path: root/net/sunrpc/xprtrdma/svc_rdma_transport.c

/*
 * Copyright (c) 2005-2007 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 BSD-type
 * 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.
 *
 *      Neither the name of the Network Appliance, Inc. 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.
 *
 * Author: Tom Tucker <tom@opengridcomputing.com>
 */

#include <linux/sunrpc/svc_xprt.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/spinlock.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <linux/sunrpc/svc_rdma.h>

#define RPCDBG_FACILITY	RPCDBG_SVCXPRT

static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
					struct sockaddr *sa, int salen,
					int flags);
static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
static void svc_rdma_release_rqst(struct svc_rqst *);
static void dto_tasklet_func(unsigned long data);
static void svc_rdma_detach(struct svc_xprt *xprt);
static void svc_rdma_free(struct svc_xprt *xprt);
static int svc_rdma_has_wspace(struct svc_xprt *xprt);
static void rq_cq_reap(struct svcxprt_rdma *xprt);
static void sq_cq_reap(struct svcxprt_rdma *xprt);

DECLARE_TASKLET(dto_tasklet, dto_tasklet_func, 0UL);
static DEFINE_SPINLOCK(dto_lock);
static LIST_HEAD(dto_xprt_q);

static struct svc_xprt_ops svc_rdma_ops = {
	.xpo_create = svc_rdma_create,
	.xpo_recvfrom = svc_rdma_recvfrom,
	.xpo_sendto = svc_rdma_sendto,
	.xpo_release_rqst = svc_rdma_release_rqst,
	.xpo_detach = svc_rdma_detach,
	.xpo_free = svc_rdma_free,
	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
	.xpo_has_wspace = svc_rdma_has_wspace,
	.xpo_accept = svc_rdma_accept,
};

struct svc_xprt_class svc_rdma_class = {
	.xcl_name = "rdma",
	.xcl_owner = THIS_MODULE,
	.xcl_ops = &svc_rdma_ops,
	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
};

static int rdma_bump_context_cache(struct svcxprt_rdma *xprt)
{
	int target;
	int at_least_one = 0;
	struct svc_rdma_op_ctxt *ctxt;

	target = min(xprt->sc_ctxt_cnt + xprt->sc_ctxt_bump,
		     xprt->sc_ctxt_max);

	spin_lock_bh(&xprt->sc_ctxt_lock);
	while (xprt->sc_ctxt_cnt < target) {
		xprt->sc_ctxt_cnt++;
		spin_unlock_bh(&xprt->sc_ctxt_lock);

		ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);

		spin_lock_bh(&xprt->sc_ctxt_lock);
		if (ctxt) {
			at_least_one = 1;
			ctxt->next = xprt->sc_ctxt_head;
			xprt->sc_ctxt_head = ctxt;
		} else {
			/* kmalloc failed...give up for now */
			xprt->sc_ctxt_cnt--;
			break;
		}
	}
	spin_unlock_bh(&xprt->sc_ctxt_lock);
	dprintk("svcrdma: sc_ctxt_max=%d, sc_ctxt_cnt=%d\n",
		xprt->sc_ctxt_max, xprt->sc_ctxt_cnt);
	return at_least_one;
}

struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
{
	struct svc_rdma_op_ctxt *ctxt;

	while (1) {
		spin_lock_bh(&xprt->sc_ctxt_lock);
		if (unlikely(xprt->sc_ctxt_head == NULL)) {
			/* Try to bump my cache. */
			spin_unlock_bh(&xprt->sc_ctxt_lock);

			if (