linux/drivers/infiniband/core/iwcm.c
Steve Wise 3eae7c9f97 RDMA/iwcm: Reject connect requests if cmid is not in LISTEN state
When destroying a listening cmid, the iwcm first marks the state of
the cmid as DESTROYING, then releases the lock and calls into the
iWARP provider to destroy the endpoint.  Since the cmid is not locked,
its possible for the iWARP provider to pass a connection request event
to the iwcm, which will be silently dropped by the iwcm.  This causes
the iWARP provider to never free up the resources from this connection
because the assumption is the iwcm will accept or reject this connection.

The solution is to reject these connection requests.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2012-03-07 15:14:53 -08:00

1035 lines
29 KiB
C

/*
* Copyright (c) 2004, 2005 Intel Corporation. All rights reserved.
* Copyright (c) 2004 Topspin Corporation. All rights reserved.
* Copyright (c) 2004, 2005 Voltaire Corporation. All rights reserved.
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
* Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
* Copyright (c) 2005 Network Appliance, 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/dma-mapping.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <rdma/iw_cm.h>
#include <rdma/ib_addr.h>
#include "iwcm.h"
MODULE_AUTHOR("Tom Tucker");
MODULE_DESCRIPTION("iWARP CM");
MODULE_LICENSE("Dual BSD/GPL");
static struct workqueue_struct *iwcm_wq;
struct iwcm_work {
struct work_struct work;
struct iwcm_id_private *cm_id;
struct list_head list;
struct iw_cm_event event;
struct list_head free_list;
};
/*
* The following services provide a mechanism for pre-allocating iwcm_work
* elements. The design pre-allocates them based on the cm_id type:
* LISTENING IDS: Get enough elements preallocated to handle the
* listen backlog.
* ACTIVE IDS: 4: CONNECT_REPLY, ESTABLISHED, DISCONNECT, CLOSE
* PASSIVE IDS: 3: ESTABLISHED, DISCONNECT, CLOSE
*
* Allocating them in connect and listen avoids having to deal
* with allocation failures on the event upcall from the provider (which
* is called in the interrupt context).
*
* One exception is when creating the cm_id for incoming connection requests.
* There are two cases:
* 1) in the event upcall, cm_event_handler(), for a listening cm_id. If
* the backlog is exceeded, then no more connection request events will
* be processed. cm_event_handler() returns -ENOMEM in this case. Its up
* to the provider to reject the connection request.
* 2) in the connection request workqueue handler, cm_conn_req_handler().
* If work elements cannot be allocated for the new connect request cm_id,
* then IWCM will call the provider reject method. This is ok since
* cm_conn_req_handler() runs in the workqueue thread context.
*/
static struct iwcm_work *get_work(struct iwcm_id_private *cm_id_priv)
{
struct iwcm_work *work;
if (list_empty(&cm_id_priv->work_free_list))
return NULL;
work = list_entry(cm_id_priv->work_free_list.next, struct iwcm_work,
free_list);
list_del_init(&work->free_list);
return work;
}
static void put_work(struct iwcm_work *work)
{
list_add(&work->free_list, &work->cm_id->work_free_list);
}
static void dealloc_work_entries(struct iwcm_id_private *cm_id_priv)
{
struct list_head *e, *tmp;
list_for_each_safe(e, tmp, &cm_id_priv->work_free_list)
kfree(list_entry(e, struct iwcm_work, free_list));
}
static int alloc_work_entries(struct iwcm_id_private *cm_id_priv, int count)
{
struct iwcm_work *work;
BUG_ON(!list_empty(&cm_id_priv->work_free_list));
while (count--) {
work = kmalloc(sizeof(struct iwcm_work), GFP_KERNEL);
if (!work) {
dealloc_work_entries(cm_id_priv);
return -ENOMEM;
}
work->cm_id = cm_id_priv;
INIT_LIST_HEAD(&work->list);
put_work(work);
}
return 0;
}
/*
* Save private data from incoming connection requests to
* iw_cm_event, so the low level driver doesn't have to. Adjust
* the event ptr to point to the local copy.
*/
static int copy_private_data(struct iw_cm_event *event)
{
void *p;
p = kmemdup(event->private_data, event->private_data_len, GFP_ATOMIC);
if (!p)
return -ENOMEM;
event->private_data = p;
return 0;
}
static void free_cm_id(struct iwcm_id_private *cm_id_priv)
{
dealloc_work_entries(cm_id_priv);
kfree(cm_id_priv);
}
/*
* Release a reference on cm_id. If the last reference is being
* released, enable the waiting thread (in iw_destroy_cm_id) to
* get woken up, and return 1 if a thread is already waiting.
*/
static int iwcm_deref_id(struct iwcm_id_private *cm_id_priv)
{
BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
if (atomic_dec_and_test(&cm_id_priv->refcount)) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
complete(&cm_id_priv->destroy_comp);
return 1;
}
return 0;
}
static void add_ref(struct iw_cm_id *cm_id)
{
struct iwcm_id_private *cm_id_priv;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
atomic_inc(&cm_id_priv->refcount);
}
static void rem_ref(struct iw_cm_id *cm_id)
{
struct iwcm_id_private *cm_id_priv;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
if (iwcm_deref_id(cm_id_priv) &&
test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags)) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
free_cm_id(cm_id_priv);
}
}
static int cm_event_handler(struct iw_cm_id *cm_id, struct iw_cm_event *event);
struct iw_cm_id *iw_create_cm_id(struct ib_device *device,
iw_cm_handler cm_handler,
void *context)
{
struct iwcm_id_private *cm_id_priv;
cm_id_priv = kzalloc(sizeof(*cm_id_priv), GFP_KERNEL);
if (!cm_id_priv)
return ERR_PTR(-ENOMEM);
cm_id_priv->state = IW_CM_STATE_IDLE;
cm_id_priv->id.device = device;
cm_id_priv->id.cm_handler = cm_handler;
cm_id_priv->id.context = context;
cm_id_priv->id.event_handler = cm_event_handler;
cm_id_priv->id.add_ref = add_ref;
cm_id_priv->id.rem_ref = rem_ref;
spin_lock_init(&cm_id_priv->lock);
atomic_set(&cm_id_priv->refcount, 1);
init_waitqueue_head(&cm_id_priv->connect_wait);
init_completion(&cm_id_priv->destroy_comp);
INIT_LIST_HEAD(&cm_id_priv->work_list);
INIT_LIST_HEAD(&cm_id_priv->work_free_list);
return &cm_id_priv->id;
}
EXPORT_SYMBOL(iw_create_cm_id);
static int iwcm_modify_qp_err(struct ib_qp *qp)
{
struct ib_qp_attr qp_attr;
if (!qp)
return -EINVAL;
qp_attr.qp_state = IB_QPS_ERR;
return ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
}
/*
* This is really the RDMAC CLOSING state. It is most similar to the
* IB SQD QP state.
*/
static int iwcm_modify_qp_sqd(struct ib_qp *qp)
{
struct ib_qp_attr qp_attr;
BUG_ON(qp == NULL);
qp_attr.qp_state = IB_QPS_SQD;
return ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
}
/*
* CM_ID <-- CLOSING
*
* Block if a passive or active connection is currently being processed. Then
* process the event as follows:
* - If we are ESTABLISHED, move to CLOSING and modify the QP state
* based on the abrupt flag
* - If the connection is already in the CLOSING or IDLE state, the peer is
* disconnecting concurrently with us and we've already seen the
* DISCONNECT event -- ignore the request and return 0
* - Disconnect on a listening endpoint returns -EINVAL
*/
int iw_cm_disconnect(struct iw_cm_id *cm_id, int abrupt)
{
struct iwcm_id_private *cm_id_priv;
unsigned long flags;
int ret = 0;
struct ib_qp *qp = NULL;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
/* Wait if we're currently in a connect or accept downcall */
wait_event(cm_id_priv->connect_wait,
!test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));
spin_lock_irqsave(&cm_id_priv->lock, flags);
switch (cm_id_priv->state) {
case IW_CM_STATE_ESTABLISHED:
cm_id_priv->state = IW_CM_STATE_CLOSING;
/* QP could be <nul> for user-mode client */
if (cm_id_priv->qp)
qp = cm_id_priv->qp;
else
ret = -EINVAL;
break;
case IW_CM_STATE_LISTEN:
ret = -EINVAL;
break;
case IW_CM_STATE_CLOSING:
/* remote peer closed first */
case IW_CM_STATE_IDLE:
/* accept or connect returned !0 */
break;
case IW_CM_STATE_CONN_RECV:
/*
* App called disconnect before/without calling accept after
* connect_request event delivered.
*/
break;
case IW_CM_STATE_CONN_SENT:
/* Can only get here if wait above fails */
default:
BUG();
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
if (qp) {
if (abrupt)
ret = iwcm_modify_qp_err(qp);
else
ret = iwcm_modify_qp_sqd(qp);
/*
* If both sides are disconnecting the QP could
* already be in ERR or SQD states
*/
ret = 0;
}
return ret;
}
EXPORT_SYMBOL(iw_cm_disconnect);
/*
* CM_ID <-- DESTROYING
*
* Clean up all resources associated with the connection and release
* the initial reference taken by iw_create_cm_id.
*/
static void destroy_cm_id(struct iw_cm_id *cm_id)
{
struct iwcm_id_private *cm_id_priv;
unsigned long flags;
int ret;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
/*
* Wait if we're currently in a connect or accept downcall. A
* listening endpoint should never block here.
*/
wait_event(cm_id_priv->connect_wait,
!test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));
spin_lock_irqsave(&cm_id_priv->lock, flags);
switch (cm_id_priv->state) {
case IW_CM_STATE_LISTEN:
cm_id_priv->state = IW_CM_STATE_DESTROYING;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
/* destroy the listening endpoint */
ret = cm_id->device->iwcm->destroy_listen(cm_id);
spin_lock_irqsave(&cm_id_priv->lock, flags);
break;
case IW_CM_STATE_ESTABLISHED:
cm_id_priv->state = IW_CM_STATE_DESTROYING;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
/* Abrupt close of the connection */
(void)iwcm_modify_qp_err(cm_id_priv->qp);
spin_lock_irqsave(&cm_id_priv->lock, flags);
break;
case IW_CM_STATE_IDLE:
case IW_CM_STATE_CLOSING:
cm_id_priv->state = IW_CM_STATE_DESTROYING;
break;
case IW_CM_STATE_CONN_RECV:
/*
* App called destroy before/without calling accept after
* receiving connection request event notification or
* returned non zero from the event callback function.
* In either case, must tell the provider to reject.
*/
cm_id_priv->state = IW_CM_STATE_DESTROYING;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
cm_id->device->iwcm->reject(cm_id, NULL, 0);
spin_lock_irqsave(&cm_id_priv->lock, flags);
break;
case IW_CM_STATE_CONN_SENT:
case IW_CM_STATE_DESTROYING:
default:
BUG();
break;
}
if (cm_id_priv->qp) {
cm_id_priv->id.device->iwcm->rem_ref(cm_id_priv->qp);
cm_id_priv->qp = NULL;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
(void)iwcm_deref_id(cm_id_priv);
}
/*
* This function is only called by the application thread and cannot
* be called by the event thread. The function will wait for all
* references to be released on the cm_id and then kfree the cm_id
* object.
*/
void iw_destroy_cm_id(struct iw_cm_id *cm_id)
{
struct iwcm_id_private *cm_id_priv;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
BUG_ON(test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags));
destroy_cm_id(cm_id);
wait_for_completion(&cm_id_priv->destroy_comp);
free_cm_id(cm_id_priv);
}
EXPORT_SYMBOL(iw_destroy_cm_id);
/*
* CM_ID <-- LISTEN
*
* Start listening for connect requests. Generates one CONNECT_REQUEST
* event for each inbound connect request.
*/
int iw_cm_listen(struct iw_cm_id *cm_id, int backlog)
{
struct iwcm_id_private *cm_id_priv;
unsigned long flags;
int ret;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
ret = alloc_work_entries(cm_id_priv, backlog);
if (ret)
return ret;
spin_lock_irqsave(&cm_id_priv->lock, flags);
switch (cm_id_priv->state) {
case IW_CM_STATE_IDLE:
cm_id_priv->state = IW_CM_STATE_LISTEN;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id->device->iwcm->create_listen(cm_id, backlog);
if (ret)
cm_id_priv->state = IW_CM_STATE_IDLE;
spin_lock_irqsave(&cm_id_priv->lock, flags);
break;
default:
ret = -EINVAL;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
return ret;
}
EXPORT_SYMBOL(iw_cm_listen);
/*
* CM_ID <-- IDLE
*
* Rejects an inbound connection request. No events are generated.
*/
int iw_cm_reject(struct iw_cm_id *cm_id,
const void *private_data,
u8 private_data_len)
{
struct iwcm_id_private *cm_id_priv;
unsigned long flags;
int ret;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->state != IW_CM_STATE_CONN_RECV) {
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
return -EINVAL;
}
cm_id_priv->state = IW_CM_STATE_IDLE;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id->device->iwcm->reject(cm_id, private_data,
private_data_len);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
return ret;
}
EXPORT_SYMBOL(iw_cm_reject);
/*
* CM_ID <-- ESTABLISHED
*
* Accepts an inbound connection request and generates an ESTABLISHED
* event. Callers of iw_cm_disconnect and iw_destroy_cm_id will block
* until the ESTABLISHED event is received from the provider.
*/
int iw_cm_accept(struct iw_cm_id *cm_id,
struct iw_cm_conn_param *iw_param)
{
struct iwcm_id_private *cm_id_priv;
struct ib_qp *qp;
unsigned long flags;
int ret;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->state != IW_CM_STATE_CONN_RECV) {
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
return -EINVAL;
}
/* Get the ib_qp given the QPN */
qp = cm_id->device->iwcm->get_qp(cm_id->device, iw_param->qpn);
if (!qp) {
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
return -EINVAL;
}
cm_id->device->iwcm->add_ref(qp);
cm_id_priv->qp = qp;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id->device->iwcm->accept(cm_id, iw_param);
if (ret) {
/* An error on accept precludes provider events */
BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_RECV);
cm_id_priv->state = IW_CM_STATE_IDLE;
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->qp) {
cm_id->device->iwcm->rem_ref(qp);
cm_id_priv->qp = NULL;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
}
return ret;
}
EXPORT_SYMBOL(iw_cm_accept);
/*
* Active Side: CM_ID <-- CONN_SENT
*
* If successful, results in the generation of a CONNECT_REPLY
* event. iw_cm_disconnect and iw_cm_destroy will block until the
* CONNECT_REPLY event is received from the provider.
*/
int iw_cm_connect(struct iw_cm_id *cm_id, struct iw_cm_conn_param *iw_param)
{
struct iwcm_id_private *cm_id_priv;
int ret;
unsigned long flags;
struct ib_qp *qp;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
ret = alloc_work_entries(cm_id_priv, 4);
if (ret)
return ret;
set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->state != IW_CM_STATE_IDLE) {
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
return -EINVAL;
}
/* Get the ib_qp given the QPN */
qp = cm_id->device->iwcm->get_qp(cm_id->device, iw_param->qpn);
if (!qp) {
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
return -EINVAL;
}
cm_id->device->iwcm->add_ref(qp);
cm_id_priv->qp = qp;
cm_id_priv->state = IW_CM_STATE_CONN_SENT;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id->device->iwcm->connect(cm_id, iw_param);
if (ret) {
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->qp) {
cm_id->device->iwcm->rem_ref(qp);
cm_id_priv->qp = NULL;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_SENT);
cm_id_priv->state = IW_CM_STATE_IDLE;
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
wake_up_all(&cm_id_priv->connect_wait);
}
return ret;
}
EXPORT_SYMBOL(iw_cm_connect);
/*
* Passive Side: new CM_ID <-- CONN_RECV
*
* Handles an inbound connect request. The function creates a new
* iw_cm_id to represent the new connection and inherits the client
* callback function and other attributes from the listening parent.
*
* The work item contains a pointer to the listen_cm_id and the event. The
* listen_cm_id contains the client cm_handler, context and
* device. These are copied when the device is cloned. The event
* contains the new four tuple.
*
* An error on the child should not affect the parent, so this
* function does not return a value.
*/
static void cm_conn_req_handler(struct iwcm_id_private *listen_id_priv,
struct iw_cm_event *iw_event)
{
unsigned long flags;
struct iw_cm_id *cm_id;
struct iwcm_id_private *cm_id_priv;
int ret;
/*
* The provider should never generate a connection request
* event with a bad status.
*/
BUG_ON(iw_event->status);
cm_id = iw_create_cm_id(listen_id_priv->id.device,
listen_id_priv->id.cm_handler,
listen_id_priv->id.context);
/* If the cm_id could not be created, ignore the request */
if (IS_ERR(cm_id))
goto out;
cm_id->provider_data = iw_event->provider_data;
cm_id->local_addr = iw_event->local_addr;
cm_id->remote_addr = iw_event->remote_addr;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
cm_id_priv->state = IW_CM_STATE_CONN_RECV;
/*
* We could be destroying the listening id. If so, ignore this
* upcall.
*/
spin_lock_irqsave(&listen_id_priv->lock, flags);
if (listen_id_priv->state != IW_CM_STATE_LISTEN) {
spin_unlock_irqrestore(&listen_id_priv->lock, flags);
iw_cm_reject(cm_id, NULL, 0);
iw_destroy_cm_id(cm_id);
goto out;
}
spin_unlock_irqrestore(&listen_id_priv->lock, flags);
ret = alloc_work_entries(cm_id_priv, 3);
if (ret) {
iw_cm_reject(cm_id, NULL, 0);
iw_destroy_cm_id(cm_id);
goto out;
}
/* Call the client CM handler */
ret = cm_id->cm_handler(cm_id, iw_event);
if (ret) {
iw_cm_reject(cm_id, NULL, 0);
set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
destroy_cm_id(cm_id);
if (atomic_read(&cm_id_priv->refcount)==0)
free_cm_id(cm_id_priv);
}
out:
if (iw_event->private_data_len)
kfree(iw_event->private_data);
}
/*
* Passive Side: CM_ID <-- ESTABLISHED
*
* The provider generated an ESTABLISHED event which means that
* the MPA negotion has completed successfully and we are now in MPA
* FPDU mode.
*
* This event can only be received in the CONN_RECV state. If the
* remote peer closed, the ESTABLISHED event would be received followed
* by the CLOSE event. If the app closes, it will block until we wake
* it up after processing this event.
*/
static int cm_conn_est_handler(struct iwcm_id_private *cm_id_priv,
struct iw_cm_event *iw_event)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&cm_id_priv->lock, flags);
/*
* We clear the CONNECT_WAIT bit here to allow the callback
* function to call iw_cm_disconnect. Calling iw_destroy_cm_id
* from a callback handler is not allowed.
*/
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_RECV);
cm_id_priv->state = IW_CM_STATE_ESTABLISHED;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
wake_up_all(&cm_id_priv->connect_wait);
return ret;
}
/*
* Active Side: CM_ID <-- ESTABLISHED
*
* The app has called connect and is waiting for the established event to
* post it's requests to the server. This event will wake up anyone
* blocked in iw_cm_disconnect or iw_destroy_id.
*/
static int cm_conn_rep_handler(struct iwcm_id_private *cm_id_priv,
struct iw_cm_event *iw_event)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&cm_id_priv->lock, flags);
/*
* Clear the connect wait bit so a callback function calling
* iw_cm_disconnect will not wait and deadlock this thread
*/
clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_SENT);
if (iw_event->status == 0) {
cm_id_priv->id.local_addr = iw_event->local_addr;
cm_id_priv->id.remote_addr = iw_event->remote_addr;
cm_id_priv->state = IW_CM_STATE_ESTABLISHED;
} else {
/* REJECTED or RESET */
cm_id_priv->id.device->iwcm->rem_ref(cm_id_priv->qp);
cm_id_priv->qp = NULL;
cm_id_priv->state = IW_CM_STATE_IDLE;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
if (iw_event->private_data_len)
kfree(iw_event->private_data);
/* Wake up waiters on connect complete */
wake_up_all(&cm_id_priv->connect_wait);
return ret;
}
/*
* CM_ID <-- CLOSING
*
* If in the ESTABLISHED state, move to CLOSING.
*/
static void cm_disconnect_handler(struct iwcm_id_private *cm_id_priv,
struct iw_cm_event *iw_event)
{
unsigned long flags;
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->state == IW_CM_STATE_ESTABLISHED)
cm_id_priv->state = IW_CM_STATE_CLOSING;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
}
/*
* CM_ID <-- IDLE
*
* If in the ESTBLISHED or CLOSING states, the QP will have have been
* moved by the provider to the ERR state. Disassociate the CM_ID from
* the QP, move to IDLE, and remove the 'connected' reference.
*
* If in some other state, the cm_id was destroyed asynchronously.
* This is the last reference that will result in waking up
* the app thread blocked in iw_destroy_cm_id.
*/
static int cm_close_handler(struct iwcm_id_private *cm_id_priv,
struct iw_cm_event *iw_event)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&cm_id_priv->lock, flags);
if (cm_id_priv->qp) {
cm_id_priv->id.device->iwcm->rem_ref(cm_id_priv->qp);
cm_id_priv->qp = NULL;
}
switch (cm_id_priv->state) {
case IW_CM_STATE_ESTABLISHED:
case IW_CM_STATE_CLOSING:
cm_id_priv->state = IW_CM_STATE_IDLE;
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
spin_lock_irqsave(&cm_id_priv->lock, flags);
break;
case IW_CM_STATE_DESTROYING:
break;
default:
BUG();
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
return ret;
}
static int process_event(struct iwcm_id_private *cm_id_priv,
struct iw_cm_event *iw_event)
{
int ret = 0;
switch (iw_event->event) {
case IW_CM_EVENT_CONNECT_REQUEST:
cm_conn_req_handler(cm_id_priv, iw_event);
break;
case IW_CM_EVENT_CONNECT_REPLY:
ret = cm_conn_rep_handler(cm_id_priv, iw_event);
break;
case IW_CM_EVENT_ESTABLISHED:
ret = cm_conn_est_handler(cm_id_priv, iw_event);
break;
case IW_CM_EVENT_DISCONNECT:
cm_disconnect_handler(cm_id_priv, iw_event);
break;
case IW_CM_EVENT_CLOSE:
ret = cm_close_handler(cm_id_priv, iw_event);
break;
default:
BUG();
}
return ret;
}
/*
* Process events on the work_list for the cm_id. If the callback
* function requests that the cm_id be deleted, a flag is set in the
* cm_id flags to indicate that when the last reference is
* removed, the cm_id is to be destroyed. This is necessary to
* distinguish between an object that will be destroyed by the app
* thread asleep on the destroy_comp list vs. an object destroyed
* here synchronously when the last reference is removed.
*/
static void cm_work_handler(struct work_struct *_work)
{
struct iwcm_work *work = container_of(_work, struct iwcm_work, work);
struct iw_cm_event levent;
struct iwcm_id_private *cm_id_priv = work->cm_id;
unsigned long flags;
int empty;
int ret = 0;
int destroy_id;
spin_lock_irqsave(&cm_id_priv->lock, flags);
empty = list_empty(&cm_id_priv->work_list);
while (!empty) {
work = list_entry(cm_id_priv->work_list.next,
struct iwcm_work, list);
list_del_init(&work->list);
empty = list_empty(&cm_id_priv->work_list);
levent = work->event;
put_work(work);
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
ret = process_event(cm_id_priv, &levent);
if (ret) {
set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
destroy_cm_id(&cm_id_priv->id);
}
BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
destroy_id = test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
if (iwcm_deref_id(cm_id_priv)) {
if (destroy_id) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
free_cm_id(cm_id_priv);
}
return;
}
spin_lock_irqsave(&cm_id_priv->lock, flags);
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
}
/*
* This function is called on interrupt context. Schedule events on
* the iwcm_wq thread to allow callback functions to downcall into
* the CM and/or block. Events are queued to a per-CM_ID
* work_list. If this is the first event on the work_list, the work
* element is also queued on the iwcm_wq thread.
*
* Each event holds a reference on the cm_id. Until the last posted
* event has been delivered and processed, the cm_id cannot be
* deleted.
*
* Returns:
* 0 - the event was handled.
* -ENOMEM - the event was not handled due to lack of resources.
*/
static int cm_event_handler(struct iw_cm_id *cm_id,
struct iw_cm_event *iw_event)
{
struct iwcm_work *work;
struct iwcm_id_private *cm_id_priv;
unsigned long flags;
int ret = 0;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
spin_lock_irqsave(&cm_id_priv->lock, flags);
work = get_work(cm_id_priv);
if (!work) {
ret = -ENOMEM;
goto out;
}
INIT_WORK(&work->work, cm_work_handler);
work->cm_id = cm_id_priv;
work->event = *iw_event;
if ((work->event.event == IW_CM_EVENT_CONNECT_REQUEST ||
work->event.event == IW_CM_EVENT_CONNECT_REPLY) &&
work->event.private_data_len) {
ret = copy_private_data(&work->event);
if (ret) {
put_work(work);
goto out;
}
}
atomic_inc(&cm_id_priv->refcount);
if (list_empty(&cm_id_priv->work_list)) {
list_add_tail(&work->list, &cm_id_priv->work_list);
queue_work(iwcm_wq, &work->work);
} else
list_add_tail(&work->list, &cm_id_priv->work_list);
out:
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
return ret;
}
static int iwcm_init_qp_init_attr(struct iwcm_id_private *cm_id_priv,
struct ib_qp_attr *qp_attr,
int *qp_attr_mask)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&cm_id_priv->lock, flags);
switch (cm_id_priv->state) {
case IW_CM_STATE_IDLE:
case IW_CM_STATE_CONN_SENT:
case IW_CM_STATE_CONN_RECV:
case IW_CM_STATE_ESTABLISHED:
*qp_attr_mask = IB_QP_STATE | IB_QP_ACCESS_FLAGS;
qp_attr->qp_access_flags = IB_ACCESS_REMOTE_WRITE|
IB_ACCESS_REMOTE_READ;
ret = 0;
break;
default:
ret = -EINVAL;
break;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
return ret;
}
static int iwcm_init_qp_rts_attr(struct iwcm_id_private *cm_id_priv,
struct ib_qp_attr *qp_attr,
int *qp_attr_mask)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&cm_id_priv->lock, flags);
switch (cm_id_priv->state) {
case IW_CM_STATE_IDLE:
case IW_CM_STATE_CONN_SENT:
case IW_CM_STATE_CONN_RECV:
case IW_CM_STATE_ESTABLISHED:
*qp_attr_mask = 0;
ret = 0;
break;
default:
ret = -EINVAL;
break;
}
spin_unlock_irqrestore(&cm_id_priv->lock, flags);
return ret;
}
int iw_cm_init_qp_attr(struct iw_cm_id *cm_id,
struct ib_qp_attr *qp_attr,
int *qp_attr_mask)
{
struct iwcm_id_private *cm_id_priv;
int ret;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
switch (qp_attr->qp_state) {
case IB_QPS_INIT:
case IB_QPS_RTR:
ret = iwcm_init_qp_init_attr(cm_id_priv,
qp_attr, qp_attr_mask);
break;
case IB_QPS_RTS:
ret = iwcm_init_qp_rts_attr(cm_id_priv,
qp_attr, qp_attr_mask);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
EXPORT_SYMBOL(iw_cm_init_qp_attr);
static int __init iw_cm_init(void)
{
iwcm_wq = create_singlethread_workqueue("iw_cm_wq");
if (!iwcm_wq)
return -ENOMEM;
return 0;
}
static void __exit iw_cm_cleanup(void)
{
destroy_workqueue(iwcm_wq);
}
module_init(iw_cm_init);
module_exit(iw_cm_cleanup);