1 files changed, 479 insertions, 0 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
new file mode 100644
index 000000000..86cc2e18a
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
@@ -0,0 +1,479 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2022 Hewlett Packard Enterprise, Inc. All rights reserved.
+ * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
+ */
+
+/*
+ * rxe_mcast.c implements driver support for multicast transport.
+ * It is based on two data structures struct rxe_mcg ('mcg') and
+ * struct rxe_mca ('mca'). An mcg is allocated each time a qp is
+ * attached to a new mgid for the first time. These are indexed by
+ * a red-black tree using the mgid. This data structure is searched
+ * for the mcg when a multicast packet is received and when another
+ * qp is attached to the same mgid. It is cleaned up when the last qp
+ * is detached from the mcg. Each time a qp is attached to an mcg an
+ * mca is created. It holds a pointer to the qp and is added to a list
+ * of qp's that are attached to the mcg. The qp_list is used to replicate
+ * mcast packets in the rxe receive path.
+ */
+
+#include "rxe.h"
+
+/**
+ * rxe_mcast_add - add multicast address to rxe device
+ * @rxe: rxe device object
+ * @mgid: multicast address as a gid
+ *
+ * Returns 0 on success else an error
+ */
+static int rxe_mcast_add(struct rxe_dev *rxe, union ib_gid *mgid)
+{
+	unsigned char ll_addr[ETH_ALEN];
+
+	ipv6_eth_mc_map((struct in6_addr *)mgid->raw, ll_addr);
+
+	return dev_mc_add(rxe->ndev, ll_addr);
+}
+
+/**
+ * rxe_mcast_del - delete multicast address from rxe device
+ * @rxe: rxe device object
+ * @mgid: multicast address as a gid
+ *
+ * Returns 0 on success else an error
+ */
+static int rxe_mcast_del(struct rxe_dev *rxe, union ib_gid *mgid)
+{
+	unsigned char ll_addr[ETH_ALEN];
+
+	ipv6_eth_mc_map((struct in6_addr *)mgid->raw, ll_addr);
+
+	return dev_mc_del(rxe->ndev, ll_addr);
+}
+
+/**
+ * __rxe_insert_mcg - insert an mcg into red-black tree (rxe->mcg_tree)
+ * @mcg: mcg object with an embedded red-black tree node
+ *
+ * Context: caller must hold a reference to mcg and rxe->mcg_lock and
+ * is responsible to avoid adding the same mcg twice to the tree.
+ */
+static void __rxe_insert_mcg(struct rxe_mcg *mcg)
+{
+	struct rb_root *tree = &mcg->rxe->mcg_tree;
+	struct rb_node **link = &tree->rb_node;
+	struct rb_node *node = NULL;
+	struct rxe_mcg *tmp;
+	int cmp;
+
+	while (*link) {
+		node = *link;
+		tmp = rb_entry(node, struct rxe_mcg, node);
+
+		cmp = memcmp(&tmp->mgid, &mcg->mgid, sizeof(mcg->mgid));
+		if (cmp > 0)
+			link = &(*link)->rb_left;
+		else
+			link = &(*link)->rb_right;
+	}
+
+	rb_link_node(&mcg->node, node, link);
+	rb_insert_color(&mcg->node, tree);
+}
+
+/**
+ * __rxe_remove_mcg - remove an mcg from red-black tree holding lock
+ * @mcg: mcast group object with an embedded red-black tree node
+ *
+ * Context: caller must hold a reference to mcg and rxe->mcg_lock
+ */
+static void __rxe_remove_mcg(struct rxe_mcg *mcg)
+{
+	rb_erase(&mcg->node, &mcg->rxe->mcg_tree);
+}
+
+/**
+ * __rxe_lookup_mcg - lookup mcg in rxe->mcg_tree while holding lock
+ * @rxe: rxe device object
+ * @mgid: multicast IP address
+ *
+ * Context: caller must hold rxe->mcg_lock
+ * Returns: mcg on success and takes a ref to mcg else NULL
+ */
+static struct rxe_mcg *__rxe_lookup_mcg(struct rxe_dev *rxe,
+					union ib_gid *mgid)
+{
+	struct rb_root *tree = &rxe->mcg_tree;
+	struct rxe_mcg *mcg;
+	struct rb_node *node;
+	int cmp;
+
+	node = tree->rb_node;
+
+	while (node) {
+		mcg = rb_entry(node, struct rxe_mcg, node);
+
+		cmp = memcmp(&mcg->mgid, mgid, sizeof(*mgid));
+
+		if (cmp > 0)
+			node = node->rb_left;
+		else if (cmp < 0)
+			node = node->rb_right;
+		else
+			break;
+	}
+
+	if (node) {
+		kref_get(&mcg->ref_cnt);
+		return mcg;
+	}
+
+	return NULL;
+}
+
+/**
+ * rxe_lookup_mcg - lookup up mcg in red-back tree
+ * @rxe: rxe device object
+ * @mgid: multicast IP address
+ *
+ * Returns: mcg if found else NULL
+ */
+struct rxe_mcg *rxe_lookup_mcg(struct rxe_dev *rxe, union ib_gid *mgid)
+{
+	struct rxe_mcg *mcg;
+
+	spin_lock_bh(&rxe->mcg_lock);
+	mcg = __rxe_lookup_mcg(rxe, mgid);
+	spin_unlock_bh(&rxe->mcg_lock);
+
+	return mcg;
+}
+
+/**
+ * __rxe_init_mcg - initialize a new mcg
+ * @rxe: rxe device
+ * @mgid: multicast address as a gid
+ * @mcg: new mcg object
+ *
+ * Context: caller should hold rxe->mcg lock
+ */
+static void __rxe_init_mcg(struct rxe_dev *rxe, union ib_gid *mgid,
+			   struct rxe_mcg *mcg)
+{
+	kref_init(&mcg->ref_cnt);
+	memcpy(&mcg->mgid, mgid, sizeof(mcg->mgid));
+	INIT_LIST_HEAD(&mcg->qp_list);
+	mcg->rxe = rxe;
+
+	/* caller holds a ref on mcg but that will be
+	 * dropped when mcg goes out of scope. We need to take a ref
+	 * on the pointer that will be saved in the red-black tree
+	 * by __rxe_insert_mcg and used to lookup mcg from mgid later.
+	 * Inserting mcg makes it visible to outside so this should
+	 * be done last after the object is ready.
+	 */
+	kref_get(&mcg->ref_cnt);
+	__rxe_insert_mcg(mcg);
+}
+
+/**
+ * rxe_get_mcg - lookup or allocate a mcg
+ * @rxe: rxe device object
+ * @mgid: multicast IP address as a gid
+ *
+ * Returns: mcg on success else ERR_PTR(error)
+ */
+static struct rxe_mcg *rxe_get_mcg(struct rxe_dev *rxe, union ib_gid *mgid)
+{
+	struct rxe_mcg *mcg, *tmp;
+	int err;
+
+	if (rxe->attr.max_mcast_grp == 0)
+		return ERR_PTR(-EINVAL);
+
+	/* check to see if mcg already exists */
+	mcg = rxe_lookup_mcg(rxe, mgid);
+	if (mcg)
+		return mcg;
+
+	/* check to see if we have reached limit */
+	if (atomic_inc_return(&rxe->mcg_num) > rxe->attr.max_mcast_grp) {
+		err = -ENOMEM;
+		goto err_dec;
+	}
+
+	/* speculative alloc of new mcg */
+	mcg = kzalloc(sizeof(*mcg), GFP_KERNEL);
+	if (!mcg) {
+		err = -ENOMEM;
+		goto err_dec;
+	}
+
+	spin_lock_bh(&rxe->mcg_lock);
+	/* re-check to see if someone else just added it */
+	tmp = __rxe_lookup_mcg(rxe, mgid);
+	if (tmp) {
+		spin_unlock_bh(&rxe->mcg_lock);
+		atomic_dec(&rxe->mcg_num);
+		kfree(mcg);
+		return tmp;
+	}
+
+	__rxe_init_mcg(rxe, mgid, mcg);
+	spin_unlock_bh(&rxe->mcg_lock);
+
+	/* add mcast address outside of lock */
+	err = rxe_mcast_add(rxe, mgid);
+	if (!err)
+		return mcg;
+
+	kfree(mcg);
+err_dec:
+	atomic_dec(&rxe->mcg_num);
+	return ERR_PTR(err);
+}
+
+/**
+ * rxe_cleanup_mcg - cleanup mcg for kref_put
+ * @kref: struct kref embnedded in mcg
+ */
+void rxe_cleanup_mcg(struct kref *kref)
+{
+	struct rxe_mcg *mcg = container_of(kref, typeof(*mcg), ref_cnt);
+
+	kfree(mcg);
+}
+
+/**
+ * __rxe_destroy_mcg - destroy mcg object holding rxe->mcg_lock
+ * @mcg: the mcg object
+ *
+ * Context: caller is holding rxe->mcg_lock
+ * no qp's are attached to mcg
+ */
+static void __rxe_destroy_mcg(struct rxe_mcg *mcg)
+{
+	struct rxe_dev *rxe = mcg->rxe;
+
+	/* remove mcg from red-black tree then drop ref */
+	__rxe_remove_mcg(mcg);
+	kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
+
+	atomic_dec(&rxe->mcg_num);
+}
+
+/**
+ * rxe_destroy_mcg - destroy mcg object
+ * @mcg: the mcg object
+ *
+ * Context: no qp's are attached to mcg
+ */
+static void rxe_destroy_mcg(struct rxe_mcg *mcg)
+{
+	/* delete mcast address outside of lock */
+	rxe_mcast_del(mcg->rxe, &mcg->mgid);
+
+	spin_lock_bh(&mcg->rxe->mcg_lock);
+	__rxe_destroy_mcg(mcg);
+	spin_unlock_bh(&mcg->rxe->mcg_lock);
+}
+
+/**
+ * __rxe_init_mca - initialize a new mca holding lock
+ * @qp: qp object
+ * @mcg: mcg object
+ * @mca: empty space for new mca
+ *
+ * Context: caller must hold references on qp and mcg, rxe->mcg_lock
+ * and pass memory for new mca
+ *
+ * Returns: 0 on success else an error
+ */
+static int __rxe_init_mca(struct rxe_qp *qp, struct rxe_mcg *mcg,
+			  struct rxe_mca *mca)
+{
+	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+	int n;
+
+	n = atomic_inc_return(&rxe->mcg_attach);
+	if (n > rxe->attr.max_total_mcast_qp_attach) {
+		atomic_dec(&rxe->mcg_attach);
+		return -ENOMEM;
+	}
+
+	n = atomic_inc_return(&mcg->qp_num);
+	if (n > rxe->attr.max_mcast_qp_attach) {
+		atomic_dec(&mcg->qp_num);
+		atomic_dec(&rxe->mcg_attach);
+		return -ENOMEM;
+	}
+
+	atomic_inc(&qp->mcg_num);
+
+	rxe_get(qp);
+	mca->qp = qp;
+
+	list_add_tail(&mca->qp_list, &mcg->qp_list);
+
+	return 0;
+}
+
+/**
+ * rxe_attach_mcg - attach qp to mcg if not already attached
+ * @qp: qp object
+ * @mcg: mcg object
+ *
+ * Context: caller must hold reference on qp and mcg.
+ * Returns: 0 on success else an error
+ */
+static int rxe_attach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp)
+{
+	struct rxe_dev *rxe = mcg->rxe;
+	struct rxe_mca *mca, *tmp;
+	int err;
+
+	/* check to see if the qp is already a member of the group */
+	spin_lock_bh(&rxe->mcg_lock);
+	list_for_each_entry(mca, &mcg->qp_list, qp_list) {
+		if (mca->qp == qp) {
+			spin_unlock_bh(&rxe->mcg_lock);
+			return 0;
+		}
+	}
+	spin_unlock_bh(&rxe->mcg_lock);
+
+	/* speculative alloc new mca without using GFP_ATOMIC */
+	mca = kzalloc(sizeof(*mca), GFP_KERNEL);
+	if (!mca)
+		return -ENOMEM;
+
+	spin_lock_bh(&rxe->mcg_lock);
+	/* re-check to see if someone else just attached qp */
+	list_for_each_entry(tmp, &mcg->qp_list, qp_list) {
+		if (tmp->qp == qp) {
+			kfree(mca);
+			err = 0;
+			goto out;
+		}
+	}
+
+	err = __rxe_init_mca(qp, mcg, mca);
+	if (err)
+		kfree(mca);
+out:
+	spin_unlock_bh(&rxe->mcg_lock);
+	return err;
+}
+
+/**
+ * __rxe_cleanup_mca - cleanup mca object holding lock
+ * @mca: mca object
+ * @mcg: mcg object
+ *
+ * Context: caller must hold a reference to mcg and rxe->mcg_lock
+ */
+static void __rxe_cleanup_mca(struct rxe_mca *mca, struct rxe_mcg *mcg)
+{
+	list_del(&mca->qp_list);
+
+	atomic_dec(&mcg->qp_num);
+	atomic_dec(&mcg->rxe->mcg_attach);
+	atomic_dec(&mca->qp->mcg_num);
+	rxe_put(mca->qp);
+
+	kfree(mca);
+}
+
+/**
+ * rxe_detach_mcg - detach qp from mcg
+ * @mcg: mcg object
+ * @qp: qp object
+ *
+ * Returns: 0 on success else an error if qp is not attached.
+ */
+static int rxe_detach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp)
+{
+	struct rxe_dev *rxe = mcg->rxe;
+	struct rxe_mca *mca, *tmp;
+
+	spin_lock_bh(&rxe->mcg_lock);
+	list_for_each_entry_safe(mca, tmp, &mcg->qp_list, qp_list) {
+		if (mca->qp == qp) {
+			__rxe_cleanup_mca(mca, mcg);
+
+			/* if the number of qp's attached to the
+			 * mcast group falls to zero go ahead and
+			 * tear it down. This will not free the
+			 * object since we are still holding a ref
+			 * from the caller
+			 */
+			if (atomic_read(&mcg->qp_num) <= 0)
+				__rxe_destroy_mcg(mcg);
+
+			spin_unlock_bh(&rxe->mcg_lock);
+			return 0;
+		}
+	}
+
+	/* we didn't find the qp on the list */
+	spin_unlock_bh(&rxe->mcg_lock);
+	return -EINVAL;
+}
+
+/**
+ * rxe_attach_mcast - attach qp to multicast group (see IBA-11.3.1)
+ * @ibqp: (IB) qp object
+ * @mgid: multicast IP address
+ * @mlid: multicast LID, ignored for RoCEv2 (see IBA-A17.5.6)
+ *
+ * Returns: 0 on success else an errno
+ */
+int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
+{
+	int err;
+	struct rxe_dev *rxe = to_rdev(ibqp->device);
+	struct rxe_qp *qp = to_rqp(ibqp);
+	struct rxe_mcg *mcg;
+
+	/* takes a ref on mcg if successful */
+	mcg = rxe_get_mcg(rxe, mgid);
+	if (IS_ERR(mcg))
+		return PTR_ERR(mcg);
+
+	err = rxe_attach_mcg(mcg, qp);
+
+	/* if we failed to attach the first qp to mcg tear it down */
+	if (atomic_read(&mcg->qp_num) == 0)
+		rxe_destroy_mcg(mcg);
+
+	kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
+
+	return err;
+}
+
+/**
+ * rxe_detach_mcast - detach qp from multicast group (see IBA-11.3.2)
+ * @ibqp: address of (IB) qp object
+ * @mgid: multicast IP address
+ * @mlid: multicast LID, ignored for RoCEv2 (see IBA-A17.5.6)
+ *
+ * Returns: 0 on success else an errno
+ */
+int rxe_detach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
+{
+	struct rxe_dev *rxe = to_rdev(ibqp->device);
+	struct rxe_qp *qp = to_rqp(ibqp);
+	struct rxe_mcg *mcg;
+	int err;
+
+	mcg = rxe_lookup_mcg(rxe, mgid);
+	if (!mcg)
+		return -EINVAL;
+
+	err = rxe_detach_mcg(mcg, qp);
+	kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
+
+	return err;
+}