IB/ipath: infiniband verbs support

The ipath_verbs.c file implements the driver-specific components of the
kernel's Infiniband verbs layer.

Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ipath/ipath_verbs_mcast.c

@@ -0,0 +1,333 @@
+/*
+ * 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/list.h>
+#include <linux/rcupdate.h>
+
+#include "ipath_verbs.h"
+
+/*
+ * Global table of GID to attached QPs.
+ * The table is global to all ipath devices since a send from one QP/device
+ * needs to be locally routed to any locally attached QPs on the same
+ * or different device.
+ */
+static struct rb_root mcast_tree;
+static DEFINE_SPINLOCK(mcast_lock);
+
+/**
+ * ipath_mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
+ * @qp: the QP to link
+ */
+static struct ipath_mcast_qp *ipath_mcast_qp_alloc(struct ipath_qp *qp)
+{
+	struct ipath_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 ipath_mcast_qp_free(struct ipath_mcast_qp *mqp)
+{
+	struct ipath_qp *qp = mqp->qp;
+
+	/* Notify ipath_destroy_qp() if it is waiting. */
+	if (atomic_dec_and_test(&qp->refcount))
+		wake_up(&qp->wait);
+
+	kfree(mqp);
+}
+
+/**
+ * ipath_mcast_alloc - allocate the multicast GID structure
+ * @mgid: the multicast GID
+ *
+ * A list of QPs will be attached to this structure.
+ */
+static struct ipath_mcast *ipath_mcast_alloc(union ib_gid *mgid)
+{
+	struct ipath_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);
+
+bail:
+	return mcast;
+}
+
+static void ipath_mcast_free(struct ipath_mcast *mcast)
+{
+	struct ipath_mcast_qp *p, *tmp;
+
+	list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
+		ipath_mcast_qp_free(p);
+
+	kfree(mcast);
+}
+
+/**
+ * ipath_mcast_find - search the global table for the given multicast GID
+ * @mgid: the multicast GID to search for
+ *
+ * Returns NULL if not found.
+ *
+ * The caller is responsible for decrementing the reference count if found.
+ */
+struct ipath_mcast *ipath_mcast_find(union ib_gid *mgid)
+{
+	struct rb_node *n;
+	unsigned long flags;
+	struct ipath_mcast *mcast;
+
+	spin_lock_irqsave(&mcast_lock, flags);
+	n = mcast_tree.rb_node;
+	while (n) {
+		int ret;
+
+		mcast = rb_entry(n, struct ipath_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(&mcast_lock, flags);
+			goto bail;
+		}
+	}
+	spin_unlock_irqrestore(&mcast_lock, flags);
+
+	mcast = NULL;
+
+bail:
+	return mcast;
+}
+
+/**
+ * ipath_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 ipath_mcast_add(struct ipath_mcast *mcast,
+			   struct ipath_mcast_qp *mqp)
+{
+	struct rb_node **n = &mcast_tree.rb_node;
+	struct rb_node *pn = NULL;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&mcast_lock, flags);
+
+	while (*n) {
+		struct ipath_mcast *tmcast;
+		struct ipath_mcast_qp *p;
+
+		pn = *n;
+		tmcast = rb_entry(pn, struct ipath_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) {
+				spin_unlock_irqrestore(&mcast_lock, flags);
+				ret = ESRCH;
+				goto bail;
+			}
+		}
+		list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
+		spin_unlock_irqrestore(&mcast_lock, flags);
+		ret = EEXIST;
+		goto bail;
+	}
+
+	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, &mcast_tree);
+
+	spin_unlock_irqrestore(&mcast_lock, flags);
+
+	ret = 0;
+
+bail:
+	return ret;
+}
+
+int ipath_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
+{
+	struct ipath_qp *qp = to_iqp(ibqp);
+	struct ipath_mcast *mcast;
+	struct ipath_mcast_qp *mqp;
+	int ret;
+
+	/*
+	 * Allocate data structures since its better to do this outside of
+	 * spin locks and it will most likely be needed.
+	 */
+	mcast = ipath_mcast_alloc(gid);
+	if (mcast == NULL) {
+		ret = -ENOMEM;
+		goto bail;
+	}
+	mqp = ipath_mcast_qp_alloc(qp);
+	if (mqp == NULL) {
+		ipath_mcast_free(mcast);
+		ret = -ENOMEM;
+		goto bail;
+	}
+	switch (ipath_mcast_add(mcast, mqp)) {
+	case ESRCH:
+		/* Neither was used: can't attach the same QP twice. */
+		ipath_mcast_qp_free(mqp);
+		ipath_mcast_free(mcast);
+		ret = -EINVAL;
+		goto bail;
+	case EEXIST:		/* The mcast wasn't used */
+		ipath_mcast_free(mcast);
+		break;
+	default:
+		break;
+	}
+
+	ret = 0;
+
+bail:
+	return ret;
+}
+
+int ipath_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
+{
+	struct ipath_qp *qp = to_iqp(ibqp);
+	struct ipath_mcast *mcast = NULL;
+	struct ipath_mcast_qp *p, *tmp;
+	struct rb_node *n;
+	unsigned long flags;
+	int last = 0;
+	int ret;
+
+	spin_lock_irqsave(&mcast_lock, flags);
+
+	/* Find the GID in the mcast table. */
+	n = mcast_tree.rb_node;
+	while (1) {
+		if (n == NULL) {
+			spin_unlock_irqrestore(&mcast_lock, flags);
+			ret = 0;
+			goto bail;
+		}
+
+		mcast = rb_entry(n, struct ipath_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);
+
+		/* If this was the last attached QP, remove the GID too. */
+		if (list_empty(&mcast->qp_list)) {
+			rb_erase(&mcast->rb_node, &mcast_tree);
+			last = 1;
+		}
+		break;
+	}
+
+	spin_unlock_irqrestore(&mcast_lock, flags);
+
+	if (p) {
+		/*
+		 * Wait for any list walkers to finish before freeing the
+		 * list element.
+		 */
+		wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
+		ipath_mcast_qp_free(p);
+	}
+	if (last) {
+		atomic_dec(&mcast->refcount);
+		wait_event(mcast->wait, !atomic_read(&mcast->refcount));
+		ipath_mcast_free(mcast);
+	}
+
+	ret = 0;
+
+bail:
+	return ret;
+}
+
+int ipath_mcast_tree_empty(void)
+{
+	return mcast_tree.rb_node == NULL;
+}