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/*
* rpcsock.h Declarations for the RPC call interface.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#ifndef _LINUX_RPCSOCK_H
#define _LINUX_RPCSOCK_H
/*
* The rpcsock code maintains an estimate on the maximum number of out-
* standing RPC requests, using the congestion avoidance implemented in
* 44BSD. This is basically the Van Jacobson slow start algorithm: If a
* retransmit occurs, the congestion window is halved; otherwise, it is
* incremented by 1/cwnd when a reply is received and a full number of
* requests are outstanding.
*
* Upper procedures may check whether a request would block waiting for
* a free RPC slot by using the RPC_CONGESTED() macro.
*
* Note: on machines with low memory we should probably use a smaller
* MAXREQS value: At 32 outstanding reqs with 8 megs of RAM, fragment
* reassembly will frequently run out of memory.
*/
#define RPC_MAXREQS 32
#define RPC_CWNDSCALE 256
#define RPC_MAXCWND (RPC_MAXREQS * RPC_CWNDSCALE)
/* #define RPC_INITCWND (RPC_MAXCWND / 2) */
#define RPC_INITCWND RPC_CWNDSCALE
#define RPC_CONGESTED(rsock) ((rsock)->cong >= (rsock)->cwnd)
/* RPC reply header size: xid, direction, status, accept_status (verifier
* size computed separately)
*/
#define RPC_HDRSIZE (4 * 4)
/*
* This describes a timeout strategy
*/
struct rpc_timeout {
unsigned long to_initval,
to_maxval,
to_increment;
int to_retries;
char to_exponential;
};
/*
* This describes a complete RPC request
*/
struct rpc_ioreq {
struct rpc_wait * rq_slot;
struct sockaddr * rq_addr;
int rq_alen;
struct iovec rq_svec[UIO_FASTIOV];
unsigned int rq_snr;
unsigned long rq_slen;
struct iovec rq_rvec[UIO_FASTIOV];
unsigned int rq_rnr;
unsigned long rq_rlen;
};
/*
* This is the callback handler for async RPC.
*/
struct rpc_wait;
typedef void (*rpc_callback_fn_t)(int, struct rpc_wait *, void *);
/*
* Wait information. This struct defines all the state of an RPC
* request currently in flight.
*/
struct rpc_wait {
struct rpc_sock * w_sock;
struct rpc_wait * w_prev;
struct rpc_wait * w_next;
struct rpc_ioreq * w_req;
int w_result;
wait_queue_head_t w_wait;
rpc_callback_fn_t w_handler;
void * w_cdata;
char w_queued;
char w_gotit;
__u32 w_xid;
};
struct rpc_sock {
struct file * file;
struct socket * sock;
struct sock * inet;
struct rpc_wait waiting[RPC_MAXREQS];
unsigned long cong;
unsigned long cwnd;
struct rpc_wait * pending;
struct rpc_wait * free;
wait_queue_head_t backlog;
wait_queue_head_t shutwait;
int shutdown;
};
#ifdef __KERNEL__
/* rpc_call: Call synchronously */
int rpc_call(struct rpc_sock *, struct rpc_ioreq *,
struct rpc_timeout *);
/* These implement asynch calls for nfsiod: Process calls rpc_reserve and
* rpc_transmits, then passes the request to nfsiod, which collects the
* results via rpc_doio
*/
int rpc_reserve(struct rpc_sock *, struct rpc_ioreq *, int);
void rpc_release(struct rpc_sock *, struct rpc_ioreq *);
int rpc_transmit(struct rpc_sock *, struct rpc_ioreq *);
int rpc_doio(struct rpc_sock *, struct rpc_ioreq *,
struct rpc_timeout *, int);
struct rpc_sock * rpc_makesock(struct file *);
int rpc_closesock(struct rpc_sock *);
#endif /* __KERNEL__*/
#endif /* _LINUX_RPCSOCK_H */
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