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

 /*
  *  linux/include/linux/sunrpc/xprt.h
  *
  *  Declarations for the RPC transport interface.
  *
  *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
  */

 #ifndef _LINUX_SUNRPC_XPRT_H
 #define _LINUX_SUNRPC_XPRT_H

 #include <linux/uio.h>
 #include <linux/socket.h>
 #include <linux/in.h>
 #include <linux/ktime.h>
 #include <linux/kref.h>
 #include <linux/sunrpc/sched.h>
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/msg_prot.h>

 #ifdef __KERNEL__

 #define RPC_MIN_SLOT_TABLE	(2U)
 #define RPC_DEF_SLOT_TABLE	(16U)
 #define RPC_MAX_SLOT_TABLE_LIMIT	(65536U)
 #define RPC_MAX_SLOT_TABLE	RPC_MAX_SLOT_TABLE_LIMIT

 #define RPC_CWNDSHIFT		(8U)
 #define RPC_CWNDSCALE		(1U << RPC_CWNDSHIFT)
 #define RPC_INITCWND		RPC_CWNDSCALE
 #define RPC_MAXCWND(xprt)	((xprt)->max_reqs << RPC_CWNDSHIFT)
 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)

 /*
  * This describes a timeout strategy
  */
 struct rpc_timeout {
 	unsigned long		to_initval,		/* initial timeout */
 				to_maxval,		/* max timeout */
 				to_increment;		/* if !exponential */
 	unsigned int		to_retries;		/* max # of retries */
 	unsigned char		to_exponential;
 };

 enum rpc_display_format_t {
 	RPC_DISPLAY_ADDR = 0,
 	RPC_DISPLAY_PORT,
 	RPC_DISPLAY_PROTO,
 	RPC_DISPLAY_HEX_ADDR,
 	RPC_DISPLAY_HEX_PORT,
 	RPC_DISPLAY_NETID,
 	RPC_DISPLAY_MAX,
 };

 struct rpc_task;
 struct rpc_xprt;
 struct seq_file;
 struct svc_serv;
 struct net;

 /*
  * This describes a complete RPC request
  */
 struct rpc_rqst {
 	/*
 	 * This is the user-visible part
 	 */
 	struct rpc_xprt *	rq_xprt;		/* RPC client */
 	struct xdr_buf		rq_snd_buf;		/* send buffer */
 	struct xdr_buf		rq_rcv_buf;		/* recv buffer */

 	/*
 	 * This is the private part
 	 */
 	struct rpc_task *	rq_task;	/* RPC task data */
 	struct rpc_cred *	rq_cred;	/* Bound cred */
 	__be32			rq_xid;		/* request XID */
 	int			rq_cong;	/* has incremented xprt->cong */
 	u32			rq_seqno;	/* gss seq no. used on req. */
 	int			rq_enc_pages_num;
 	struct page		**rq_enc_pages;	/* scratch pages for use by
 						   gss privacy code */
 	void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
 	struct list_head	rq_list;

 	void			*rq_xprtdata;	/* Per-xprt private data */
 	void			*rq_buffer;	/* Call XDR encode buffer */
 	size_t			rq_callsize;
 	void			*rq_rbuffer;	/* Reply XDR decode buffer */
 	size_t			rq_rcvsize;
 	size_t			rq_xmit_bytes_sent;	/* total bytes sent */
 	size_t			rq_reply_bytes_recvd;	/* total reply bytes */
 							/* received */

 	struct xdr_buf		rq_private_buf;		/* The receive buffer
 							 * used in the softirq.
 							 */
 	unsigned long		rq_majortimeo;	/* major timeout alarm */
 	unsigned long		rq_timeout;	/* Current timeout value */
 	ktime_t			rq_rtt;		/* round-trip time */
 	unsigned int		rq_retries;	/* # of retries */
 	unsigned int		rq_connect_cookie;
 						/* A cookie used to track the
 						   state of the transport
 						   connection */

 	/*
 	 * Partial send handling
 	 */
 	u32			rq_bytes_sent;	/* Bytes we have sent */

 	ktime_t			rq_xtime;	/* transmit time stamp */
 	int			rq_ntrans;

 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 	struct list_head	rq_bc_list;	/* Callback service list */
 	unsigned long		rq_bc_pa_state;	/* Backchannel prealloc state */
 	struct list_head	rq_bc_pa_list;	/* Backchannel prealloc list */
 #endif /* CONFIG_SUNRPC_BACKCHANEL */
 };
 #define rq_svec			rq_snd_buf.head
 #define rq_slen			rq_snd_buf.len

 struct rpc_xprt_ops {
 	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
 	int		(*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
 	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
 	void		(*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
 	void		(*rpcbind)(struct rpc_task *task);
 	void		(*set_port)(struct rpc_xprt *xprt, unsigned short port);
 	void		(*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
 	int		(*buf_alloc)(struct rpc_task *task);
 	void		(*buf_free)(struct rpc_task *task);
 	int		(*send_request)(struct rpc_task *task);
 	void		(*set_retrans_timeout)(struct rpc_task *task);
 	void		(*timer)(struct rpc_xprt *xprt, struct rpc_task *task);
 	void		(*release_request)(struct rpc_task *task);
 	void		(*close)(struct rpc_xprt *xprt);
 	void		(*destroy)(struct rpc_xprt *xprt);
 	void		(*set_connect_timeout)(struct rpc_xprt *xprt,
 					unsigned long connect_timeout,
 					unsigned long reconnect_timeout);
 	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
 	int		(*enable_swap)(struct rpc_xprt *xprt);
 	void		(*disable_swap)(struct rpc_xprt *xprt);
 	void		(*inject_disconnect)(struct rpc_xprt *xprt);
 	int		(*bc_setup)(struct rpc_xprt *xprt,
 				    unsigned int min_reqs);
 	int		(*bc_up)(struct svc_serv *serv, struct net *net);
 	size_t		(*bc_maxpayload)(struct rpc_xprt *xprt);
 	void		(*bc_free_rqst)(struct rpc_rqst *rqst);
 	void		(*bc_destroy)(struct rpc_xprt *xprt,
 				      unsigned int max_reqs);
 };

 /*
  * RPC transport identifiers
  *
  * To preserve compatibility with the historical use of raw IP protocol
  * id's for transport selection, UDP and TCP identifiers are specified
  * with the previous values. No such restriction exists for new transports,
  * except that they may not collide with these values (17 and 6,
  * respectively).
  */
 #define XPRT_TRANSPORT_BC       (1 << 31)
 enum xprt_transports {
 	XPRT_TRANSPORT_UDP	= IPPROTO_UDP,
 	XPRT_TRANSPORT_TCP	= IPPROTO_TCP,
 	XPRT_TRANSPORT_BC_TCP	= IPPROTO_TCP | XPRT_TRANSPORT_BC,
 	XPRT_TRANSPORT_RDMA	= 256,
 	XPRT_TRANSPORT_BC_RDMA	= XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
 	XPRT_TRANSPORT_LOCAL	= 257,
 };

 struct rpc_xprt {
 	struct kref		kref;		/* Reference count */
 	struct rpc_xprt_ops *	ops;		/* transport methods */

 	const struct rpc_timeout *timeout;	/* timeout parms */
 	struct sockaddr_storage	addr;		/* server address */
 	size_t			addrlen;	/* size of server address */
 	int			prot;		/* IP protocol */

 	unsigned long		cong;		/* current congestion */
 	unsigned long		cwnd;		/* congestion window */

 	size_t			max_payload;	/* largest RPC payload size,
 						   in bytes */
 	unsigned int		tsh_size;	/* size of transport specific
 						   header */

 	struct rpc_wait_queue	binding;	/* requests waiting on rpcbind */
 	struct rpc_wait_queue	sending;	/* requests waiting to send */
 	struct rpc_wait_queue	pending;	/* requests in flight */
 	struct rpc_wait_queue	backlog;	/* waiting for slot */
 	struct list_head	free;		/* free slots */
 	unsigned int		max_reqs;	/* max number of slots */
 	unsigned int		min_reqs;	/* min number of slots */
 	atomic_t		num_reqs;	/* total slots */
 	unsigned long		state;		/* transport state */
 	unsigned char		resvport   : 1; /* use a reserved port */
 	atomic_t		swapper;	/* we're swapping over this
 						   transport */
 	unsigned int		bind_index;	/* bind function index */

 	/*
 	 * Multipath
 	 */
 	struct list_head	xprt_switch;

 	/*
 	 * Connection of transports
 	 */
 	unsigned long		bind_timeout,
 				reestablish_timeout;
 	unsigned int		connect_cookie;	/* A cookie that gets bumped
 						   every time the transport
 						   is reconnected */

 	/*
 	 * Disconnection of idle transports
 	 */
 	struct work_struct	task_cleanup;
 	struct timer_list	timer;
 	unsigned long		last_used,
 				idle_timeout,
 				connect_timeout,
 				max_reconnect_timeout;

 	/*
 	 * Send stuff
 	 */
 	spinlock_t		transport_lock;	/* lock transport info */
 	spinlock_t		reserve_lock;	/* lock slot table */
 	u32			xid;		/* Next XID value to use */
 	struct rpc_task *	snd_task;	/* Task blocked in send */
 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 	struct svc_serv		*bc_serv;       /* The RPC service which will */
 						/* process the callback */
 	int			bc_alloc_count;	/* Total number of preallocs */
 	atomic_t		bc_free_slots;
 	spinlock_t		bc_pa_lock;	/* Protects the preallocated
 						 * items */
 	struct list_head	bc_pa_list;	/* List of preallocated
 						 * backchannel rpc_rqst's */
 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 	struct list_head	recv;

 	struct {
 		unsigned long		bind_count,	/* total number of binds */
 					connect_count,	/* total number of connects */
 					connect_start,	/* connect start timestamp */
 					connect_time,	/* jiffies waiting for connect */
 					sends,		/* how many complete requests */
 					recvs,		/* how many complete requests */
 					bad_xids,	/* lookup_rqst didn't find XID */
 					max_slots;	/* max rpc_slots used */

 		unsigned long long	req_u,		/* average requests on the wire */
 					bklog_u,	/* backlog queue utilization */
 					sending_u,	/* send q utilization */
 					pending_u;	/* pend q utilization */
 	} stat;

 	struct net		*xprt_net;
 	const char		*servername;
 	const char		*address_strings[RPC_DISPLAY_MAX];
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	struct dentry		*debugfs;		/* debugfs directory */
 	atomic_t		inject_disconnect;
 #endif
 	struct rcu_head		rcu;
 };

 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 /*
  * Backchannel flags
  */
 #define	RPC_BC_PA_IN_USE	0x0001		/* Preallocated backchannel */
 						/* buffer in use */
 #endif /* CONFIG_SUNRPC_BACKCHANNEL */

 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 static inline int bc_prealloc(struct rpc_rqst *req)
 {
 	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 }
 #else
 static inline int bc_prealloc(struct rpc_rqst *req)
 {
 	return 0;
 }
 #endif /* CONFIG_SUNRPC_BACKCHANNEL */

 #define XPRT_CREATE_INFINITE_SLOTS	(1U)
 #define XPRT_CREATE_NO_IDLE_TIMEOUT	(1U << 1)

 struct xprt_create {
 	int			ident;		/* XPRT_TRANSPORT identifier */
 	struct net *		net;
 	struct sockaddr *	srcaddr;	/* optional local address */
 	struct sockaddr *	dstaddr;	/* remote peer address */
 	size_t			addrlen;
 	const char		*servername;
 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
 	struct rpc_xprt_switch	*bc_xps;
 	unsigned int		flags;
 };

 struct xprt_class {
 	struct list_head	list;
 	int			ident;		/* XPRT_TRANSPORT identifier */
 	struct rpc_xprt *	(*setup)(struct xprt_create *);
 	struct module		*owner;
 	char			name[32];
 };

 /*
  * Generic internal transport functions
  */
 struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);
 void			xprt_connect(struct rpc_task *task);
 void			xprt_reserve(struct rpc_task *task);
 void			xprt_retry_reserve(struct rpc_task *task);
 int			xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 int			xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 void			xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 void			xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 bool			xprt_prepare_transmit(struct rpc_task *task);
 void			xprt_transmit(struct rpc_task *task);
 void			xprt_end_transmit(struct rpc_task *task);
 int			xprt_adjust_timeout(struct rpc_rqst *req);
 void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 void			xprt_release(struct rpc_task *task);
 struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
 void			xprt_put(struct rpc_xprt *xprt);
 struct rpc_xprt *	xprt_alloc(struct net *net, size_t size,
 				unsigned int num_prealloc,
 				unsigned int max_req);
 void			xprt_free(struct rpc_xprt *);

 static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
 {
 	return p + xprt->tsh_size;
 }

 static inline int
 xprt_enable_swap(struct rpc_xprt *xprt)
 {
 	return xprt->ops->enable_swap(xprt);
 }

 static inline void
 xprt_disable_swap(struct rpc_xprt *xprt)
 {
 	xprt->ops->disable_swap(xprt);
 }

 /*
  * Transport switch helper functions
  */
 int			xprt_register_transport(struct xprt_class *type);
 int			xprt_unregister_transport(struct xprt_class *type);
 int			xprt_load_transport(const char *);
 void			xprt_set_retrans_timeout_def(struct rpc_task *task);
 void			xprt_set_retrans_timeout_rtt(struct rpc_task *task);
 void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
 void			xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
 void			xprt_write_space(struct rpc_xprt *xprt);
 void			xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
 void			xprt_complete_rqst(struct rpc_task *task, int copied);
 void			xprt_release_rqst_cong(struct rpc_task *task);
 void			xprt_disconnect_done(struct rpc_xprt *xprt);
 void			xprt_force_disconnect(struct rpc_xprt *xprt);
 void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);

 bool			xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
 void			xprt_unlock_connect(struct rpc_xprt *, void *);

 /*
  * Reserved bit positions in xprt->state
  */
 #define XPRT_LOCKED		(0)
 #define XPRT_CONNECTED		(1)
 #define XPRT_CONNECTING		(2)
 #define XPRT_CLOSE_WAIT		(3)
 #define XPRT_BOUND		(4)
 #define XPRT_BINDING		(5)
 #define XPRT_CLOSING		(6)
 #define XPRT_CONGESTED		(9)

 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 {
 	set_bit(XPRT_CONNECTED, &xprt->state);
 }

 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
 {
 	clear_bit(XPRT_CONNECTED, &xprt->state);
 }

 static inline int xprt_connected(struct rpc_xprt *xprt)
 {
 	return test_bit(XPRT_CONNECTED, &xprt->state);
 }

 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
 {
 	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
 }

 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
 {
 	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
 }

 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
 {
 	smp_mb__before_atomic();
 	clear_bit(XPRT_CONNECTING, &xprt->state);
 	smp_mb__after_atomic();
 }

 static inline int xprt_connecting(struct rpc_xprt *xprt)
 {
 	return test_bit(XPRT_CONNECTING, &xprt->state);
 }

 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
 {
 	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
 }

 static inline void xprt_set_bound(struct rpc_xprt *xprt)
 {
 	test_and_set_bit(XPRT_BOUND, &xprt->state);
 }

 static inline int xprt_bound(struct rpc_xprt *xprt)
 {
 	return test_bit(XPRT_BOUND, &xprt->state);
 }

 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
 {
 	clear_bit(XPRT_BOUND, &xprt->state);
 }

 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
 {
 	smp_mb__before_atomic();
 	clear_bit(XPRT_BINDING, &xprt->state);
 	smp_mb__after_atomic();
 }

 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
 {
 	return test_and_set_bit(XPRT_BINDING, &xprt->state);
 }

 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 extern unsigned int rpc_inject_disconnect;
 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 {
 	if (!rpc_inject_disconnect)
 		return;
 	if (atomic_dec_return(&xprt->inject_disconnect))
 		return;
 	atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
 	xprt->ops->inject_disconnect(xprt);
 }
 #else
 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 {
 }
 #endif

 #endif /* __KERNEL__*/

 #endif /* _LINUX_SUNRPC_XPRT_H */
	/*
	* linux/include/linux/sunrpc/xprt.h
	*
	* Declarations for the RPC transport interface.
	*
	* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
	*/

	#ifndef _LINUX_SUNRPC_XPRT_H
	#define _LINUX_SUNRPC_XPRT_H

	#include <linux/uio.h>
	#include <linux/socket.h>
	#include <linux/in.h>
	#include <linux/ktime.h>
	#include <linux/kref.h>
	#include <linux/sunrpc/sched.h>
	#include <linux/sunrpc/xdr.h>
	#include <linux/sunrpc/msg_prot.h>

	#ifdef __KERNEL__

	#define RPC_MIN_SLOT_TABLE (2U)
	#define RPC_DEF_SLOT_TABLE (16U)
	#define RPC_MAX_SLOT_TABLE_LIMIT (65536U)
	#define RPC_MAX_SLOT_TABLE RPC_MAX_SLOT_TABLE_LIMIT

	#define RPC_CWNDSHIFT (8U)
	#define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT)
	#define RPC_INITCWND RPC_CWNDSCALE
	#define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT)
	#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)

	/*
	* This describes a timeout strategy
	*/
	struct rpc_timeout {
	unsigned long to_initval, /* initial timeout */
	to_maxval, /* max timeout */
	to_increment; /* if !exponential */
	unsigned int to_retries; /* max # of retries */
	unsigned char to_exponential;
	};

	enum rpc_display_format_t {
	RPC_DISPLAY_ADDR = 0,
	RPC_DISPLAY_PORT,
	RPC_DISPLAY_PROTO,
	RPC_DISPLAY_HEX_ADDR,
	RPC_DISPLAY_HEX_PORT,
	RPC_DISPLAY_NETID,
	RPC_DISPLAY_MAX,
	};

	struct rpc_task;
	struct rpc_xprt;
	struct seq_file;
	struct svc_serv;
	struct net;

	/*
	* This describes a complete RPC request
	*/
	struct rpc_rqst {
	/*
	* This is the user-visible part
	*/
	struct rpc_xprt * rq_xprt; /* RPC client */
	struct xdr_buf rq_snd_buf; /* send buffer */
	struct xdr_buf rq_rcv_buf; /* recv buffer */

	/*
	* This is the private part
	*/
	struct rpc_task * rq_task; /* RPC task data */
	struct rpc_cred * rq_cred; /* Bound cred */
	__be32 rq_xid; /* request XID */
	int rq_cong; /* has incremented xprt->cong */
	u32 rq_seqno; /* gss seq no. used on req. */
	int rq_enc_pages_num;
	struct page *rq_enc_pages; / scratch pages for use by
	gss privacy code */
	void (rq_release_snd_buf)(struct rpc_rqst ); /* release rq_enc_pages */
	struct list_head rq_list;

	void rq_xprtdata; / Per-xprt private data */
	void rq_buffer; / Call XDR encode buffer */
	size_t rq_callsize;
	void rq_rbuffer; / Reply XDR decode buffer */
	size_t rq_rcvsize;
	size_t rq_xmit_bytes_sent; /* total bytes sent */
	size_t rq_reply_bytes_recvd; /* total reply bytes */
	/* received */

	struct xdr_buf rq_private_buf; /* The receive buffer
	* used in the softirq.
	*/
	unsigned long rq_majortimeo; /* major timeout alarm */
	unsigned long rq_timeout; /* Current timeout value */
	ktime_t rq_rtt; /* round-trip time */
	unsigned int rq_retries; /* # of retries */
	unsigned int rq_connect_cookie;
	/* A cookie used to track the
	state of the transport
	connection */

	/*
	* Partial send handling
	*/
	u32 rq_bytes_sent; /* Bytes we have sent */

	ktime_t rq_xtime; /* transmit time stamp */
	int rq_ntrans;

	#if defined(CONFIG_SUNRPC_BACKCHANNEL)
	struct list_head rq_bc_list; /* Callback service list */
	unsigned long rq_bc_pa_state; /* Backchannel prealloc state */
	struct list_head rq_bc_pa_list; /* Backchannel prealloc list */
	#endif /* CONFIG_SUNRPC_BACKCHANEL */
	};
	#define rq_svec rq_snd_buf.head
	#define rq_slen rq_snd_buf.len

	struct rpc_xprt_ops {
	void (set_buffer_size)(struct rpc_xprt xprt, size_t sndsize, size_t rcvsize);
	int (reserve_xprt)(struct rpc_xprt xprt, struct rpc_task *task);
	void (release_xprt)(struct rpc_xprt xprt, struct rpc_task *task);
	void (alloc_slot)(struct rpc_xprt xprt, struct rpc_task *task);
	void (rpcbind)(struct rpc_task task);
	void (set_port)(struct rpc_xprt xprt, unsigned short port);
	void (connect)(struct rpc_xprt xprt, struct rpc_task *task);
	int (buf_alloc)(struct rpc_task task);
	void (buf_free)(struct rpc_task task);
	int (send_request)(struct rpc_task task);
	void (set_retrans_timeout)(struct rpc_task task);
	void (timer)(struct rpc_xprt xprt, struct rpc_task *task);
	void (release_request)(struct rpc_task task);
	void (close)(struct rpc_xprt xprt);
	void (destroy)(struct rpc_xprt xprt);
	void (set_connect_timeout)(struct rpc_xprt xprt,
	unsigned long connect_timeout,
	unsigned long reconnect_timeout);
	void (print_stats)(struct rpc_xprt xprt, struct seq_file *seq);
	int (enable_swap)(struct rpc_xprt xprt);
	void (disable_swap)(struct rpc_xprt xprt);
	void (inject_disconnect)(struct rpc_xprt xprt);
	int (bc_setup)(struct rpc_xprt xprt,
	unsigned int min_reqs);
	int (bc_up)(struct svc_serv serv, struct net *net);
	size_t (bc_maxpayload)(struct rpc_xprt xprt);
	void (bc_free_rqst)(struct rpc_rqst rqst);
	void (bc_destroy)(struct rpc_xprt xprt,
	unsigned int max_reqs);
	};

	/*
	* RPC transport identifiers
	*
	* To preserve compatibility with the historical use of raw IP protocol
	* id's for transport selection, UDP and TCP identifiers are specified
	* with the previous values. No such restriction exists for new transports,
	* except that they may not collide with these values (17 and 6,
	* respectively).
	*/
	#define XPRT_TRANSPORT_BC (1 << 31)
	enum xprt_transports {
	XPRT_TRANSPORT_UDP = IPPROTO_UDP,
	XPRT_TRANSPORT_TCP = IPPROTO_TCP,
	XPRT_TRANSPORT_BC_TCP = IPPROTO_TCP \| XPRT_TRANSPORT_BC,
	XPRT_TRANSPORT_RDMA = 256,
	XPRT_TRANSPORT_BC_RDMA = XPRT_TRANSPORT_RDMA \| XPRT_TRANSPORT_BC,
	XPRT_TRANSPORT_LOCAL = 257,
	};

	struct rpc_xprt {
	struct kref kref; /* Reference count */
	struct rpc_xprt_ops * ops; /* transport methods */

	const struct rpc_timeout timeout; / timeout parms */
	struct sockaddr_storage addr; /* server address */
	size_t addrlen; /* size of server address */
	int prot; /* IP protocol */

	unsigned long cong; /* current congestion */
	unsigned long cwnd; /* congestion window */

	size_t max_payload; /* largest RPC payload size,
	in bytes */
	unsigned int tsh_size; /* size of transport specific
	header */

	struct rpc_wait_queue binding; /* requests waiting on rpcbind */
	struct rpc_wait_queue sending; /* requests waiting to send */
	struct rpc_wait_queue pending; /* requests in flight */
	struct rpc_wait_queue backlog; /* waiting for slot */
	struct list_head free; /* free slots */
	unsigned int max_reqs; /* max number of slots */
	unsigned int min_reqs; /* min number of slots */
	atomic_t num_reqs; /* total slots */
	unsigned long state; /* transport state */
	unsigned char resvport : 1; /* use a reserved port */
	atomic_t swapper; /* we're swapping over this
	transport */
	unsigned int bind_index; /* bind function index */

	/*
	* Multipath
	*/
	struct list_head xprt_switch;

	/*
	* Connection of transports
	*/
	unsigned long bind_timeout,
	reestablish_timeout;
	unsigned int connect_cookie; /* A cookie that gets bumped
	every time the transport
	is reconnected */

	/*
	* Disconnection of idle transports
	*/
	struct work_struct task_cleanup;
	struct timer_list timer;
	unsigned long last_used,
	idle_timeout,
	connect_timeout,
	max_reconnect_timeout;

	/*
	* Send stuff
	*/
	spinlock_t transport_lock; /* lock transport info */
	spinlock_t reserve_lock; /* lock slot table */
	u32 xid; /* Next XID value to use */
	struct rpc_task * snd_task; /* Task blocked in send */
	struct svc_xprt bc_xprt; / NFSv4.1 backchannel */
	#if defined(CONFIG_SUNRPC_BACKCHANNEL)
	struct svc_serv bc_serv; / The RPC service which will */
	/* process the callback */
	int bc_alloc_count; /* Total number of preallocs */
	atomic_t bc_free_slots;
	spinlock_t bc_pa_lock; /* Protects the preallocated
	* items */
	struct list_head bc_pa_list; /* List of preallocated
	* backchannel rpc_rqst's */
	#endif /* CONFIG_SUNRPC_BACKCHANNEL */
	struct list_head recv;

	struct {
	unsigned long bind_count, /* total number of binds */
	connect_count, /* total number of connects */
	connect_start, /* connect start timestamp */
	connect_time, /* jiffies waiting for connect */
	sends, /* how many complete requests */
	recvs, /* how many complete requests */
	bad_xids, /* lookup_rqst didn't find XID */
	max_slots; /* max rpc_slots used */

	unsigned long long req_u, /* average requests on the wire */
	bklog_u, /* backlog queue utilization */
	sending_u, /* send q utilization */
	pending_u; /* pend q utilization */
	} stat;

	struct net *xprt_net;
	const char *servername;
	const char *address_strings[RPC_DISPLAY_MAX];
	#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
	struct dentry debugfs; / debugfs directory */
	atomic_t inject_disconnect;
	#endif
	struct rcu_head rcu;
	};

	#if defined(CONFIG_SUNRPC_BACKCHANNEL)
	/*
	* Backchannel flags
	*/
	#define RPC_BC_PA_IN_USE 0x0001 /* Preallocated backchannel */
	/* buffer in use */
	#endif /* CONFIG_SUNRPC_BACKCHANNEL */

	#if defined(CONFIG_SUNRPC_BACKCHANNEL)
	static inline int bc_prealloc(struct rpc_rqst *req)
	{
	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
	}
	#else
	static inline int bc_prealloc(struct rpc_rqst *req)
	{
	return 0;
	}
	#endif /* CONFIG_SUNRPC_BACKCHANNEL */

	#define XPRT_CREATE_INFINITE_SLOTS (1U)
	#define XPRT_CREATE_NO_IDLE_TIMEOUT (1U << 1)

	struct xprt_create {
	int ident; /* XPRT_TRANSPORT identifier */
	struct net * net;
	struct sockaddr * srcaddr; /* optional local address */
	struct sockaddr * dstaddr; /* remote peer address */
	size_t addrlen;
	const char *servername;
	struct svc_xprt bc_xprt; / NFSv4.1 backchannel */
	struct rpc_xprt_switch *bc_xps;
	unsigned int flags;
	};

	struct xprt_class {
	struct list_head list;
	int ident; /* XPRT_TRANSPORT identifier */
	struct rpc_xprt * (setup)(struct xprt_create );
	struct module *owner;
	char name[32];
	};

	/*
	* Generic internal transport functions
	*/
	struct rpc_xprt xprt_create_transport(struct xprt_create args);
	void xprt_connect(struct rpc_task *task);
	void xprt_reserve(struct rpc_task *task);
	void xprt_retry_reserve(struct rpc_task *task);
	int xprt_reserve_xprt(struct rpc_xprt xprt, struct rpc_task task);
	int xprt_reserve_xprt_cong(struct rpc_xprt xprt, struct rpc_task task);
	void xprt_alloc_slot(struct rpc_xprt xprt, struct rpc_task task);
	void xprt_lock_and_alloc_slot(struct rpc_xprt xprt, struct rpc_task task);
	bool xprt_prepare_transmit(struct rpc_task *task);
	void xprt_transmit(struct rpc_task *task);
	void xprt_end_transmit(struct rpc_task *task);
	int xprt_adjust_timeout(struct rpc_rqst *req);
	void xprt_release_xprt(struct rpc_xprt xprt, struct rpc_task task);
	void xprt_release_xprt_cong(struct rpc_xprt xprt, struct rpc_task task);
	void xprt_release(struct rpc_task *task);
	struct rpc_xprt * xprt_get(struct rpc_xprt *xprt);
	void xprt_put(struct rpc_xprt *xprt);
	struct rpc_xprt * xprt_alloc(struct net *net, size_t size,
	unsigned int num_prealloc,
	unsigned int max_req);
	void xprt_free(struct rpc_xprt *);

	static inline __be32 xprt_skip_transport_header(struct rpc_xprt xprt, __be32 *p)
	{
	return p + xprt->tsh_size;
	}

	static inline int
	xprt_enable_swap(struct rpc_xprt *xprt)
	{
	return xprt->ops->enable_swap(xprt);
	}

	static inline void
	xprt_disable_swap(struct rpc_xprt *xprt)
	{
	xprt->ops->disable_swap(xprt);
	}

	/*
	* Transport switch helper functions
	*/
	int xprt_register_transport(struct xprt_class *type);
	int xprt_unregister_transport(struct xprt_class *type);
	int xprt_load_transport(const char *);
	void xprt_set_retrans_timeout_def(struct rpc_task *task);
	void xprt_set_retrans_timeout_rtt(struct rpc_task *task);
	void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
	void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
	void xprt_write_space(struct rpc_xprt *xprt);
	void xprt_adjust_cwnd(struct rpc_xprt xprt, struct rpc_task task, int result);
	struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
	void xprt_complete_rqst(struct rpc_task *task, int copied);
	void xprt_release_rqst_cong(struct rpc_task *task);
	void xprt_disconnect_done(struct rpc_xprt *xprt);
	void xprt_force_disconnect(struct rpc_xprt *xprt);
	void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);

	bool xprt_lock_connect(struct rpc_xprt , struct rpc_task , void *);
	void xprt_unlock_connect(struct rpc_xprt , void );

	/*
	* Reserved bit positions in xprt->state
	*/
	#define XPRT_LOCKED (0)
	#define XPRT_CONNECTED (1)
	#define XPRT_CONNECTING (2)
	#define XPRT_CLOSE_WAIT (3)
	#define XPRT_BOUND (4)
	#define XPRT_BINDING (5)
	#define XPRT_CLOSING (6)
	#define XPRT_CONGESTED (9)

	static inline void xprt_set_connected(struct rpc_xprt *xprt)
	{
	set_bit(XPRT_CONNECTED, &xprt->state);
	}

	static inline void xprt_clear_connected(struct rpc_xprt *xprt)
	{
	clear_bit(XPRT_CONNECTED, &xprt->state);
	}

	static inline int xprt_connected(struct rpc_xprt *xprt)
	{
	return test_bit(XPRT_CONNECTED, &xprt->state);
	}

	static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
	{
	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
	}

	static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
	{
	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
	}

	static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
	{
	smp_mb__before_atomic();
	clear_bit(XPRT_CONNECTING, &xprt->state);
	smp_mb__after_atomic();
	}

	static inline int xprt_connecting(struct rpc_xprt *xprt)
	{
	return test_bit(XPRT_CONNECTING, &xprt->state);
	}

	static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
	{
	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
	}

	static inline void xprt_set_bound(struct rpc_xprt *xprt)
	{
	test_and_set_bit(XPRT_BOUND, &xprt->state);
	}

	static inline int xprt_bound(struct rpc_xprt *xprt)
	{
	return test_bit(XPRT_BOUND, &xprt->state);
	}

	static inline void xprt_clear_bound(struct rpc_xprt *xprt)
	{
	clear_bit(XPRT_BOUND, &xprt->state);
	}

	static inline void xprt_clear_binding(struct rpc_xprt *xprt)
	{
	smp_mb__before_atomic();
	clear_bit(XPRT_BINDING, &xprt->state);
	smp_mb__after_atomic();
	}

	static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
	{
	return test_and_set_bit(XPRT_BINDING, &xprt->state);
	}

	#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
	extern unsigned int rpc_inject_disconnect;
	static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
	{
	if (!rpc_inject_disconnect)
	return;
	if (atomic_dec_return(&xprt->inject_disconnect))
	return;
	atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
	xprt->ops->inject_disconnect(xprt);
	}
	#else
	static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
	{
	}
	#endif

	#endif /* __KERNEL__*/

	#endif /* _LINUX_SUNRPC_XPRT_H */