include/linux/sunrpc/svc_rdma.h

/*
 * Copyright (c) 2005-2006 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>
 */

#ifndef SVC_RDMA_H
#define SVC_RDMA_H
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#define SVCRDMA_DEBUG

/* RPC/RDMA parameters and stats */
extern unsigned int svcrdma_ord;
extern unsigned int svcrdma_max_requests;
extern unsigned int svcrdma_max_req_size;

extern atomic_t rdma_stat_recv;
extern atomic_t rdma_stat_read;
extern atomic_t rdma_stat_write;
extern atomic_t rdma_stat_sq_starve;
extern atomic_t rdma_stat_rq_starve;
extern atomic_t rdma_stat_rq_poll;
extern atomic_t rdma_stat_rq_prod;
extern atomic_t rdma_stat_sq_poll;
extern atomic_t rdma_stat_sq_prod;

#define RPCRDMA_VERSION 1

/*
 * Contexts are built when an RDMA request is created and are a
 * record of the resources that can be recovered when the request
 * completes.
 */
struct svc_rdma_op_ctxt {
	struct svc_rdma_op_ctxt *read_hdr;
	int hdr_count;
	struct xdr_buf arg;
	struct list_head dto_q;
	enum ib_wr_opcode wr_op;
	enum ib_wc_status wc_status;
	u32 byte_len;
	struct svcxprt_rdma *xprt;
	unsigned long flags;
	enum dma_data_direction direction;
	int count;
	struct ib_sge sge[RPCSVC_MAXPAGES];
	struct page *pages[RPCSVC_MAXPAGES];
};

/*
 * NFS_ requests are mapped on the client side by the chunk lists in
 * the RPCRDMA header. During the fetching of the RPC from the client
 * and the writing of the reply to the client, the memory in the
 * client and the memory in the server must be mapped as contiguous
 * vaddr/len for access by the hardware. These data strucures keep
 * these mappings.
 *
 * For an RDMA_WRITE, the 'sge' maps the RPC REPLY. For RDMA_READ, the
 * 'sge' in the svc_rdma_req_map maps the server side RPC reply and the
 * 'ch' field maps the read-list of the RPCRDMA header to the 'sge'
 * mapping of the reply.
 */
struct svc_rdma_chunk_sge {
	int start;		/* sge no for this chunk */
	int count;		/* sge count for this chunk */
};
struct svc_rdma_req_map {
	unsigned long count;
	union {
		struct kvec sge[RPCSVC_MAXPAGES];
		struct svc_rdma_chunk_sge ch[RPCSVC_MAXPAGES];
	};
};

#define RDMACTXT_F_LAST_CTXT	2

struct svcxprt_rdma {
	struct svc_xprt      sc_xprt;		/* SVC transport structure */
	struct rdma_cm_id    *sc_cm_id;		/* RDMA connection id */
	struct list_head     sc_accept_q;	/* Conn. waiting accept */
	int		     sc_ord;		/* RDMA read limit */
	int                  sc_max_sge;

	int                  sc_sq_depth;	/* Depth of SQ */
	atomic_t             sc_sq_count;	/* Number of SQ WR on queue */

	int                  sc_max_requests;	/* Depth of RQ */
	int                  sc_max_req_size;	/* Size of each RQ WR buf */

	struct ib_pd         *sc_pd;

	atomic_t	     sc_dma_used;
	atomic_t	     sc_ctxt_used;
	struct list_head     sc_rq_dto_q;
	spinlock_t	     sc_rq_dto_lock;
	struct ib_qp         *sc_qp;
	struct ib_cq         *sc_rq_cq;
	struct ib_cq         *sc_sq_cq;
	struct ib_mr         *sc_phys_mr;	/* MR for server memory */

	spinlock_t	     sc_lock;		/* transport lock */

	wait_queue_head_t    sc_send_wait;	/* SQ exhaustion waitlist */
	unsigned long	     sc_flags;
	struct list_head     sc_dto_q;		/* DTO tasklet I/O pending Q */
	struct list_head     sc_read_complete_q;
	spinlock_t           sc_read_complete_lock;
	struct work_struct   sc_work;
};
/* sc_flags */
#define RDMAXPRT_RQ_PENDING	1
#define RDMAXPRT_SQ_PENDING	2
#define RDMAXPRT_CONN_PENDING	3

#define RPCRDMA_LISTEN_BACKLOG  10
/* The default ORD value is based on two outstanding full-size writes with a
 * page size of 4k, or 32k * 2 ops / 4k = 16 outstanding RDMA_READ.  */
#define RPCRDMA_ORD             (64/4)
#define RPCRDMA_SQ_DEPTH_MULT   8
#define RPCRDMA_MAX_THREADS     16
#define RPCRDMA_MAX_REQUESTS    16
#define RPCRDMA_MAX_REQ_SIZE    4096

/* svc_rdma_marshal.c */
extern void svc_rdma_rcl_chunk_counts(struct rpcrdma_read_chunk *,
				      int *, int *);
extern int svc_rdma_xdr_decode_req(struct rpcrdma_msg **, struct svc_rqst *);
extern int svc_rdma_xdr_decode_deferred_req(struct svc_rqst *);
extern int svc_rdma_xdr_encode_error(struct svcxprt_rdma *,
				     struct rpcrdma_msg *,
				     enum rpcrdma_errcode, u32 *);
extern void svc_rdma_xdr_encode_write_list(struct rpcrdma_msg *, int);
extern void svc_rdma_xdr_encode_reply_array(struct rpcrdma_write_array *, int);
extern void svc_rdma_xdr_encode_array_chunk(struct rpcrdma_write_array *, int,
					    u32, u64, u32);
extern void svc_rdma_xdr_encode_reply_header(struct svcxprt_rdma *,
					     struct rpcrdma_msg *,
					     struct rpcrdma_msg *,
					     enum rpcrdma_proc);
extern int svc_rdma_xdr_get_reply_hdr_len(struct rpcrdma_msg *);

/* svc_rdma_recvfrom.c */
extern int svc_rdma_recvfrom(struct svc_rqst *);

/* svc_rdma_sendto.c */
extern int svc_rdma_sendto(struct svc_rqst *);

/* svc_rdma_transport.c */
extern int svc_rdma_send(struct svcxprt_rdma *, struct ib_send_wr *);
extern void svc_rdma_send_error(struct svcxprt_rdma *, struct rpcrdma_msg *,
				enum rpcrdma_errcode);
struct page *svc_rdma_get_page(void);
extern int svc_rdma_post_recv(struct svcxprt_rdma *);
extern int svc_rdma_create_listen(struct svc_serv *, int, struct sockaddr *);
extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
extern void svc_sq_reap(struct svcxprt_rdma *);
extern void svc_rq_reap(struct svcxprt_rdma *);
extern struct svc_xprt_class svc_rdma_class;
extern void svc_rdma_prep_reply_hdr(struct svc_rqst *);

/* svc_rdma.c */
extern int svc_rdma_init(void);
extern void svc_rdma_cleanup(void);

/*
 * Returns the address of the first read chunk or <nul> if no read chunk is
 * present
 */
static inline struct rpcrdma_read_chunk *
svc_rdma_get_read_chunk(struct rpcrdma_msg *rmsgp)
{
	struct rpcrdma_read_chunk *ch =
		(struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];

	if (ch->rc_discrim == 0)
		return NULL;

	return ch;
}

/*
 * Returns the address of the first read write array element or <nul> if no
 * write array list is present
 */
static inline struct rpcrdma_write_array *
svc_rdma_get_write_array(struct rpcrdma_msg *rmsgp)
{
	if (rmsgp->rm_body.rm_chunks[0] != 0
	    || rmsgp->rm_body.rm_chunks[1] == 0)
		return NULL;

	return (struct rpcrdma_write_array *)&rmsgp->rm_body.rm_chunks[1];
}

/*
 * Returns the address of the first reply array element or <nul> if no
 * reply array is present
 */
static inline struct rpcrdma_write_array *
svc_rdma_get_reply_array(struct rpcrdma_msg *rmsgp)
{
	struct rpcrdma_read_chunk *rch;
	struct rpcrdma_write_array *wr_ary;
	struct rpcrdma_write_array *rp_ary;

	/* XXX: Need to fix when reply list may occur with read-list and/or
	 * write list */
	if (rmsgp->rm_body.rm_chunks[0] != 0 ||
	    rmsgp->rm_body.rm_chunks[1] != 0)
		return NULL;

	rch = svc_rdma_get_read_chunk(rmsgp);
	if (rch) {
		while (rch->rc_discrim)
			rch++;

		/* The reply list follows an empty write array located
		 * at 'rc_position' here. The reply array is at rc_target.
		 */
		rp_ary = (struct rpcrdma_write_array *)&rch->rc_target;

		goto found_it;
	}

	wr_ary = svc_rdma_get_write_array(rmsgp);
	if (wr_ary) {
		rp_ary = (struct rpcrdma_write_array *)
			&wr_ary->
			wc_array[wr_ary->wc_nchunks].wc_target.rs_length;

		goto found_it;
	}

	/* No read list, no write list */
	rp_ary = (struct rpcrdma_write_array *)
		&rmsgp->rm_body.rm_chunks[2];

 found_it:
	if (rp_ary->wc_discrim == 0)
		return NULL;

	return rp_ary;
}
#endif