drivers/infiniband/hw/ipath/ipath_verbs_mcast.c

   1 /*
   2  * Copyright (c) 2006, 2007 QLogic Corporation. 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/rculist.h>
  35 #include <linux/sched.h>
  36 #include <linux/slab.h>
  37
  38 #include "ipath_verbs.h"
  39
  40 /*
  41  * Global table of GID to attached QPs.
  42  * The table is global to all ipath devices since a send from one QP/device
  43  * needs to be locally routed to any locally attached QPs on the same
  44  * or different device.
  45  */
  46 static struct rb_root mcast_tree;
  47 static DEFINE_SPINLOCK(mcast_lock);
  48
  49 /**
  50  * ipath_mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
  51  * @qp: the QP to link
  52  */
  53 static struct ipath_mcast_qp *ipath_mcast_qp_alloc(struct ipath_qp *qp)
  54 {
  55         struct ipath_mcast_qp *mqp;
  56
  57         mqp = kmalloc(sizeof *mqp, GFP_KERNEL);
  58         if (!mqp)
  59                 goto bail;
  60
  61         mqp->qp = qp;
  62         atomic_inc(&qp->refcount);
  63
  64 bail:
  65         return mqp;
  66 }
  67
  68 static void ipath_mcast_qp_free(struct ipath_mcast_qp *mqp)
  69 {
  70         struct ipath_qp *qp = mqp->qp;
  71
  72         /* Notify ipath_destroy_qp() if it is waiting. */
  73         if (atomic_dec_and_test(&qp->refcount))
  74                 wake_up(&qp->wait);
  75
  76         kfree(mqp);
  77 }
  78
  79 /**
  80  * ipath_mcast_alloc - allocate the multicast GID structure
  81  * @mgid: the multicast GID
  82  *
  83  * A list of QPs will be attached to this structure.
  84  */
  85 static struct ipath_mcast *ipath_mcast_alloc(union ib_gid *mgid)
  86 {
  87         struct ipath_mcast *mcast;
  88
  89         mcast = kmalloc(sizeof *mcast, GFP_KERNEL);
  90         if (!mcast)
  91                 goto bail;
  92
  93         mcast->mgid = *mgid;
  94         INIT_LIST_HEAD(&mcast->qp_list);
  95         init_waitqueue_head(&mcast->wait);
  96         atomic_set(&mcast->refcount, 0);
  97         mcast->n_attached = 0;
  98
  99 bail:
 100         return mcast;
 101 }
 102
 103 static void ipath_mcast_free(struct ipath_mcast *mcast)
 104 {
 105         struct ipath_mcast_qp *p, *tmp;
 106
 107         list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
 108                 ipath_mcast_qp_free(p);
 109
 110         kfree(mcast);
 111 }
 112
 113 /**
 114  * ipath_mcast_find - search the global table for the given multicast GID
 115  * @mgid: the multicast GID to search for
 116  *
 117  * Returns NULL if not found.
 118  *
 119  * The caller is responsible for decrementing the reference count if found.
 120  */
 121 struct ipath_mcast *ipath_mcast_find(union ib_gid *mgid)
 122 {
 123         struct rb_node *n;
 124         unsigned long flags;
 125         struct ipath_mcast *mcast;
 126
 127         spin_lock_irqsave(&mcast_lock, flags);
 128         n = mcast_tree.rb_node;
 129         while (n) {
 130                 int ret;
 131
 132                 mcast = rb_entry(n, struct ipath_mcast, rb_node);
 133
 134                 ret = memcmp(mgid->raw, mcast->mgid.raw,
 135                              sizeof(union ib_gid));
 136                 if (ret < 0)
 137                         n = n->rb_left;
 138                 else if (ret > 0)
 139                         n = n->rb_right;
 140                 else {
 141                         atomic_inc(&mcast->refcount);
 142                         spin_unlock_irqrestore(&mcast_lock, flags);
 143                         goto bail;
 144                 }
 145         }
 146         spin_unlock_irqrestore(&mcast_lock, flags);
 147
 148         mcast = NULL;
 149
 150 bail:
 151         return mcast;
 152 }
 153
 154 /**
 155  * ipath_mcast_add - insert mcast GID into table and attach QP struct
 156  * @mcast: the mcast GID table
 157  * @mqp: the QP to attach
 158  *
 159  * Return zero if both were added.  Return EEXIST if the GID was already in
 160  * the table but the QP was added.  Return ESRCH if the QP was already
 161  * attached and neither structure was added.
 162  */
 163 static int ipath_mcast_add(struct ipath_ibdev *dev,
 164                            struct ipath_mcast *mcast,
 165                            struct ipath_mcast_qp *mqp)
 166 {
 167         struct rb_node **n = &mcast_tree.rb_node;
 168         struct rb_node *pn = NULL;
 169         int ret;
 170
 171         spin_lock_irq(&mcast_lock);
 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         spin_lock(&dev->n_mcast_grps_lock);
 211         if (dev->n_mcast_grps_allocated == ib_ipath_max_mcast_grps) {
 212                 spin_unlock(&dev->n_mcast_grps_lock);
 213                 ret = ENOMEM;
 214                 goto bail;
 215         }
 216
 217         dev->n_mcast_grps_allocated++;
 218         spin_unlock(&dev->n_mcast_grps_lock);
 219
 220         mcast->n_attached++;
 221
 222         list_add_tail_rcu(&mqp->list, &mcast->qp_list);
 223
 224         atomic_inc(&mcast->refcount);
 225         rb_link_node(&mcast->rb_node, pn, n);
 226         rb_insert_color(&mcast->rb_node, &mcast_tree);
 227
 228         ret = 0;
 229
 230 bail:
 231         spin_unlock_irq(&mcast_lock);
 232
 233         return ret;
 234 }
 235
 236 int ipath_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 237 {
 238         struct ipath_qp *qp = to_iqp(ibqp);
 239         struct ipath_ibdev *dev = to_idev(ibqp->device);
 240         struct ipath_mcast *mcast;
 241         struct ipath_mcast_qp *mqp;
 242         int ret;
 243
 244         /*
 245          * Allocate data structures since its better to do this outside of
 246          * spin locks and it will most likely be needed.
 247          */
 248         mcast = ipath_mcast_alloc(gid);
 249         if (mcast == NULL) {
 250                 ret = -ENOMEM;
 251                 goto bail;
 252         }
 253         mqp = ipath_mcast_qp_alloc(qp);
 254         if (mqp == NULL) {
 255                 ipath_mcast_free(mcast);
 256                 ret = -ENOMEM;
 257                 goto bail;
 258         }
 259         switch (ipath_mcast_add(dev, mcast, mqp)) {
 260         case ESRCH:
 261                 /* Neither was used: can't attach the same QP twice. */
 262                 ipath_mcast_qp_free(mqp);
 263                 ipath_mcast_free(mcast);
 264                 ret = -EINVAL;
 265                 goto bail;
 266         case EEXIST:            /* The mcast wasn't used */
 267                 ipath_mcast_free(mcast);
 268                 break;
 269         case ENOMEM:
 270                 /* Exceeded the maximum number of mcast groups. */
 271                 ipath_mcast_qp_free(mqp);
 272                 ipath_mcast_free(mcast);
 273                 ret = -ENOMEM;
 274                 goto bail;
 275         default:
 276                 break;
 277         }
 278
 279         ret = 0;
 280
 281 bail:
 282         return ret;
 283 }
 284
 285 int ipath_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 286 {
 287         struct ipath_qp *qp = to_iqp(ibqp);
 288         struct ipath_ibdev *dev = to_idev(ibqp->device);
 289         struct ipath_mcast *mcast = NULL;
 290         struct ipath_mcast_qp *p, *tmp;
 291         struct rb_node *n;
 292         int last = 0;
 293         int ret;
 294
 295         spin_lock_irq(&mcast_lock);
 296
 297         /* Find the GID in the mcast table. */
 298         n = mcast_tree.rb_node;
 299         while (1) {
 300                 if (n == NULL) {
 301                         spin_unlock_irq(&mcast_lock);
 302                         ret = -EINVAL;
 303                         goto bail;
 304                 }
 305
 306                 mcast = rb_entry(n, struct ipath_mcast, rb_node);
 307                 ret = memcmp(gid->raw, mcast->mgid.raw,
 308                              sizeof(union ib_gid));
 309                 if (ret < 0)
 310                         n = n->rb_left;
 311                 else if (ret > 0)
 312                         n = n->rb_right;
 313                 else
 314                         break;
 315         }
 316
 317         /* Search the QP list. */
 318         list_for_each_entry_safe(p, tmp, &mcast->qp_list, list) {
 319                 if (p->qp != qp)
 320                         continue;
 321                 /*
 322                  * We found it, so remove it, but don't poison the forward
 323                  * link until we are sure there are no list walkers.
 324                  */
 325                 list_del_rcu(&p->list);
 326                 mcast->n_attached--;
 327
 328                 /* If this was the last attached QP, remove the GID too. */
 329                 if (list_empty(&mcast->qp_list)) {
 330                         rb_erase(&mcast->rb_node, &mcast_tree);
 331                         last = 1;
 332                 }
 333                 break;
 334         }
 335
 336         spin_unlock_irq(&mcast_lock);
 337
 338         if (p) {
 339                 /*
 340                  * Wait for any list walkers to finish before freeing the
 341                  * list element.
 342                  */
 343                 wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
 344                 ipath_mcast_qp_free(p);
 345         }
 346         if (last) {
 347                 atomic_dec(&mcast->refcount);
 348                 wait_event(mcast->wait, !atomic_read(&mcast->refcount));
 349                 ipath_mcast_free(mcast);
 350                 spin_lock_irq(&dev->n_mcast_grps_lock);
 351                 dev->n_mcast_grps_allocated--;
 352                 spin_unlock_irq(&dev->n_mcast_grps_lock);
 353         }
 354
 355         ret = 0;
 356
 357 bail:
 358         return ret;
 359 }
 360
 361 int ipath_mcast_tree_empty(void)
 362 {
 363         return mcast_tree.rb_node == NULL;
 364 }