1 /*
2  * Request reply cache. This was heavily inspired by the
3  * implementation in 4.3BSD/4.4BSD.
4  *
5  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6  */
7 
8 #ifndef NFSCACHE_H
9 #define NFSCACHE_H
10 
11 #include <linux/sunrpc/svc.h>
12 
13 /*
14  * Representation of a reply cache entry.
15  */
16 struct svc_cacherep {
17 	struct hlist_node	c_hash;
18 	struct list_head	c_lru;
19 
20 	unsigned char		c_state,	/* unused, inprog, done */
21 				c_type,		/* status, buffer */
22 				c_secure : 1;	/* req came from port < 1024 */
23 	struct sockaddr_in	c_addr;
24 	__be32			c_xid;
25 	u32			c_prot;
26 	u32			c_proc;
27 	u32			c_vers;
28 	unsigned long		c_timestamp;
29 	union {
30 		struct kvec	u_vec;
31 		__be32		u_status;
32 	}			c_u;
33 };
34 
35 #define c_replvec		c_u.u_vec
36 #define c_replstat		c_u.u_status
37 
38 /* cache entry states */
39 enum {
40 	RC_UNUSED,
41 	RC_INPROG,
42 	RC_DONE
43 };
44 
45 /* return values */
46 enum {
47 	RC_DROPIT,
48 	RC_REPLY,
49 	RC_DOIT,
50 	RC_INTR
51 };
52 
53 /*
54  * Cache types.
55  * We may want to add more types one day, e.g. for diropres and
56  * attrstat replies. Using cache entries with fixed length instead
57  * of buffer pointers may be more efficient.
58  */
59 enum {
60 	RC_NOCACHE,
61 	RC_REPLSTAT,
62 	RC_REPLBUFF,
63 };
64 
65 /*
66  * If requests are retransmitted within this interval, they're dropped.
67  */
68 #define RC_DELAY		(HZ/5)
69 
70 int	nfsd_reply_cache_init(void);
71 void	nfsd_reply_cache_shutdown(void);
72 int	nfsd_cache_lookup(struct svc_rqst *);
73 void	nfsd_cache_update(struct svc_rqst *, int, __be32 *);
74 
75 #ifdef CONFIG_NFSD_V4
76 void	nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp);
77 #else  /* CONFIG_NFSD_V4 */
nfsd4_set_statp(struct svc_rqst * rqstp,__be32 * statp)78 static inline void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
79 {
80 }
81 #endif /* CONFIG_NFSD_V4 */
82 
83 #endif /* NFSCACHE_H */
84