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#include <linux/version.h>

#include <linux/types.h>

#include <linux/unistd.h>

#include <linux/sunrpc/clnt.h>

#include <linux/sunrpc/xprt.h>

#include <linux/sunrpc/timer.h>

#define RPC_RTO_MAX (60*HZ)

#define RPC_RTO_INIT (HZ/5)

#define RPC_RTO_MIN (HZ/10)

void

rpc_init_rtt(struct rpc_rtt *rt, long timeo)

{

        long t = (timeo - RPC_RTO_INIT) << 3;

        int i;

        rt->timeo = timeo;

        if (t < 0)

                t = 0;

        for (i = 0; i < 5; i++) {

                rt->srtt[i] = t;

                rt->sdrtt[i] = RPC_RTO_INIT;

        }

        memset(rt->ntimeouts, 0, sizeof(rt->ntimeouts));

}

void

rpc_update_rtt(struct rpc_rtt *rt, int timer, long m)

{

        long *srtt, *sdrtt;

        if (timer-- == 0)

                return;

        if (m == 0)

                m = 1;

        srtt = &rt->srtt[timer];

        m -= *srtt >> 3;

        *srtt += m;

        if (m < 0)

                m = -m;

        sdrtt = &rt->sdrtt[timer];

        m -= *sdrtt >> 2;

        *sdrtt += m;

        /* Set lower bound on the variance */

        if (*sdrtt < RPC_RTO_MIN)

                *sdrtt = RPC_RTO_MIN;

}

/*

 * Estimate rto for an nfs rpc sent via. an unreliable datagram.

 * Use the mean and mean deviation of rtt for the appropriate type of rpc

 * for the frequent rpcs and a default for the others.

 * The justification for doing "other" this way is that these rpcs

 * happen so infrequently that timer est. would probably be stale.

 * Also, since many of these rpcs are

 * non-idempotent, a conservative timeout is desired.

 * getattr, lookup,

 * read, write, commit     - A+4D

 * other                   - timeo

 */

long

rpc_calc_rto(struct rpc_rtt *rt, int timer)

{

        long res;

        if (timer-- == 0)

                return rt->timeo;

        res = (rt->srtt[timer] >> 3) + rt->sdrtt[timer];

        if (res > RPC_RTO_MAX)

                res = RPC_RTO_MAX;

        return res;

}