--- /dev/null
+/*
+ * 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, GFP_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);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff