/*
* 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;
}
