linux/drivers/infiniband/sw/rdmavt/mcast.c
Dennis Dalessandro 90793f7179 IB/rdmavt: Clean up comments and add more documentation
Add, remove, and otherwise clean up existing comments that are leftover
from the initial code postings of rdmavt. Many of the comments were added
to provide an idea on the direction we were thinking of going. Now that the
design is solidified make a pass over and clean everything up. Also add
details where lacking.

Ensure all non static functions have nano comments.

Reviewed-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-03-10 20:38:08 -05:00

418 lines
9.9 KiB
C

/*
* Copyright(c) 2016 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* BSD LICENSE
*
* 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.
* - Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/rculist.h>
#include <rdma/rdma_vt.h>
#include <rdma/rdmavt_qp.h>
#include "mcast.h"
/**
* rvt_driver_mcast - init resources for multicast
* @rdi: rvt dev struct
*
* This is per device that registers with rdmavt
*/
void rvt_driver_mcast_init(struct rvt_dev_info *rdi)
{
/*
* Anything that needs setup for multicast on a per driver or per rdi
* basis should be done in here.
*/
spin_lock_init(&rdi->n_mcast_grps_lock);
}
/**
* mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
* @qp: the QP to link
*/
static struct rvt_mcast_qp *rvt_mcast_qp_alloc(struct rvt_qp *qp)
{
struct rvt_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 rvt_mcast_qp_free(struct rvt_mcast_qp *mqp)
{
struct rvt_qp *qp = mqp->qp;
/* Notify hfi1_destroy_qp() if it is waiting. */
if (atomic_dec_and_test(&qp->refcount))
wake_up(&qp->wait);
kfree(mqp);
}
/**
* mcast_alloc - allocate the multicast GID structure
* @mgid: the multicast GID
*
* A list of QPs will be attached to this structure.
*/
static struct rvt_mcast *rvt_mcast_alloc(union ib_gid *mgid)
{
struct rvt_mcast *mcast;
mcast = kzalloc(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 rvt_mcast_free(struct rvt_mcast *mcast)
{
struct rvt_mcast_qp *p, *tmp;
list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
rvt_mcast_qp_free(p);
kfree(mcast);
}
/**
* rvt_mcast_find - search the global table for the given multicast GID
* @ibp: the IB port structure
* @mgid: the multicast GID to search for
*
* The caller is responsible for decrementing the reference count if found.
*
* Return: NULL if not found.
*/
struct rvt_mcast *rvt_mcast_find(struct rvt_ibport *ibp, union ib_gid *mgid)
{
struct rb_node *n;
unsigned long flags;
struct rvt_mcast *found = NULL;
spin_lock_irqsave(&ibp->lock, flags);
n = ibp->mcast_tree.rb_node;
while (n) {
int ret;
struct rvt_mcast *mcast;
mcast = rb_entry(n, struct rvt_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);
found = mcast;
break;
}
}
spin_unlock_irqrestore(&ibp->lock, flags);
return found;
}
EXPORT_SYMBOL(rvt_mcast_find);
/**
* 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 rvt_mcast_add(struct rvt_dev_info *rdi, struct rvt_ibport *ibp,
struct rvt_mcast *mcast, struct rvt_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 rvt_mcast *tmcast;
struct rvt_mcast_qp *p;
pn = *n;
tmcast = rb_entry(pn, struct rvt_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 ==
rdi->dparms.props.max_mcast_qp_attach) {
ret = ENOMEM;
goto bail;
}
tmcast->n_attached++;
list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
ret = EEXIST;
goto bail;
}
spin_lock(&rdi->n_mcast_grps_lock);
if (rdi->n_mcast_grps_allocated == rdi->dparms.props.max_mcast_grp) {
spin_unlock(&rdi->n_mcast_grps_lock);
ret = ENOMEM;
goto bail;
}
rdi->n_mcast_grps_allocated++;
spin_unlock(&rdi->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;
}
/**
* rvt_attach_mcast - attach a qp to a multicast group
* @ibqp: Infiniband qp
* @igd: multicast guid
* @lid: multicast lid
*
* Return: 0 on success
*/
int rvt_attach_mcast(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
{
struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);
struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
struct rvt_ibport *ibp = rdi->ports[qp->port_num - 1];
struct rvt_mcast *mcast;
struct rvt_mcast_qp *mqp;
int ret = -ENOMEM;
if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET)
return -EINVAL;
/*
* Allocate data structures since its better to do this outside of
* spin locks and it will most likely be needed.
*/
mcast = rvt_mcast_alloc(gid);
if (!mcast)
return -ENOMEM;
mqp = rvt_mcast_qp_alloc(qp);
if (!mqp)
goto bail_mcast;
switch (rvt_mcast_add(rdi, ibp, mcast, mqp)) {
case ESRCH:
/* Neither was used: OK to attach the same QP twice. */
ret = 0;
goto bail_mqp;
case EEXIST: /* The mcast wasn't used */
ret = 0;
goto bail_mcast;
case ENOMEM:
/* Exceeded the maximum number of mcast groups. */
ret = -ENOMEM;
goto bail_mqp;
default:
break;
}
return 0;
bail_mqp:
rvt_mcast_qp_free(mqp);
bail_mcast:
rvt_mcast_free(mcast);
return ret;
}
/**
* rvt_detach_mcast - remove a qp from a multicast group
* @ibqp: Infiniband qp
* @igd: multicast guid
* @lid: multicast lid
*
* Return: 0 on success
*/
int rvt_detach_mcast(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
{
struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);
struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
struct rvt_ibport *ibp = rdi->ports[qp->port_num - 1];
struct rvt_mcast *mcast = NULL;
struct rvt_mcast_qp *p, *tmp, *delp = NULL;
struct rb_node *n;
int last = 0;
int ret = 0;
if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET)
return -EINVAL;
spin_lock_irq(&ibp->lock);
/* Find the GID in the mcast table. */
n = ibp->mcast_tree.rb_node;
while (1) {
if (!n) {
spin_unlock_irq(&ibp->lock);
return -EINVAL;
}
mcast = rb_entry(n, struct rvt_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--;
delp = p;
/* 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);
/* QP not attached */
if (!delp)
return -EINVAL;
/*
* Wait for any list walkers to finish before freeing the
* list element.
*/
wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
rvt_mcast_qp_free(delp);
if (last) {
atomic_dec(&mcast->refcount);
wait_event(mcast->wait, !atomic_read(&mcast->refcount));
rvt_mcast_free(mcast);
spin_lock_irq(&rdi->n_mcast_grps_lock);
rdi->n_mcast_grps_allocated--;
spin_unlock_irq(&rdi->n_mcast_grps_lock);
}
return 0;
}
/**
*rvt_mast_tree_empty - determine if any qps are attached to any mcast group
*@rdi: rvt dev struct
*
* Return: in use count
*/
int rvt_mcast_tree_empty(struct rvt_dev_info *rdi)
{
int i;
int in_use = 0;
for (i = 0; i < rdi->dparms.nports; i++)
if (rdi->ports[i]->mcast_tree.rb_node)
in_use++;
return in_use;
}