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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Request reply cache. This was heavily inspired by the
4 * implementation in 4.3BSD/4.4BSD.
5 *
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 */
8
9#ifndef NFSCACHE_H
10#define NFSCACHE_H
11
12#include <linux/sunrpc/svc.h>
13
14/*
15 * Representation of a reply cache entry.
16 *
17 * Note that we use a sockaddr_in6 to hold the address instead of the more
18 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage
19 * is much larger than a sockaddr_in6.
20 */
21struct svc_cacherep {
22 struct {
23 /* Keep often-read xid, csum in the same cache line: */
24 __be32 k_xid;
25 __wsum k_csum;
26 u32 k_proc;
27 u32 k_prot;
28 u32 k_vers;
29 unsigned int k_len;
30 struct sockaddr_in6 k_addr;
31 } c_key;
32
33 struct rb_node c_node;
34 struct list_head c_lru;
35 unsigned char c_state, /* unused, inprog, done */
36 c_type, /* status, buffer */
37 c_secure : 1; /* req came from port < 1024 */
38 unsigned long c_timestamp;
39 union {
40 struct kvec u_vec;
41 __be32 u_status;
42 } c_u;
43};
44
45#define c_replvec c_u.u_vec
46#define c_replstat c_u.u_status
47
48/* cache entry states */
49enum {
50 RC_UNUSED,
51 RC_INPROG,
52 RC_DONE
53};
54
55/* return values */
56enum {
57 RC_DROPIT,
58 RC_REPLY,
59 RC_DOIT
60};
61
62/*
63 * Cache types.
64 * We may want to add more types one day, e.g. for diropres and
65 * attrstat replies. Using cache entries with fixed length instead
66 * of buffer pointers may be more efficient.
67 */
68enum {
69 RC_NOCACHE,
70 RC_REPLSTAT,
71 RC_REPLBUFF,
72};
73
74/* Cache entries expire after this time period */
75#define RC_EXPIRE (120 * HZ)
76
77/* Checksum this amount of the request */
78#define RC_CSUMLEN (256U)
79
80int nfsd_reply_cache_init(void);
81void nfsd_reply_cache_shutdown(void);
82int nfsd_cache_lookup(struct svc_rqst *);
83void nfsd_cache_update(struct svc_rqst *, int, __be32 *);
84int nfsd_reply_cache_stats_open(struct inode *, struct file *);
85
86#endif /* NFSCACHE_H */