include/linux/sunrpc/svc_rdma.h - kernel/msm-4.19 - Gitiles

 /*
  * 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;

 /*
  * 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;
 	struct svc_rdma_fastreg_mr *frmr;
 	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;
 	u32 position;
 	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_fastreg_mr {
 	struct ib_mr *mr;
 	void *kva;
 	struct ib_fast_reg_page_list *page_list;
 	int page_list_len;
 	unsigned long access_flags;
 	unsigned long map_len;
 	enum dma_data_direction direction;
 	struct list_head frmr_list;
 };
 struct svc_rdma_req_map {
 	unsigned long count;
 	union {
 		struct kvec sge[RPCSVC_MAXPAGES];
 		struct svc_rdma_chunk_sge ch[RPCSVC_MAXPAGES];
 		unsigned long lkey[RPCSVC_MAXPAGES];
 	};
 };
 #define RDMACTXT_F_LAST_CTXT	2

 #define	SVCRDMA_DEVCAP_FAST_REG		1	/* fast mr registration */
 #define	SVCRDMA_DEVCAP_READ_W_INV	2	/* read w/ invalidate */

 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 */
 	int		     (*sc_reader)(struct svcxprt_rdma *,
 					  struct svc_rqst *,
 					  struct svc_rdma_op_ctxt *,
 					  int *, u32 *, u32, u32, u64, bool);
 	u32		     sc_dev_caps;	/* distilled device caps */
 	u32		     sc_dma_lkey;	/* local dma key */
 	unsigned int	     sc_frmr_pg_list_len;
 	struct list_head     sc_frmr_q;
 	spinlock_t	     sc_frmr_q_lock;

 	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;
 	struct work_struct   sc_work;
 };
 /* sc_flags */
 #define RDMAXPRT_RQ_PENDING	1
 #define RDMAXPRT_SQ_PENDING	2
 #define RDMAXPRT_CONN_PENDING	3

 #define RPCRDMA_MAX_SVC_SEGS	(64)	/* server max scatter/gather */
 #if RPCSVC_MAXPAYLOAD < (RPCRDMA_MAX_SVC_SEGS << PAGE_SHIFT)
 #define RPCRDMA_MAXPAYLOAD	RPCSVC_MAXPAYLOAD
 #else
 #define RPCRDMA_MAXPAYLOAD	(RPCRDMA_MAX_SVC_SEGS << PAGE_SHIFT)
 #endif

 #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_REQUESTS    32
 #define RPCRDMA_MAX_REQ_SIZE    4096

 /* svc_rdma_marshal.c */
 extern int svc_rdma_xdr_decode_req(struct rpcrdma_msg **, struct svc_rqst *);
 extern int svc_rdma_xdr_encode_error(struct svcxprt_rdma *,
 				     struct rpcrdma_msg *,
 				     enum rpcrdma_errcode, __be32 *);
 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,
 					    __be32, __be64, 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 *);
 extern int rdma_read_chunk_lcl(struct svcxprt_rdma *, struct svc_rqst *,
 			       struct svc_rdma_op_ctxt *, int *, u32 *,
 			       u32, u32, u64, bool);
 extern int rdma_read_chunk_frmr(struct svcxprt_rdma *, struct svc_rqst *,
 				struct svc_rdma_op_ctxt *, int *, u32 *,
 				u32, u32, u64, bool);

 /* 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);
 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 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt);
 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 int svc_rdma_fastreg(struct svcxprt_rdma *, struct svc_rdma_fastreg_mr *);
 extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
 extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
 			      struct svc_rdma_fastreg_mr *);
 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[ntohl(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
	/*
	* 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;

	/*
	* 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;
	struct svc_rdma_fastreg_mr *frmr;
	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;
	u32 position;
	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_fastreg_mr {
	struct ib_mr *mr;
	void *kva;
	struct ib_fast_reg_page_list *page_list;
	int page_list_len;
	unsigned long access_flags;
	unsigned long map_len;
	enum dma_data_direction direction;
	struct list_head frmr_list;
	};
	struct svc_rdma_req_map {
	unsigned long count;
	union {
	struct kvec sge[RPCSVC_MAXPAGES];
	struct svc_rdma_chunk_sge ch[RPCSVC_MAXPAGES];
	unsigned long lkey[RPCSVC_MAXPAGES];
	};
	};
	#define RDMACTXT_F_LAST_CTXT 2

	#define SVCRDMA_DEVCAP_FAST_REG 1 /* fast mr registration */
	#define SVCRDMA_DEVCAP_READ_W_INV 2 /* read w/ invalidate */

	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 */
	int (sc_reader)(struct svcxprt_rdma ,
	struct svc_rqst *,
	struct svc_rdma_op_ctxt *,
	int , u32 , u32, u32, u64, bool);
	u32 sc_dev_caps; /* distilled device caps */
	u32 sc_dma_lkey; /* local dma key */
	unsigned int sc_frmr_pg_list_len;
	struct list_head sc_frmr_q;
	spinlock_t sc_frmr_q_lock;

	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;
	struct work_struct sc_work;
	};
	/* sc_flags */
	#define RDMAXPRT_RQ_PENDING 1
	#define RDMAXPRT_SQ_PENDING 2
	#define RDMAXPRT_CONN_PENDING 3

	#define RPCRDMA_MAX_SVC_SEGS (64) /* server max scatter/gather */
	#if RPCSVC_MAXPAYLOAD < (RPCRDMA_MAX_SVC_SEGS << PAGE_SHIFT)
	#define RPCRDMA_MAXPAYLOAD RPCSVC_MAXPAYLOAD
	#else
	#define RPCRDMA_MAXPAYLOAD (RPCRDMA_MAX_SVC_SEGS << PAGE_SHIFT)
	#endif

	#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_REQUESTS 32
	#define RPCRDMA_MAX_REQ_SIZE 4096

	/* svc_rdma_marshal.c */
	extern int svc_rdma_xdr_decode_req(struct rpcrdma_msg *, struct svc_rqst );
	extern int svc_rdma_xdr_encode_error(struct svcxprt_rdma *,
	struct rpcrdma_msg *,
	enum rpcrdma_errcode, __be32 *);
	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,
	__be32, __be64, 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 *);
	extern int rdma_read_chunk_lcl(struct svcxprt_rdma , struct svc_rqst ,
	struct svc_rdma_op_ctxt , int , u32 *,
	u32, u32, u64, bool);
	extern int rdma_read_chunk_frmr(struct svcxprt_rdma , struct svc_rqst ,
	struct svc_rdma_op_ctxt , int , u32 *,
	u32, u32, u64, bool);

	/* 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);
	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 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt);
	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 int svc_rdma_fastreg(struct svcxprt_rdma , struct svc_rdma_fastreg_mr );
	extern struct svc_rdma_fastreg_mr svc_rdma_get_frmr(struct svcxprt_rdma );
	extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
	struct svc_rdma_fastreg_mr *);
	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[ntohl(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