1 /*
2 * rpcsock.h Declarations for the RPC call interface.
3 *
4 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
5 */
6
7
8 #ifndef _LINUX_RPCSOCK_H
9 #define _LINUX_RPCSOCK_H
10
11 /*
12 * The rpcsock code maintains an estimate on the maximum number of out-
13 * standing RPC requests, using the congestion avoidance implemented in
14 * 44BSD. This is basically the Van Jacobson slow start algorithm: If a
15 * retransmit occurs, the congestion window is halved; otherwise, it is
16 * incremented by 1/cwnd when a reply is received and a full number of
17 * requests are outstanding.
18 *
19 * Upper procedures may check whether a request would block waiting for
20 * a free RPC slot by using the RPC_CONGESTED() macro.
21 *
22 * Note: on machines with low memory we should probably use a smaller
23 * MAXREQS value: At 32 outstanding reqs with 8 megs of RAM, fragment
24 * reassembly will frequently run out of memory.
25 */
26 #define RPC_MAXREQS 32
27 #define RPC_CWNDSCALE 256
28 #define RPC_MAXCWND (RPC_MAXREQS * RPC_CWNDSCALE)
29 /* #define RPC_INITCWND (RPC_MAXCWND / 2) */
30 #define RPC_INITCWND RPC_CWNDSCALE
31 #define RPC_CONGESTED(rsock) ((rsock)->cong >= (rsock)->cwnd)
32
33 /* RPC reply header size: xid, direction, status, accept_status (verifier
34 * size computed separately)
35 */
36 #define RPC_HDRSIZE (4 * 4)
37
38 /*
39 * This describes a timeout strategy
40 */
41 struct rpc_timeout {
42 unsigned long to_initval,
43 to_maxval,
44 to_increment;
45 int to_retries;
46 char to_exponential;
47 };
48
49 /*
50 * This describes a complete RPC request
51 */
52 struct rpc_ioreq {
53 struct rpc_wait * rq_slot;
54 struct sockaddr * rq_addr;
55 int rq_alen;
56 struct iovec rq_svec[UIO_FASTIOV];
57 unsigned int rq_snr;
58 unsigned long rq_slen;
59 struct iovec rq_rvec[UIO_FASTIOV];
60 unsigned int rq_rnr;
61 unsigned long rq_rlen;
62 };
63
64 /*
65 * This is the callback handler for async RPC.
66 */
67 struct rpc_wait;
68 typedef void (*rpc_callback_fn_t)(int, struct rpc_wait *, void *);
69
70 /*
71 * Wait information. This struct defines all the state of an RPC
72 * request currently in flight.
73 */
74 struct rpc_wait {
75 struct rpc_sock * w_sock;
76 struct rpc_wait * w_prev;
77 struct rpc_wait * w_next;
78 struct rpc_ioreq * w_req;
79 int w_result;
80 wait_queue_head_t w_wait;
81 rpc_callback_fn_t w_handler;
82 void * w_cdata;
83 char w_queued;
84 char w_gotit;
85 __u32 w_xid;
86 };
87
88 struct rpc_sock {
89 struct file * file;
90 struct socket * sock;
91 struct sock * inet;
92 struct rpc_wait waiting[RPC_MAXREQS];
93 unsigned long cong;
94 unsigned long cwnd;
95 struct rpc_wait * pending;
96 struct rpc_wait * free;
97 wait_queue_head_t backlog;
98 wait_queue_head_t shutwait;
99 int shutdown;
100 };
101
102 #ifdef __KERNEL__
103
104 /* rpc_call: Call synchronously */
105 int rpc_call(struct rpc_sock *, struct rpc_ioreq *,
106 struct rpc_timeout *);
107 /* These implement asynch calls for nfsiod: Process calls rpc_reserve and
108 * rpc_transmits, then passes the request to nfsiod, which collects the
109 * results via rpc_doio
110 */
111 int rpc_reserve(struct rpc_sock *, struct rpc_ioreq *, int);
112 void rpc_release(struct rpc_sock *, struct rpc_ioreq *);
113 int rpc_transmit(struct rpc_sock *, struct rpc_ioreq *);
114 int rpc_doio(struct rpc_sock *, struct rpc_ioreq *,
115 struct rpc_timeout *, int);
116 struct rpc_sock * rpc_makesock(struct file *);
117 int rpc_closesock(struct rpc_sock *);
118
119 #endif /* __KERNEL__*/
120
121 #endif /* _LINUX_RPCSOCK_H */
122
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