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/*
* Copyright (c) 2014-2017 Oracle. All rights reserved.
* Copyright (c) 2003-2007 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.
*/
#ifndef _LINUX_SUNRPC_XPRT_RDMA_H
#define _LINUX_SUNRPC_XPRT_RDMA_H
#include <linux/wait.h> /* wait_queue_head_t, etc */
#include <linux/spinlock.h> /* spinlock_t, etc */
#include <linux/atomic.h> /* atomic_t, etc */
#include <linux/workqueue.h> /* struct work_struct */
#include <rdma/rdma_cm.h> /* RDMA connection api */
#include <rdma/ib_verbs.h> /* RDMA verbs api */
#include <linux/sunrpc/clnt.h> /* rpc_xprt */
#include <linux/sunrpc/rpc_rdma.h> /* RPC/RDMA protocol */
#include <linux/sunrpc/xprtrdma.h> /* xprt parameters */
#define RDMA_RESOLVE_TIMEOUT (5000) /* 5 seconds */
#define RDMA_CONNECT_RETRY_MAX (2) /* retries if no listener backlog */
#define RPCRDMA_BIND_TO (60U * HZ)
#define RPCRDMA_INIT_REEST_TO (5U * HZ)
#define RPCRDMA_MAX_REEST_TO (30U * HZ)
#define RPCRDMA_IDLE_DISC_TO (5U * 60 * HZ)
/*
* Interface Adapter -- one per transport instance
*/
struct rpcrdma_ia {
const struct rpcrdma_memreg_ops *ri_ops;
struct ib_device *ri_device;
struct rdma_cm_id *ri_id;
struct ib_pd *ri_pd;
struct completion ri_done;
struct completion ri_remove_done;
int ri_async_rc;
unsigned int ri_max_segs;
unsigned int ri_max_frmr_depth;
unsigned int ri_max_inline_write;
unsigned int ri_max_inline_read;
unsigned int ri_max_send_sges;
bool ri_reminv_expected;
bool ri_implicit_roundup;
enum ib_mr_type ri_mrtype;
unsigned long ri_flags;
struct ib_qp_attr ri_qp_attr;
struct ib_qp_init_attr ri_qp_init_attr;
};
enum {
RPCRDMA_IAF_REMOVING = 0,
};
/*
* RDMA Endpoint -- one per transport instance
*/
struct rpcrdma_ep {
unsigned int rep_send_count;
unsigned int rep_send_batch;
int rep_connected;
struct ib_qp_init_attr rep_attr;
wait_queue_head_t rep_connect_wait;
struct rpcrdma_connect_private rep_cm_private;
struct rdma_conn_param rep_remote_cma;
struct sockaddr_storage rep_remote_addr;
struct delayed_work rep_connect_worker;
};
/* Pre-allocate extra Work Requests for handling backward receives
* and sends. This is a fixed value because the Work Queues are
* allocated when the forward channel is set up.
*/
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
#define RPCRDMA_BACKWARD_WRS (8)
#else
#define RPCRDMA_BACKWARD_WRS (0)
#endif
/* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
*
* The below structure appears at the front of a large region of kmalloc'd
* memory, which always starts on a good alignment boundary.
*/
struct rpcrdma_regbuf {
struct ib_sge rg_iov;
struct ib_device *rg_device;
enum dma_data_direction rg_direction;
__be32 rg_base[0] __attribute__ ((aligned(256)));
};
static inline u64
rdmab_addr(struct rpcrdma_regbuf *rb)
{
return rb->rg_iov.addr;
}
static inline u32
rdmab_length(struct rpcrdma_regbuf *rb)
{
return rb->rg_iov.length;
}
static inline u32
rdmab_lkey(struct rpcrdma_regbuf *rb)
{
return rb->rg_iov.lkey;
}
static inline struct ib_device *
rdmab_device(struct rpcrdma_regbuf *rb)
{
return rb->rg_device;
}
#define RPCRDMA_DEF_GFP (GFP_NOIO | __GFP_NOWARN)
/* To ensure a transport can always make forward progress,
* the number of RDMA segments allowed in header chunk lists
* is capped at 8. This prevents less-capable devices and
* memory registrations from overrunning the Send buffer
* while building chunk lists.
*
* Elements of the Read list take up more room than the
* Write list or Reply chunk. 8 read segments means the Read
* list (or Write list or Reply chunk) cannot consume more
* than
*
* ((8 + 2) * read segment size) + 1 XDR words, or 244 bytes.
*
* And the fixed part of the header is another 24 bytes.
*
* The smallest inline threshold is 1024 bytes, ensuring that
* at least 750 bytes are available for RPC messages.
*/
enum {
RPCRDMA_MAX_HDR_SEGS = 8,
RPCRDMA_HDRBUF_SIZE = 256,
};
/*
* struct rpcrdma_rep -- this structure encapsulates state required
* to receive and complete an RPC Reply, asychronously. It needs
* several pieces of state:
*
* o receive buffer and ib_sge (donated to provider)
* o status of receive (success or not, length, inv rkey)
* o bookkeeping state to get run by reply handler (XDR stream)
*
* These structures are allocated during transport initialization.
* N of these are associated with a transport instance, managed by
* struct rpcrdma_buffer. N is the max number of outstanding RPCs.
*/
struct rpcrdma_rep {
struct ib_cqe rr_cqe;
__be32 rr_xid;
__be32 rr_vers;
__be32 rr_proc;
int rr_wc_flags;
u32 rr_inv_rkey;
struct rpcrdma_regbuf *rr_rdmabuf;
struct rpcrdma_xprt *rr_rxprt;
struct work_struct rr_work;
struct xdr_buf rr_hdrbuf;
struct xdr_stream rr_stream;
struct rpc_rqst *rr_rqst;
struct list_head rr_list;
struct ib_recv_wr rr_recv_wr;
};
/* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
*/
struct rpcrdma_req;
struct rpcrdma_xprt;
struct rpcrdma_sendctx {
struct ib_send_wr sc_wr;
struct ib_cqe sc_cqe;
struct rpcrdma_xprt *sc_xprt;
struct rpcrdma_req *sc_req;
unsigned int sc_unmap_count;
struct ib_sge sc_sges[];
};
/* Limit the number of SGEs that can be unmapped during one
* Send completion. This caps the amount of work a single
* completion can do before returning to the provider.
*
* Setting this to zero disables Send completion batching.
*/
enum {
RPCRDMA_MAX_SEND_BATCH = 7,
};
/*
* struct rpcrdma_mw - external memory region metadata
*
* An external memory region is any buffer or page that is registered
* on the fly (ie, not pre-registered).
*
* Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
* call_allocate, rpcrdma_buffer_get() assigns one to each segment in
* an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
* track of registration metadata while each RPC is pending.
* rpcrdma_deregister_external() uses this metadata to unmap and
* release these resources when an RPC is complete.
*/
enum rpcrdma_frmr_state {
FRMR_IS_INVALID, /* ready to be used */
FRMR_IS_VALID, /* in use */
FRMR_FLUSHED_FR, /* flushed FASTREG WR */
FRMR_FLUSHED_LI, /* flushed LOCALINV WR */
};
struct rpcrdma_frmr {
struct ib_mr *fr_mr;
struct ib_cqe fr_cqe;
enum rpcrdma_frmr_state fr_state;
struct completion fr_linv_done;
union {
struct ib_reg_wr fr_regwr;
struct ib_send_wr fr_invwr;
};
};
struct rpcrdma_fmr {
struct ib_fmr *fm_mr;
u64 *fm_physaddrs;
};
struct rpcrdma_mw {
struct list_head mw_list;
struct scatterlist *mw_sg;
int mw_nents;
enum dma_data_direction mw_dir;
unsigned long mw_flags;
union {
struct rpcrdma_fmr fmr;
struct rpcrdma_frmr frmr;
};
struct rpcrdma_xprt *mw_xprt;
u32 mw_handle;
u32 mw_length;
u64 mw_offset;
struct list_head mw_all;
};
/* mw_flags */
enum {
RPCRDMA_MW_F_RI = 1,
};
/*
* struct rpcrdma_req -- structure central to the request/reply sequence.
*
* N of these are associated with a transport instance, and stored in
* struct rpcrdma_buffer. N is the max number of outstanding requests.
*
* It includes pre-registered buffer memory for send AND recv.
* The recv buffer, however, is not owned by this structure, and
* is "donated" to the hardware when a recv is posted. When a
* reply is handled, the recv buffer used is given back to the
* struct rpcrdma_req associated with the request.
*
* In addition to the basic memory, this structure includes an array
* of iovs for send operations. The reason is that the iovs passed to
* ib_post_{send,recv} must not be modified until the work request
* completes.
*/
/* Maximum number of page-sized "segments" per chunk list to be
* registered or invalidated. Must handle a Reply chunk:
*/
enum {
RPCRDMA_MAX_IOV_SEGS = 3,
RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS +
RPCRDMA_MAX_IOV_SEGS,
};
struct rpcrdma_mr_seg { /* chunk descriptors */
u32 mr_len; /* length of chunk or segment */
struct page *mr_page; /* owning page, if any */
char *mr_offset; /* kva if no page, else offset */
};
/* The Send SGE array is provisioned to send a maximum size
* inline request:
* - RPC-over-RDMA header
* - xdr_buf head iovec
* - RPCRDMA_MAX_INLINE bytes, in pages
* - xdr_buf tail iovec
*
* The actual number of array elements consumed by each RPC
* depends on the device's max_sge limit.
*/
enum {
RPCRDMA_MIN_SEND_SGES = 3,
RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
};
struct rpcrdma_buffer;
struct rpcrdma_req {
struct list_head rl_list;
unsigned int rl_connect_cookie;
struct rpcrdma_buffer *rl_buffer;
struct rpcrdma_rep *rl_reply;
struct xdr_stream rl_stream;
struct xdr_buf rl_hdrbuf;
struct rpcrdma_sendctx *rl_sendctx;
struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */
struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */
struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */
struct list_head rl_all;
unsigned long rl_flags;
struct list_head rl_registered; /* registered segments */
struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS];
};
/* rl_flags */
enum {
RPCRDMA_REQ_F_BACKCHANNEL = 0,
RPCRDMA_REQ_F_PENDING,
RPCRDMA_REQ_F_TX_RESOURCES,
};
static inline void
rpcrdma_set_xprtdata(struct rpc_rqst *rqst, struct rpcrdma_req *req)
{
rqst->rq_xprtdata = req;
}
static inline struct rpcrdma_req *
rpcr_to_rdmar(struct rpc_rqst *rqst)
{
return rqst->rq_xprtdata;
}
static inline void
rpcrdma_push_mw(struct rpcrdma_mw *mw, struct list_head *list)
{
list_add_tail(&mw->mw_list, list);
}
static inline struct rpcrdma_mw *
rpcrdma_pop_mw(struct list_head *list)
{
struct rpcrdma_mw *mw;
mw = list_first_entry(list, struct rpcrdma_mw, mw_list);
list_del(&mw->mw_list);
return mw;
}
/*
* struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
* inline requests/replies, and client/server credits.
*
* One of these is associated with a transport instance
*/
struct rpcrdma_buffer {
spinlock_t rb_mwlock; /* protect rb_mws list */
struct list_head rb_mws;
struct list_head rb_all;
unsigned long rb_sc_head;
unsigned long rb_sc_tail;
unsigned long rb_sc_last;
struct rpcrdma_sendctx **rb_sc_ctxs;
spinlock_t rb_lock; /* protect buf lists */
int rb_send_count, rb_recv_count;
struct list_head rb_send_bufs;
struct list_head rb_recv_bufs;
u32 rb_max_requests;
u32 rb_credits; /* most recent credit grant */
u32 rb_bc_srv_max_requests;
spinlock_t rb_reqslock; /* protect rb_allreqs */
struct list_head rb_allreqs;
u32 rb_bc_max_requests;
spinlock_t rb_recovery_lock; /* protect rb_stale_mrs */
struct list_head rb_stale_mrs;
struct delayed_work rb_recovery_worker;
struct delayed_work rb_refresh_worker;
};
#define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
/*
* Internal structure for transport instance creation. This
* exists primarily for modularity.
*
* This data should be set with mount options
*/
struct rpcrdma_create_data_internal {
struct sockaddr_storage addr; /* RDMA server address */
unsigned int max_requests; /* max requests (slots) in flight */
unsigned int rsize; /* mount rsize - max read hdr+data */
unsigned int wsize; /* mount wsize - max write hdr+data */
unsigned int inline_rsize; /* max non-rdma read data payload */
unsigned int inline_wsize; /* max non-rdma write data payload */
unsigned int padding; /* non-rdma write header padding */
};
/*
* Statistics for RPCRDMA
*/
struct rpcrdma_stats {
/* accessed when sending a call */
unsigned long read_chunk_count;
unsigned long write_chunk_count;
unsigned long reply_chunk_count;
unsigned long long total_rdma_request;
/* rarely accessed error counters */
unsigned long long pullup_copy_count;
unsigned long hardway_register_count;
unsigned long failed_marshal_count;
unsigned long bad_reply_count;
unsigned long mrs_recovered;
unsigned long mrs_orphaned;
unsigned long mrs_allocated;
unsigned long empty_sendctx_q;
/* accessed when receiving a reply */
unsigned long long total_rdma_reply;
unsigned long long fixup_copy_count;
unsigned long reply_waits_for_send;
unsigned long local_inv_needed;
unsigned long nomsg_call_count;
unsigned long bcall_count;
};
/*
* Per-registration mode operations
*/
struct rpcrdma_xprt;
struct rpcrdma_memreg_ops {
struct rpcrdma_mr_seg *
(*ro_map)(struct rpcrdma_xprt *,
struct rpcrdma_mr_seg *, int, bool,
struct rpcrdma_mw **);
void (*ro_unmap_sync)(struct rpcrdma_xprt *,
struct list_head *);
void (*ro_recover_mr)(struct rpcrdma_mw *);
int (*ro_open)(struct rpcrdma_ia *,
struct rpcrdma_ep *,
struct rpcrdma_create_data_internal *);
size_t (*ro_maxpages)(struct rpcrdma_xprt *);
int (*ro_init_mr)(struct rpcrdma_ia *,
struct rpcrdma_mw *);
void (*ro_release_mr)(struct rpcrdma_mw *);
const char *ro_displayname;
const int ro_send_w_inv_ok;
};
extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
/*
* RPCRDMA transport -- encapsulates the structures above for
* integration with RPC.
*
* The contained structures are embedded, not pointers,
* for convenience. This structure need not be visible externally.
*
* It is allocated and initialized during mount, and released
* during unmount.
*/
struct rpcrdma_xprt {
struct rpc_xprt rx_xprt;
struct rpcrdma_ia rx_ia;
struct rpcrdma_ep rx_ep;
struct rpcrdma_buffer rx_buf;
struct rpcrdma_create_data_internal rx_data;
struct delayed_work rx_connect_worker;
struct rpcrdma_stats rx_stats;
};
#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
#define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
/* Setting this to 0 ensures interoperability with early servers.
* Setting this to 1 enhances certain unaligned read/write performance.
* Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
extern int xprt_rdma_pad_optimize;
/* This setting controls the hunt for a supported memory
* registration strategy.
*/
extern unsigned int xprt_rdma_memreg_strategy;
/*
* Interface Adapter calls - xprtrdma/verbs.c
*/
int rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr);
void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
void rpcrdma_ia_close(struct rpcrdma_ia *);
bool frwr_is_supported(struct rpcrdma_ia *);
bool fmr_is_supported(struct rpcrdma_ia *);
extern struct workqueue_struct *rpcrdma_receive_wq;
/*
* Endpoint calls - xprtrdma/verbs.c
*/
int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
struct rpcrdma_create_data_internal *);
void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
void rpcrdma_conn_func(struct rpcrdma_ep *ep);
void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
struct rpcrdma_req *);
int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_rep *);
/*
* Buffer calls - xprtrdma/verbs.c
*/
struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
void rpcrdma_destroy_req(struct rpcrdma_req *);
int rpcrdma_buffer_create(struct rpcrdma_xprt *);
void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf);
void rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc);
struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
void rpcrdma_buffer_put(struct rpcrdma_req *);
void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
void rpcrdma_defer_mr_recovery(struct rpcrdma_mw *);
struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(size_t, enum dma_data_direction,
gfp_t);
bool __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *, struct rpcrdma_regbuf *);
void rpcrdma_free_regbuf(struct rpcrdma_regbuf *);
static inline bool
rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
{
return rb->rg_device != NULL;
}
static inline bool
rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
{
if (likely(rpcrdma_regbuf_is_mapped(rb)))
return true;
return __rpcrdma_dma_map_regbuf(ia, rb);
}
int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
int rpcrdma_alloc_wq(void);
void rpcrdma_destroy_wq(void);
/*
* Wrappers for chunk registration, shared by read/write chunk code.
*/
static inline enum dma_data_direction
rpcrdma_data_dir(bool writing)
{
return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
}
/*
* RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
*/
enum rpcrdma_chunktype {
rpcrdma_noch = 0,
rpcrdma_readch,
rpcrdma_areadch,
rpcrdma_writech,
rpcrdma_replych
};
int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req, u32 hdrlen,
struct xdr_buf *xdr,
enum rpcrdma_chunktype rtype);
void rpcrdma_unmap_sendctx(struct rpcrdma_sendctx *sc);
int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
void rpcrdma_complete_rqst(struct rpcrdma_rep *rep);
void rpcrdma_reply_handler(struct rpcrdma_rep *rep);
void rpcrdma_release_rqst(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req);
void rpcrdma_deferred_completion(struct work_struct *work);
static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
{
xdr->head[0].iov_len = len;
xdr->len = len;
}
/* RPC/RDMA module init - xprtrdma/transport.c
*/
extern unsigned int xprt_rdma_max_inline_read;
void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
void rpcrdma_connect_worker(struct work_struct *work);
void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
int xprt_rdma_init(void);
void xprt_rdma_cleanup(void);
/* Backchannel calls - xprtrdma/backchannel.c
*/
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
int xprt_rdma_bc_up(struct svc_serv *, struct net *);
size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
extern struct xprt_class xprt_rdma_bc;
#endif /* _LINUX_SUNRPC_XPRT_RDMA_H */