/*
* Copyright (c) 2005 Ammasso, Inc. All rights reserved.
* Copyright (c) 2005 Open Grid Computing, 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/slab.h>
#include <linux/spinlock.h>
#include "c2_vq.h"
#include "c2_provider.h"
/*
* Verbs Request Objects:
*
* VQ Request Objects are allocated by the kernel verbs handlers.
* They contain a wait object, a refcnt, an atomic bool indicating that the
* adapter has replied, and a copy of the verb reply work request.
* A pointer to the VQ Request Object is passed down in the context
* field of the work request message, and reflected back by the adapter
* in the verbs reply message. The function handle_vq() in the interrupt
* path will use this pointer to:
* 1) append a copy of the verbs reply message
* 2) mark that the reply is ready
* 3) wake up the kernel verbs handler blocked awaiting the reply.
*
*
* The kernel verbs handlers do a "get" to put a 2nd reference on the
* VQ Request object. If the kernel verbs handler exits before the adapter
* can respond, this extra reference will keep the VQ Request object around
* until the adapter's reply can be processed. The reason we need this is
* because a pointer to this object is stuffed into the context field of
* the verbs work request message, and reflected back in the reply message.
* It is used in the interrupt handler (handle_vq()) to wake up the appropriate
* kernel verb handler that is blocked awaiting the verb reply.
* So handle_vq() will do a "put" on the object when it's done accessing it.
* NOTE: If we guarantee that the kernel verb handler will never bail before
* getting the reply, then we don't need these refcnts.
*
*
* VQ Request objects are freed by the kernel verbs handlers only
* after the verb has been processed, or when the adapter fails and
* does not reply.
*
*
* Verbs Reply Buffers:
*
* VQ Reply bufs are local host memory copies of a
* outstanding Verb Request reply
* message. The are always allocated by the kernel verbs handlers, and _may_ be
* freed by either the kernel verbs handler -or- the interrupt handler. The
* kernel verbs handler _must_ free the repbuf, then free the vq request object
* in that order.
*/
int vq_init(struct c2_dev *c2dev)
{
sprintf(c2dev->vq_cache_name, "c2-vq:dev%c",
(char) ('0' + c2dev->devnum));
c2dev->host_msg_cache =
kmem_cache_create(c2dev->vq_cache_name, c2dev->rep_vq.msg_size, 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (c2dev->host_msg_cache == NULL) {
return -ENOMEM;
}
return 0;
}
void vq_term(struct c2_dev *c2dev)
{
kmem_cache_destroy(c2dev->host_msg_cache);
}
/* vq_req_alloc - allocate a VQ Request Object and initialize it.
* The refcnt is set to 1.
*/
struct c2_vq_req *vq_req_alloc(struct c2_dev *c2dev)
{
struct c2_vq_req *r;
r = kmalloc(sizeof(struct c2_vq_req), GFP_KERNEL);
if (r) {
init_waitqueue_head(&r->wait_object);
r->reply_msg = (u64) NULL;
r->event = 0;
r->cm_id = NULL;
r->qp = NULL;
atomic_set(&r->refcnt, 1);
atomic_set(&r->reply_ready, 0);
}
return r;
}
/* vq_req_free - free the VQ Request Object. It is assumed the verbs handler
* has already free the VQ Reply Buffer if it existed.
*/
void vq_req_free(struct c2_dev *c2dev, struct c2_vq_req *r)
{
r->reply_msg = (u64) NULL;
if (atomic_dec_and_test(&r->refcnt)) {
kfree(r);
}
}
/* vq_req_get - reference a VQ Request Object. Done
* only in the kernel verbs handlers.
*/
void vq_req_get(struct c2_dev *c2dev, struct c2_vq_req *r)
{
atomic_inc(&r->refcnt);
}
/* vq_req_put - dereference and potentially free a VQ Request Object.
*
* This is only called by handle_vq() on the
* interrupt when it is done processing
* a verb reply message. If the associated
* kernel verbs handler has already bailed,
* then this put will actually free the VQ
* Request object _and_ the VQ Reply Buffer
* if it exists.
*/
void vq_req_put(struct c2_dev *c2dev, struct c2_vq_req *r)
{
if (atomic_dec_and_test(&r->refcnt)) {
if (r->reply_msg != (u64) NULL)
vq_repbuf_free(c2dev,
(void *) (unsigned long) r->reply_msg);
kfree(r);
}
}
/*
* vq_repbuf_alloc - allocate a VQ Reply Buffer.
*/
void *vq_repbuf_alloc(struct c2_dev *c2dev)
{
return kmem_cache_alloc(c2dev->host_msg_cache, SLAB_ATOMIC);
}
/*
* vq_send_wr - post a verbs request message to the Verbs Request Queue.
* If a message is not available in the MQ, then block until one is available.
* NOTE: handle_mq() on the interrupt context will wake up threads blocked here.
* When the adapter drains the Verbs Request Queue,
* it inserts MQ index 0 in to the
* adapter->host activity fifo and interrupts the host.
*/
int vq_send_wr(struct c2_dev *c2dev, union c2wr *wr)
{
void *msg;
wait_queue_t __wait;
/*
* grab adapter vq lock
*/
spin_lock(&c2dev->vqlock);
/*
* allocate msg
*/
msg = c2_mq_alloc(&c2dev->req_vq);
/*
* If we cannot get a msg, then we'll wait
* When a messages are available, the int handler will wake_up()
* any waiters.
*/
while (msg == NULL) {
pr_debug("%s:%d no available msg in VQ, waiting...\n",
__FUNCTION__, __LINE__);
init_waitqueue_entry(&__wait, current);
add_wait_queue(&c2dev->req_vq_wo, &__wait);
spin_unlock(&c2dev->vqlock);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (!c2_mq_full(&c2dev->req_vq)) {
break;
}
if (!signal_pending(current)) {
schedule_timeout(1 * HZ); /* 1 second... */
continue;
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&c2dev->req_vq_wo, &__wait);
return -EINTR;
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&c2dev->req_vq_wo, &__wait);
spin_lock(&c2dev->vqlock);
msg = c2_mq_alloc(&c2dev->req_vq);
}
/*
* copy wr into adapter msg
*/
memcpy(msg, wr, c2dev->req_vq.msg_size);
/*
* post msg
*/
c2_mq_produce(&c2dev->req_vq);
/*
* release adapter vq lock
*/
spin_unlock(&c2dev->vqlock);
return 0;
}
/*
* vq_wait_for_reply - block until the adapter posts a Verb Reply Message.
*/
int vq_wait_for_reply(struct c2_dev *c2dev, struct c2_vq_req *req)
{
if (!wait_event_timeout(req->wait_object,
atomic_read(&req->reply_ready),
60*HZ))
return -ETIMEDOUT;
return 0;
}
/*
* vq_repbuf_free - Free a Verbs Reply Buffer.
*/
void vq_repbuf_free(struct c2_dev *c2dev, void *reply)
{
kmem_cache_free(c2dev->host_msg_cache, reply);
}
