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// 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;
}