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+/*
+ * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
+ * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/rculist.h>
+
+#include "qib.h"
+
+/**
+ * qib_mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
+ * @qp: the QP to link
+ */
+static struct qib_mcast_qp *qib_mcast_qp_alloc(struct qib_qp *qp)
+{
+ struct qib_mcast_qp *mqp;
+
+ mqp = kmalloc(sizeof *mqp, GFP_KERNEL);
+ if (!mqp)
+ goto bail;
+
+ mqp->qp = qp;
+ atomic_inc(&qp->refcount);
+
+bail:
+ return mqp;
+}
+
+static void qib_mcast_qp_free(struct qib_mcast_qp *mqp)
+{
+ struct qib_qp *qp = mqp->qp;
+
+ /* Notify qib_destroy_qp() if it is waiting. */
+ if (atomic_dec_and_test(&qp->refcount))
+ wake_up(&qp->wait);
+
+ kfree(mqp);
+}
+
+/**
+ * qib_mcast_alloc - allocate the multicast GID structure
+ * @mgid: the multicast GID
+ *
+ * A list of QPs will be attached to this structure.
+ */
+static struct qib_mcast *qib_mcast_alloc(union ib_gid *mgid)
+{
+ struct qib_mcast *mcast;
+
+ mcast = kmalloc(sizeof *mcast, GFP_KERNEL);
+ if (!mcast)
+ goto bail;
+
+ mcast->mgid = *mgid;
+ INIT_LIST_HEAD(&mcast->qp_list);
+ init_waitqueue_head(&mcast->wait);
+ atomic_set(&mcast->refcount, 0);
+ mcast->n_attached = 0;
+
+bail:
+ return mcast;
+}
+
+static void qib_mcast_free(struct qib_mcast *mcast)
+{
+ struct qib_mcast_qp *p, *tmp;
+
+ list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
+ qib_mcast_qp_free(p);
+
+ kfree(mcast);
+}
+
+/**
+ * qib_mcast_find - search the global table for the given multicast GID
+ * @ibp: the IB port structure
+ * @mgid: the multicast GID to search for
+ *
+ * Returns NULL if not found.
+ *
+ * The caller is responsible for decrementing the reference count if found.
+ */
+struct qib_mcast *qib_mcast_find(struct qib_ibport *ibp, union ib_gid *mgid)
+{
+ struct rb_node *n;
+ unsigned long flags;
+ struct qib_mcast *mcast;
+
+ spin_lock_irqsave(&ibp->lock, flags);
+ n = ibp->mcast_tree.rb_node;
+ while (n) {
+ int ret;
+
+ mcast = rb_entry(n, struct qib_mcast, rb_node);
+
+ ret = memcmp(mgid->raw, mcast->mgid.raw,
+ sizeof(union ib_gid));
+ if (ret < 0)
+ n = n->rb_left;
+ else if (ret > 0)
+ n = n->rb_right;
+ else {
+ atomic_inc(&mcast->refcount);
+ spin_unlock_irqrestore(&ibp->lock, flags);
+ goto bail;
+ }
+ }
+ spin_unlock_irqrestore(&ibp->lock, flags);
+
+ mcast = NULL;
+
+bail:
+ return mcast;
+}
+
+/**
+ * qib_mcast_add - insert mcast GID into table and attach QP struct
+ * @mcast: the mcast GID table
+ * @mqp: the QP to attach
+ *
+ * Return zero if both were added. Return EEXIST if the GID was already in
+ * the table but the QP was added. Return ESRCH if the QP was already
+ * attached and neither structure was added.
+ */
+static int qib_mcast_add(struct qib_ibdev *dev, struct qib_ibport *ibp,
+ struct qib_mcast *mcast, struct qib_mcast_qp *mqp)
+{
+ struct rb_node **n = &ibp->mcast_tree.rb_node;
+ struct rb_node *pn = NULL;
+ int ret;
+
+ spin_lock_irq(&ibp->lock);
+
+ while (*n) {
+ struct qib_mcast *tmcast;
+ struct qib_mcast_qp *p;
+
+ pn = *n;
+ tmcast = rb_entry(pn, struct qib_mcast, rb_node);
+
+ ret = memcmp(mcast->mgid.raw, tmcast->mgid.raw,
+ sizeof(union ib_gid));
+ if (ret < 0) {
+ n = &pn->rb_left;
+ continue;
+ }
+ if (ret > 0) {
+ n = &pn->rb_right;
+ continue;
+ }
+
+ /* Search the QP list to see if this is already there. */
+ list_for_each_entry_rcu(p, &tmcast->qp_list, list) {
+ if (p->qp == mqp->qp) {
+ ret = ESRCH;
+ goto bail;
+ }
+ }
+ if (tmcast->n_attached == ib_qib_max_mcast_qp_attached) {
+ ret = ENOMEM;
+ goto bail;
+ }
+
+ tmcast->n_attached++;
+
+ list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
+ ret = EEXIST;
+ goto bail;
+ }
+
+ spin_lock(&dev->n_mcast_grps_lock);
+ if (dev->n_mcast_grps_allocated == ib_qib_max_mcast_grps) {
+ spin_unlock(&dev->n_mcast_grps_lock);
+ ret = ENOMEM;
+ goto bail;
+ }
+
+ dev->n_mcast_grps_allocated++;
+ spin_unlock(&dev->n_mcast_grps_lock);
+
+ mcast->n_attached++;
+
+ list_add_tail_rcu(&mqp->list, &mcast->qp_list);
+
+ atomic_inc(&mcast->refcount);
+ rb_link_node(&mcast->rb_node, pn, n);
+ rb_insert_color(&mcast->rb_node, &ibp->mcast_tree);
+
+ ret = 0;
+
+bail:
+ spin_unlock_irq(&ibp->lock);
+
+ return ret;
+}
+
+int qib_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
+{
+ struct qib_qp *qp = to_iqp(ibqp);
+ struct qib_ibdev *dev = to_idev(ibqp->device);
+ struct qib_ibport *ibp;
+ struct qib_mcast *mcast;
+ struct qib_mcast_qp *mqp;
+ int ret;
+
+ if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET) {
+ ret = -EINVAL;
+ goto bail;
+ }
+
+ /*
+ * Allocate data structures since its better to do this outside of
+ * spin locks and it will most likely be needed.
+ */
+ mcast = qib_mcast_alloc(gid);
+ if (mcast == NULL) {
+ ret = -ENOMEM;
+ goto bail;
+ }
+ mqp = qib_mcast_qp_alloc(qp);
+ if (mqp == NULL) {
+ qib_mcast_free(mcast);
+ ret = -ENOMEM;
+ goto bail;
+ }
+ ibp = to_iport(ibqp->device, qp->port_num);
+ switch (qib_mcast_add(dev, ibp, mcast, mqp)) {
+ case ESRCH:
+ /* Neither was used: OK to attach the same QP twice. */
+ qib_mcast_qp_free(mqp);
+ qib_mcast_free(mcast);
+ break;
+
+ case EEXIST: /* The mcast wasn't used */
+ qib_mcast_free(mcast);
+ break;
+
+ case ENOMEM:
+ /* Exceeded the maximum number of mcast groups. */
+ qib_mcast_qp_free(mqp);
+ qib_mcast_free(mcast);
+ ret = -ENOMEM;
+ goto bail;
+
+ default:
+ break;
+ }
+
+ ret = 0;
+
+bail:
+ return ret;
+}
+
+int qib_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
+{
+ struct qib_qp *qp = to_iqp(ibqp);
+ struct qib_ibdev *dev = to_idev(ibqp->device);
+ struct qib_ibport *ibp = to_iport(ibqp->device, qp->port_num);
+ struct qib_mcast *mcast = NULL;
+ struct qib_mcast_qp *p, *tmp;
+ struct rb_node *n;
+ int last = 0;
+ int ret;
+
+ if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET) {
+ ret = -EINVAL;
+ goto bail;
+ }
+
+ spin_lock_irq(&ibp->lock);
+
+ /* Find the GID in the mcast table. */
+ n = ibp->mcast_tree.rb_node;
+ while (1) {
+ if (n == NULL) {
+ spin_unlock_irq(&ibp->lock);
+ ret = -EINVAL;
+ goto bail;
+ }
+
+ mcast = rb_entry(n, struct qib_mcast, rb_node);
+ ret = memcmp(gid->raw, mcast->mgid.raw,
+ sizeof(union ib_gid));
+ if (ret < 0)
+ n = n->rb_left;
+ else if (ret > 0)
+ n = n->rb_right;
+ else
+ break;
+ }
+
+ /* Search the QP list. */
+ list_for_each_entry_safe(p, tmp, &mcast->qp_list, list) {
+ if (p->qp != qp)
+ continue;
+ /*
+ * We found it, so remove it, but don't poison the forward
+ * link until we are sure there are no list walkers.
+ */
+ list_del_rcu(&p->list);
+ mcast->n_attached--;
+
+ /* If this was the last attached QP, remove the GID too. */
+ if (list_empty(&mcast->qp_list)) {
+ rb_erase(&mcast->rb_node, &ibp->mcast_tree);
+ last = 1;
+ }
+ break;
+ }
+
+ spin_unlock_irq(&ibp->lock);
+
+ if (p) {
+ /*
+ * Wait for any list walkers to finish before freeing the
+ * list element.
+ */
+ wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
+ qib_mcast_qp_free(p);
+ }
+ if (last) {
+ atomic_dec(&mcast->refcount);
+ wait_event(mcast->wait, !atomic_read(&mcast->refcount));
+ qib_mcast_free(mcast);
+ spin_lock_irq(&dev->n_mcast_grps_lock);
+ dev->n_mcast_grps_allocated--;
+ spin_unlock_irq(&dev->n_mcast_grps_lock);
+ }
+
+ ret = 0;
+
+bail:
+ return ret;
+}
+
+int qib_mcast_tree_empty(struct qib_ibport *ibp)
+{
+ return ibp->mcast_tree.rb_node == NULL;
+}