlock_irqrestore(&mcast_lock, flags);
 142                         goto bail;
 143                 }
 144         }
 145         spin_unlock_irqrestore(&mcast_lock, flags);
 146
 147         mcast = NULL;
 148
 149 bail:
 150         return mcast;
 151 }
 152
 153 /**
 154  * ipath_mcast_add - insert mcast GID into table and attach QP struct
 155  * @mcast: the mcast GID table
 156  * @mqp: the QP to attach
 157  *
 158  * Return zero if both were added.  Return EEXIST if the GID was already in
 159  * the table but the QP was added.  Return ESRCH if the QP was already
 160  * attached and neither structure was added.
 161  */
 162 static int ipath_mcast_add(struct ipath_ibdev *dev,
 163                            struct ipath_mcast *mcast,
 164                            struct ipath_mcast_qp *mqp)
 165 {
 166         struct rb_node **n = &mcast_tree.rb_node;
 167         struct rb_node *pn = NULL;
 168         unsigned long flags;
 169         int ret;
 170
 171         spin_lock_irqsave(&mcast_lock, flags);
 172
 173         while (*n) {
 174                 struct ipath_mcast *tmcast;
 175                 struct ipath_mcast_qp *p;
 176
 177                 pn = *n;
 178                 tmcast = rb_entry(pn, struct ipath_mcast, rb_node);
 179
 180                 ret = memcmp(mcast->mgid.raw, tmcast->mgid.raw,
 181                              sizeof(union ib_gid));
 182                 if (ret < 0) {
 183                         n = &pn->rb_left;
 184                         continue;
 185                 }
 186                 if (ret > 0) {
 187                         n = &pn->rb_right;
 188                         continue;
 189                 }
 190
 191                 /* Search the QP list to see if this is already there. */
 192                 list_for_each_entry_rcu(p, &tmcast->qp_list, list) {
 193                         if (p->qp == mqp->qp) {
 194                                 ret = ESRCH;
 195                                 goto bail;
 196                         }
 197                 }
 198                 if (tmcast->n_attached == ib_ipath_max_mcast_qp_attached) {
 199                         ret = ENOMEM;
 200                         goto bail;
 201                 }
 202
 203                 tmcast->n_attached++;
 204
 205                 list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
 206                 ret = EEXIST;
 207                 goto bail;
 208         }
 209
 210         if (dev->n_mcast_grps_allocated == ib_ipath_max_mcast_grps) {
 211                 ret = ENOMEM;
 212                 goto bail;
 213         }
 214
 215         dev->n_mcast_grps_allocated++;
 216
 217         list_add_tail_rcu(&mqp->list, &mcast->qp_list);
 218
 219         atomic_inc(&mcast->refcount);
 220         rb_link_node(&mcast->rb_node, pn, n);
 221         rb_insert_color(&mcast->rb_node, &mcast_tree);
 222
 223         ret = 0;
 224
 225 bail:
 226         spin_unlock_irqrestore(&mcast_lock, flags);
 227
 228         return ret;
 229 }
 230
 231 int ipath_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 232 {
 233         struct ipath_qp *qp = to_iqp(ibqp);
 234         struct ipath_ibdev *dev = to_idev(ibqp->device);
 235         struct ipath_mcast *mcast;
 236         struct ipath_mcast_qp *mqp;
 237         int ret;
 238
 239         /*
 240          * Allocate data structures since its better to do this outside of
 241          * spin locks and it will most likely be needed.
 242          */
 243         mcast = ipath_mcast_alloc(gid);
 244         if (mcast == NULL) {
 245                 ret = -ENOMEM;
 246                 goto bail;
 247         }
 248         mqp = ipath_mcast_qp_alloc(qp);
 249         if (mqp == NULL) {
 250                 ipath_mcast_free(mcast);
 251                 ret = -ENOMEM;
 252                 goto bail;
 253         }
 254         switch (ipath_mcast_add(dev, mcast, mqp)) {
 255         case ESRCH:
 256                 /* Neither was used: can't attach the same QP twice. */
 257                 ipath_mcast_qp_free(mqp);
 258                 ipath_mcast_free(mcast);
 259                 ret = -EINVAL;
 260                 goto bail;
 261         case EEXIST:            /* The mcast wasn't used */
 262                 ipath_mcast_free(mcast);
 263                 break;
 264         case ENOMEM:
 265                 /* Exceeded the maximum number of mcast groups. */
 266                 ipath_mcast_qp_free(mqp);
 267                 ipath_mcast_free(mcast);
 268                 ret = -ENOMEM;
 269                 goto bail;
 270         default:
 271                 break;
 272         }
 273
 274         ret = 0;
 275
 276 bail:
 277         return ret;
 278 }
 279
 280 int ipath_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 281 {
 282         struct ipath_qp *qp = to_iqp(ibqp);
 283         struct ipath_ibdev *dev = to_idev(ibqp->device);
 284         struct ipath_mcast *mcast = NULL;
 285         struct ipath_mcast_qp *p, *tmp;
 286         struct rb_node *n;
 287         unsigned long flags;
 288         int last = 0;
 289         int ret;
 290
 291         spin_lock_irqsave(&mcast_lock, flags);
 292
 293         /* Find the GID in the mcast table. */
 294         n = mcast_tree.rb_node;
 295         while (1) {
 296                 if (n == NULL) {
 297                         spin_unlock_irqrestore(&mcast_lock, flags);
 298                         ret = -EINVAL;
 299                         goto bail;
 300                 }
 301
 302                 mcast = rb_entry(n, struct ipath_mcast, rb_node);
 303                 ret = memcmp(gid->raw, mcast->mgid.raw,
 304                              sizeof(union ib_gid));
 305                 if (ret < 0)
 306                         n = n->rb_left;
 307                 else if (ret > 0)
 308                         n = n->rb_right;
 309                 else
 310                         break;
 311         }
 312
 313         /* Search the QP list. */
 314         list_for_each_entry_safe(p, tmp, &mcast->qp_list, list) {
 315                 if (p->qp != qp)
 316                         continue;
 317                 /*
 318                  * We found it, so remove it, but don't poison the forward
 319                  * link until we are sure there are no list walkers.
 320                  */
 321                 list_del_rcu(&p->list);
 322                 mcast->n_attached--;
 323
 324                 /* If this was the last attached QP, remove the GID too. */
 325                 if (list_empty(&mcast->qp_list)) {
 326                         rb_erase(&mcast->rb_node, &mcast_tree);
 327                         last = 1;
 328                 }
 329                 break;
 330         }
 331
 332         spin_unlock_irqrestore(&mcast_lock, flags);
 333
 334         if (p) {
 335                 /*
 336                  * Wait for any list walkers to finish before freeing the
 337                  * list element.
 338                  */
 339                 wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
 340                 ipath_mcast_qp_free(p);
 341         }
 342         if (last) {
 343                 atomic_dec(&mcast->refcount);
 344                 wait_event(mcast->wait, !atomic_read(&mcast->refcount));
 345                 ipath_mcast_free(mcast);
 346                 dev->n_mcast_grps_allocated--;
 347         }
 348
 349         ret = 0;
 350
 351 bail:
 352         return ret;
 353 }
 354
 355 int ipath_mcast_tree_empty(void)
 356 {
 357         return mcast_tree.rb_node == NULL;
 358 }