1 files changed, 81 insertions, 0 deletions

diff --git a/include/linux/nfsd/cache.h b/include/linux/nfsd/cache.h
new file mode 100644
index 000000000000..c3a3557c2a5b
--- /dev/null
+++ b/include/linux/nfsd/cache.h
@@ -0,0 +1,81 @@
+/*
+ * include/linux/nfsd/cache.h
+ *
+ * Request reply cache. This was heavily inspired by the
+ * implementation in 4.3BSD/4.4BSD.
+ *
+ * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
+ */
+
+#ifndef NFSCACHE_H
+#define NFSCACHE_H
+
+#ifdef __KERNEL__
+#include <linux/in.h>
+#include <linux/uio.h>
+
+/*
+ * Representation of a reply cache entry. The first two members *must*
+ * be hash_next and hash_prev.
+ */
+struct svc_cacherep {
+        struct hlist_node       c_hash;
+        struct list_head        c_lru;
+
+        unsigned char           c_state,        /* unused, inprog, done */
+                                c_type,         /* status, buffer */
+                                c_secure : 1;   /* req came from port < 1024 */
+        struct sockaddr_in      c_addr;
+        u32                     c_xid;
+        u32                     c_prot;
+        u32                     c_proc;
+        u32                     c_vers;
+        unsigned long           c_timestamp;
+        union {
+                struct kvec     u_vec;
+                u32             u_status;
+        }                       c_u;
+};
+
+#define c_replvec               c_u.u_vec
+#define c_replstat              c_u.u_status
+
+/* cache entry states */
+enum {
+        RC_UNUSED,
+        RC_INPROG,
+        RC_DONE
+};
+
+/* return values */
+enum {
+        RC_DROPIT,
+        RC_REPLY,
+        RC_DOIT,
+        RC_INTR
+};
+
+/*
+ * Cache types.
+ * We may want to add more types one day, e.g. for diropres and
+ * attrstat replies. Using cache entries with fixed length instead
+ * of buffer pointers may be more efficient.
+ */
+enum {
+        RC_NOCACHE,
+        RC_REPLSTAT,
+        RC_REPLBUFF,
+};
+
+/*
+ * If requests are retransmitted within this interval, they're dropped.
+ */
+#define RC_DELAY                (HZ/5)
+
+void    nfsd_cache_init(void);
+void    nfsd_cache_shutdown(void);
+int     nfsd_cache_lookup(struct svc_rqst *, int);
+void    nfsd_cache_update(struct svc_rqst *, int, u32 *);
+
+#endif /* __KERNEL__ */
+#endif /* NFSCACHE_H */